AS
Atmospheric Sciences

Atmospheric Sciences

Buckle up! Its about to get bumpy on the plane.

Buckle up! Its about to get bumpy on the plane.

Clear-Air Turbulence (CAT) is a major hazard to the aviation industry. If you have ever been on a plane you have probably heard the pilots warn that clear-air turbulence could occur at any time so always wear your seatbelt. Most people will have experienced it for themselves and wanted to grip their seat. However, severe turbulence capable of causing serious passengers injuries is rare. It is defined as the vertical motion of the aircraft being strong enough to force anyone not seat belted to leave the chair or floor if they are standing. In the United States alone, it costs over 200 million US dollars in compensation for injuries, with people being hospitalised with broken bones and head injuries. Besides passengers suffering serious injuries, the cabin crew are most vulnerable as they spend most of the time on their feet serving customers. This results in an additional cost if they are injured and unable to work.

Clear-air turbulence is defined as high altitude inflight bumpiness away from thunderstorm activity. It can appear out of nowhere at any time and is particularly dangerous because pilots can’t see or detect it using on-board instruments.  Usually the first time a pilot is aware of the turbulence is when they are already flying through it. Because it is a major hazard, we need to know how it might change in the future, so that the industry can prepare if necessary. This could be done by trying to improve forecasts so that pilots can avoid regions likely to contain severe turbulence or making sure the aircraft can withstand more frequent and severe turbulence.

Our new paper published in Geophysical Research Letters named ‘Global Response of Clear-Air Turbulence to Climate Change’ aims at understanding how clear-air turbulence will change in the future around the world and throughout the year. What our study found was that, the busiest flight routes around the world would see the largest increase in turbulence. For example, the North Atlantic, North America, North Pacific and Europe (see Figure 1) will see a significant increase in severe turbulence which could cause more problems in the future. These regions see the largest increase because of the Jet Stream. The Jet Stream is a fast flowing river of air that is found in the mid-latitudes. Clear-air turbulence is predominantly caused by the wind traveling at different speeds around the Jet Stream. Climate change is expected to increase the Jet Stream speed and therefore increase the vertical wind shear, causing more turbulence.

To put these findings in context, severe turbulence in the future will be as frequent as moderate turbulence historically. Anyone who is a frequent flyer will have likely experienced moderate turbulence at some point, but fewer people have experienced severe turbulence. Therefore, this study suggests this will change in the future with most frequent flyers experiencing severe turbulence on some flight routes as well as even more moderate turbulence. Our study also found moderate turbulence will become as frequent in the summer as it has done historically in winter. This is significant because although clear-air turbulence is more likely in winter, it will however now become much more of a year round phenomenon (see Figure 2).

Figure 2: Seasonal variation in turbulence intensity.

 

This increase in clear-air turbulence highlights the importance for improving turbulence forecasting. Current research has shown that using ensemble forecasts (many forecasts of the same event) and also using more turbulence diagnostics than the one we used in this study can improve the forecast skill. By improving the forecasts, we could consistently avoid the areas of severe turbulence or make sure passengers and crew are seat-belted before the turbulence event occurs. Unfortunately, as these improvements are not yet fully operational, you can still reduce your own risk of injury by making sure you wear your seat belt as much as possible so that, if the aircraft does hit unexpected turbulence, you would avoid serious injuries.


This blog has been prepared by Luke Storer (@LukeNStorer), Department of Meteorology, University of Reading, Reading, UK and edited by Dasaraden Mauree (@D_Mauree). 

Volcanic Ash Particles Hold Clues to Their History and Effects

Volcanic Ash Particles Hold Clues to Their History and Effects
Volcanic Ash as an Active Agent in the Earth System (VA3): Combining Models and Experiments; Hamburg, Germany, 12–13 September 2016

Volcanic ash is a spectacular companion of volcanic activity that carries valuable information about the subsurface processes. It also poses a range of severe hazards to public health, infrastructure, aviation, and agriculture, and it plays a significant role in biogeochemical cycles.

Scientists can examine ash particles from volcanic eruptions for clues to the history of their journey from the lithosphere (Earth’s crust and upper mantle) to atmosphere, hydrosphere, and biosphere (Figure 1). These tephra particles are less than 2 millimeters in diameter, and they record most of the history on or near their surfaces. Understanding the physicochemical properties of the ash particle surfaces is essential to deciphering the underlying volcanic and atmospheric processes and to predicting the widespread effects and hazards posed by these small particles. This has been extensively investigated recently but several fundamental questions remain open.

Figure 1: Particle surface properties strongly affect the life cycle and effects of volcanic ash particles within the Earth system (Credit: G. Hoshyaripour).

For example, ash surface generation and alteration through processes occurring during eruption (e.g., fragmentation and recycling) and after eruption (e.g., aggregation, cloud chemistry, and microphysics) are not yet quantitatively well understood and thus are not fully implemented in the models. Therefore, gaps remain in our understanding of the volcanic and atmospheric life cycle of the ash and how this life cycle is linked to the ash’s surface properties and environmental effects. This limitation hinders the reliable estimation of far-field airborne ash concentrations, a central factor in assessing the ash hazard for aviation.

Addressing the challenges in volcanic ash surface characterization requires close collaboration of experts in laboratory experiments, in situ measurements, space-based observations, and numerical modeling to co-develop reliable assessment tools for both fundamental research and operational purposes. These actions should involve specialists from geochemistry, geology, volcanology, and atmospheric sciences to combine the advanced experimental and observational data on rate parameters of physicochemical processes and ash surface characteristics with state-of-the-art atmospheric models that incorporate aerosol chemistry, microphysics, and interactions among ash particles, clouds, and solar radiation in local to global scales.

As the first step in this direction, a joint European Geophysical Union (EGU) and American Geophysical Union (AGU) session on volcanic ash is organized in the upcoming general assembly and fall meeting entitled: Volcanic Ash—Generation, Transport, Impacts, and Applications. The next steps should include 1) initiation a collaborative network with two working groups on the physical and geochemical life cycles of volcanic ash; 2) development an integrated modeling, observational, and experimental data compilation on mid- to large-intensity eruptions to assist with benchmark modeling.

These actions should be linked to the existing activities within the International Association of Volcanology and Chemistry of the Earth’s Interior, EGU, and AGU.

The workshop was supported by the excellence cluster CliSAP (DFG EXE 177).

This blog post has been originally prepared as a meeting report referring to a workshop in Hamburg, Germany, sponsored by the excellence cluster CliSAP (DFG EXE 177).


This blog has been prepared by Ali Hoshyaripour (@Hoshyaripour – email: ali.hoshyaripour@kit.edu), Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Germany and edited by Dasaraden Mauree (@D_Mauree). 

How can we use meteorological models to improve building energy simulations?

How can we use meteorological models to improve building energy simulations?

Climate change is calling for various and multiple approaches in the adaptation of cities and mitigation of the coming changes. Because buildings (residential and commercial) are responsible of about 40% of energy consumption, it is necessary to build more energy efficient ones, to decrease their contribution to greenhouse gas emissions.

But what is the relation with the atmosphere. It is two folds: firstly, in a previous post, I have already described what is the impact of the buildings / obstacles on the air flow and on the air temperature. Secondly, the fact that the climate or surrounding environment is influenced, there will be a significant change in the energy consumption of these buildings.  Currently, building energy simulation tool are using data usually gathered outside of the city and hence not representative of the local context. Thus it is crucial to be able to have necessary tools that capture both the dynamics of the atmosphere and also those of a building to design better and more sustainable urban areas.

In the present work, we have brought these two disciplines together by developing a multi-scale model. On the one side, a meteorological model, the Canopy Interface Model (CIM), was developed to obtain high resolution vertical profile of wind speed, direction and air temperature. On the other hand, an energy modelling tool, CitySim, is used to evaluate the energy use of the buildings as well as the irradiation reaching the buildings.

With this coupling methodology setup we have applied it on the EPFL campus, in Switzerland.  We have compared the modelling results with data collected on the EPFL campus for the year 2015. The results show that the coupling lead to a computation of the meteorological variables that are in very good agreement. However, we noted that for the wind speed at 2m, there is still some underestimation of the wind speed. One of the reason for this is that the wind speed close to the ground is very low and there is a higher variability at this height.

Comparison of the wind speed (left) and air temperature (right) at 2m (top) and 12m (bottom).

We intend to improve this by developing new parameterization in the future for the wind speed in an urban context by using data currently being acquired in the framework of the MoTUS project. One surprising result from this part of the study, is the appearance inside of an urban setup of a phenomena call Cold Air Pools which is very typical of valleys. The reason for this is the lack of irradiation reaching the surface inside of dense urban parts.

Furthermore, we have seen some interesting behaviour in the campus for some particular buildings such as the Rolex Learning Center. Buildings with different forms and configuration, reacted very differently with the local and standard dataset. We designed a series of additional simulation using multiple building configuration and conducted a sensitivity analysis in order to define which parameters between the wind speed and the air temperature had a more significant impact on the heating demand (see Figure 1). We showed that the impact of a reduction of 1°C was more important than a reduction of 1m s-1.

Figure 1. Heating demand of the five selected urban configurations (black dots), as function of the variation by +1°C (red dots) and -1°C (blue dots) of the air temperature, and by +1.5 m s-1 (violet dots) and -1.5 m s-1 (orange dots).

Finally, we also analysed the energy consumption of the whole EPFL campus. When using standard data, the difference between the simulated and measured demand was around 15%. If localized weather data was used, the difference was decreased to 8%. We have thus been able to reduce the uncertainty of the data by 2. The use of local data can hence improve the estimation of building energy use and will hence be quite important when building become more and more efficient.

Reference / datasets

The paper (Mauree et al., Multi-scale modelling to evaluate building energy consumption at the neighbourhood scale, PLOS One, 2017) can be accessed here and data needed to reproduce the experiment are also available on Zenodo.

June 2017 Newsletter

June 2017 Newsletter

The blog will now also host a newsletter specially dedicated to Early Career Scientists of the Atmospheric Sciences Divisions.


ECS – AS News – Issue 1 – June 2017


FROM THE PRESIDENT

Dear Early Career Atmospheric Scientists,

I hope that you by now have digested all the excellent science and events that took place during the EGU GA in April. I would like to thank you all for your contribution that made the Atmospheric Sciences program such a great success! Overall, ECS represent about 50% of the people attending the EGU GA and almost 20% of the participants are associated with the Atmospheric Sciences Division, so you are really a vital part of the community. I hope that we can make next year’s program even better for you, so please feel free to suggest ways on how we can improve things. An additional option is of course to join forces with Ali Hoshyaripour and the rest of the AS ECS team of representatives – they are doing a great job thinking about how to support, inform and connect all Early Career Atmospheric Scientists!

I wish you all a wonderful summer.

Annica Ekman – President of the EGU Atmospheric Division


NEWS

Outstanding student poster and PICO (OSSP) Awards

We are pleased to announce the winners of OSSP award 2017 in AS division. Congratulations to all winners!

  1. EGU2017-7557 by Laura Suarez-Gutierrez et al. “Internal Variability in Simulated and Observed Tropical Tropospheric Temperature Trends.”(AS1.25/CL4.14 – Past and future atmospheric temperature changes and their drivers (co-organized))
  2. EGU2017-12492 by Camilla Francesca Brunello et al.  “Decadal record of monsoon dynamics across the Himalayas using tree ring data” (AS1.18/CL3.09 – The global monsoons in current, future and palaeoclimates and their role in extreme weather and climate events (co-organized))
  3. EGU2017-2727 by Denise Assmann et al. “Spatio-temporal aerosol particle distributions in the UT/LMS measured by the IAGOS-CARIBIC Observatory.” (AS3.14 – Atmospheric composi2tion variability and trends, PICO session Wed, 14:04-15:00, PICO5a.4)
  4. EGU2017-6542 by Thibaut Dauhut et al. “An isentropic perspective of the atmospheric overturning induced by Hector the Convector.” (AS1.31 – Atmospheric Convection)
  5. EGU2017-8223 by Stefanie Unterguggenberger et al.  “Investigating metals in the MLT using astronomical facilities” (AS4.2 – Impacts of cosmic dust in the terrestrial and other planetary atmospheres)
  6. EGU2017-317 by Yugen Li et al. “Quantifying the relationship between visibility degradation and PM2.5 constituents at a suburban site in Hong Kong: Differentiating contributions from hydrophilic and hydrophobic organic compounds.” (AS3.8 – Radiative effects and global aerosol forcing estimates of  natural and anthropogenic aerosols.)

Division’s Social Media

The division has now an official page on Instagram (@eguasd). Nando Iglesias Suarez (right) is the admin of this page and division’s Facebook. Michelle Cain (left) is the admin of division’s Tweeter account (@EGU_atmos).

Mchelle Cain (left) and Nando Iglesias Suarez (right)

If you wish to share an interesting post with your AS fellows, please send it as a message to the accounts mentioned above. Michelle and Nando will take care of the rest 🙂


VIRTUAL INTERVIEW

Do you want to know more about the career building in the EU and USA? Are you wondering about differences and similarities between two research systems? … We have invited Prof. Guy Brasseur, a renowned atmospheric scientist who has immense experience in both EU and USA, to answer your questions about:

Atmospheric Sciences Career in EU and USA: Similarities and Differences

Between 16-20 June 2017, you can send your questions on Facebook, Tweeter, Instagram with the hashtag #AS_Career or by email to ecs-as@egu.eu. Follow us on FB and Twitter for updates.

Biosketch of Prof. Guy Brasseur

Guy P. Brasseur

Guy P. Brasseur studied at the Free University of Brussels, Belgium and obtained his PhD in 1978. During the following years, he worked at the Belgian Institute for Space Aeronomy, where he developed advanced models of photochemistry and transport in the middle atmosphere. In 1988, he moved to NCAR where he became Director of Atmospheric Chemistry Division in 1990.

Between 1992 and 1996, he served as Editor in Chief of the Journal of Geophysical Research (Atmospheres), and during the period 1994-2001, became Chair of the International Atmospheric Chemistry Project (IGAC) of the International Geosphere-Biosphere Program (IGBP). On January 2000, Brasseur moved to Hamburg, Germany, where he became Director at the Max Planck Institute for Meteorology, and Honorary Professor at the Universities of Hamburg and Brussels. From 2002 to 2005, he was the Chair of the Scientific Committee of the International Geosphere Biosphere Programme (IGBP). He was a Coordinating Lead Author for the fourth Assessment Report (WG-1) of the International Panel for Climate Change(IPCC). The IPCC was awarded the Peace Nobel Prize in 2007. Between January 2006 and July 2009, Brasseur was an Associate Director of the National Center for Atmospheric Research (NCAR) and Head of the Earth and Sun Systems Laboratory. Between July 2009 and June 2014, he directed the Climate Service Center (CSC) in Hamburg, Germany. He is now an External Member of the Max Planck Institute for Meteorology and a Distinguished Scholar at NCAR.

Brasseur is a member of the Academy of Sciences of Hamburg, an associate member of the Royal Academy of Belgium (Class: Technology and Society) and a foreign member of the Norwegian Academy of Sciences. He is also a member of the Academia Europea. He is Doctor Honoris Causa of the Universities of Oslo, Paris (Pierre and Marie Curie) and Athens. He was awarded several prizes including the 2014 Abate Molina Prize in Chile. Brasseur is currently the Chair of the Joint Science Committee of the World Climate Research Programme (WCRP). His primary scientific interests are questions related to Global Change, climate variability, chemistry-climate relations, biosphere-atmosphere interactions, climate change, stratospheric ozone depletion, global air pollution including tropospheric ozone, solar-terrestrial relations. He has contributed in more than 200 peer-reviewed publications and books and has been very active in climate science communication and knowledge dissemination.


FUTURE EVENTS

Summer school on Atmospheric Chemistry and Dynamics

The summer school on “Atmospheric Chemistry and Dynamics” will be held at Forschungszentrum Jülich between 25 and 29 September 2017.

Registration deadline: 15 July 2017. Read more

EGU Financial Support for Training Schools

The EGU welcomes proposals for financial support of Training Schools to be held in the year 2018. Successful proposals result in high-profile EGU events.

Application deadline: 15 August 2017 Read more


OPEN POSITIONS

The Institute of Oceanography at the Polish Acadmy of Sciences offers a PhD and a Postdoc position.
Application deadline for the PhD position is 30 August 2017. PhD position (174.2 KB)

Application deadline for the Postdoc position is 31 September 2017. Postdoc position (172.2 KB)

The Vienna Doctoral School of Physics offers new PhD fellowships.

Application deadline: 7 July 2017. Read more


This blog has been prepared by Ali Hoshyaripour (@Hoshyaripour) and edited by Dasaraden Mauree (@D_Mauree). Send your comments, suggestions and contributions to ECS-AS newsletter at ecs-as@egu.eu.

The art of turning climate change science to a crochet blanket

The art of turning climate change science to a crochet blanket

We welcome a new guest post from Prof. Ellie Highwood on why she made a global warming blanket and how you could the same!

What do you get when you cross crochet and climate science?
A lot of attention on Twitter.
At the weekend I like to crochet. Last weekend I finished my latest project and posted the picture on Twitter. And then had to turn the notifications off because it all went a bit noisy. The picture of my “global warming blanket” rapidly became my top tweet ever, with more retweets and likes than anything else. Apparently I had found a creative way to visualise trends in global mean temperature. I particularly liked the “this is the most frightening knitwear I have seen all year” comment. Given the interest on Twitter I thought I had better answer a few of the questions in a blog post. Also, it would be great if global warming blankets appeared all over the world.

How did you get the idea?
The global warming blanket was based on “temperature” blankets made by crocheters around the world. Their blankets consist of one row, or square, of crochet each day, coloured according to the temperature at their location. They look amazing and show both the annual cycle and day-to-day variability. Other people make “sky” blankets where the colours are based on the sky colour of the day – this results in a more muted grey-blue-white colour palette.
I wondered what the global temperature series would look like as a blanket. Also, global warming is often explained as greenhouse gases acting like a blanket, trapping infrared radiation and keeping the Earth warm. So that seemed like an interesting link. I also had done several rainbow themed blankets in the past and had a lot of yarn left that needed using.

Where did the data come from?

I used the annual and global mean temperature anomaly compared to 1900-2000 mean as a reference period as available from NOAA. This is what the data looks like shown more conventionally.

Global temperature anomalies (source: NOAA)

I then devised a colour scale using 15 different colours each representing a 0.1 °C data interval. So everything between 0 and 0.099 was in one colour for example. Making a code for these colours, the time series can be rewritten as in the table below. It is up to the creator to then choose the colours to match this scale, and indeed which years to include. I was making a baby sized blanket so chose the last 100 years, 1916-2016.

Because of these choices, and the long reference period, much of the blanket has relatively muted colour differences that tend to emphasise the last 20 years or so. There are other data sets available, and other reference periods and it would be interesting to see what they looked like. Also the colours I used were determined mainly by what I had available; if I were to do another one, I might change a few around (dark pink looks too much like red in the photograph and needed a darker blue instead of purple for the coldest colour), or even use a completely different colour palette – especially as rainbow colour scales aren’t great as they can distort data and render it meaningless if you are colour blind. Ed Hawkins kindly provided me with a more user friendly colour scale which I love and may well turn into a scarf for myself (much quicker than a blanket!).

#endrainbow colour scale (from E. Hawkins)

How can I recreate this?
If you want to create something similar, you will need 15 different colours if you want to do the whole 1850-2016 period. You will need relatively more yarn in colours 3-7 than other colours (if, like me you are using your stash). You can use any stitch or pattern but since you want the colour changes to be the focus of the blanket, I would choose something relatively simple. I used rows of treble crochet (UK terms) and my 100 years ended up being about 90 cm by 110 cm. You can of course choose any width you like for your blanket, or make a scarf by doing a much shorter foundation row. It goes without saying that it could also be knitted. Or painted. Or woven. Or, whatever your particular craft is.

If you look closely (check out arrows on the figure at the top) you can see the 1997-1998 El Nino (relatively warm yellow stripe amongst the pink – in this photo the dark pink looks red – I might change this colour if I did it again), 1991/92 Pinatubo eruption (relatively cool pink year) as well as cool periods 1929, and 1954-56 and the relatively warm 1940-46. Remember that these are global temperature anomalies and may not match your own personal experience at a given location!

Table with the colour codes used to make the global warming blanket

How long did it take?
I used a very simple stitch, so for a blanket this size, it was a couple of months (note I only crochet in the evenings 2 or 3 evenings a week for a couple of hours with more at some weekends). It helped that the Champions League was on during this time as other members of the household were happy to sit around watching football whilst I crocheted. Weave the ends in as you go. There are a lot of them, and I had to do them all at the end. The time flies because….

Why do I crochet?
I like crochet because you can do simple projects whilst thinking about other things, watching TV or listening to podcasts, or, you can do more complicated things which require your full attention and divert your brain from all other things. There is also something meditative about crochet, as has been discussed here. I find it a good way to destress. Additionally, a lot of what I make is for gifts or for charities and that is a really good feeling.

What’s next?
Suggestions have come in for other time series blankets e.g. greys for aerosol optical depth punctuated by red for volcanic eruptions, oranges and yellows punctuated by black for solar cycle (black being high sun spot years), a central England temperature record. Blankets take time, but scarves could be quicker so I might test a few of these ideas out over the next few months. Would love to hear and see more ideas, or perhaps we could organise a mass “global warming blanket” make-athon around the world and then donate them to communities in need.

And finally.
More seriously, whilst lots of the initial comments on Twitter were from climate scientists, there are also a lot from a far more diverse set of folks. I think this is a good example of how if we want to reach out, we need to explore different ways of doing so. There are only so many people who respond to graphs and charts. And if we can find something we are passionate about as a way of doing it, then all the better.

This is post has also been published here.

Edited by Dasaraden Mauree


Ellie Highwood is Professor of Climate Physics in the Department of Meteorology at the University of Reading. She did a Bsc in Physics at the University of Manchester before studying for a PhD at Reading, where she has been ever since! Her research interests concern the role of atmospheric particulates (aerosol) in climate and climate change. She has led two international aircraft campaigns to measure the properties of aerosol and has been involved in many others. Research projects have considered Saharan dust, volcanoes, and aerosols from human activities. She has over 40 publications in the peer reviewed literature and a few media appearances. She also teaches introductory meteorology and climate change to undergraduates, and project management to PhD students. Previously she has been a member of RMetS Council and Education Committee, and Editor of Society News. She also writes a regular “climate scientist” column for the Weather magazine. She tweets as @EllieHighwood.

Do you want to establish a career in the atmospheric sciences? Interview with the Presidents of the AMS and the EGU-AS Division.

http://www.esa.int/spaceinimages/Images/2015/01/Ecosystem_Earth

Establishing a career in the atmospheric sciences can be challenging. There are many paths to take and open questions. Fortunately, those paths and questions have been thoroughly explored by members of our community and their experiences can provide guidance. In light of this, in September 2016 Ali Hoshyaripour [Early Career Scientists (ECS) representative of the European Geoscience Union’s Atmospheric Sciences division (EGU-AS)] and Monique Kuglitsch [Senior International Outreach/Communications Specialist at the American Meteorological Society (AMS)] collaborated on a virtual interview of the presidents of our organizations: Annica Ekmann (AE) and Fred Carr (FC), respectively, with questions provided by early career scientists. You can find below a summary of the different questions and answers.

On education

Red Latinoamericana de estudiantes en Ciencias Atmosféricas y Meteorología (RedLAtM) opened the interview series by asking AE and FC, “did something important mark your life?”

AE: I can’t think of any specific event that changed my life, but spending some time abroad as a Post-Doc and visiting scientist has been very important to me. Both from a professional point of view, to learn from a new environment, but also on a personal level.

FC: I didn’t have a major life-changing moment but several very important ones. In 1969, after I received my B.S. degree, 100% of college graduates were drafted into the military (this was at the height of the Vietnam War). However, because I had a slight hearing deficit, I was ineligible for military service, and I was able to begin graduate school. Had I served in the military, my career path would have been much different. Later, after receiving my PhD and while working as a post-doc for Dr. Lance Bosart at SUNY-Albany, I began applying for faculty positions. I eventually had to decide between an offer from the University of Oklahoma (OU) and waiting for another university to decide among several candidates. I chose the “bird-in-the-hand” option, and joined the School of Meteorology at OU, which at that time had only 6 full-time faculty and was housed in the oldest building on campus. Now we have over 20 faculty and are housed in the magnificent National Weather Center, so that was a fortunate decision. And, of course, getting married to my wonderful wife Meg in 1972, and the birth of my son Brett in 1985 were very positive milestones in my life.

RedLAtM followed-up by asking AE and FC, “why did you both decide to pursue a career in atmospheric sciences?”

AE: My path into science in general, and atmospheric science in particular, was not straight-forward. I’ve always liked math and started my undergraduate education in math and physics. I soon found myself a bit “lost in theory” and wanted concrete problems where I could apply the knowledge. That was how I was drawn towards a Master’s program in meteorology. I was sure my future career would be as a weather forecaster until I started working on my degree project. I really enjoyed this first experience working as a scientist; learning about the problem, developing a tool to study the problem (in my case a numerical model), analyzing the results and then summarizing and presenting the results. So after my degree project I applied for a PhD student position. Then one thing just followed after another… I really enjoy working as scientist, I like the challenges it brings and also that I constantly learn new things from students and colleagues.

FC: I developed a strong interest in atmospheric science because of my love of skiing (which I started at age 5) and subsequent love of snowstorms. I grew up on the Massachusetts coast just northeast of Boston (Beverly) which meant that we were near the rain–snow line of almost every winter storm that passed over the northeast U.S. Thus I followed the weather forecasts and snow observations extremely closely, and decided I wanted to be a meteorologist. My interest in atmospheric science has increased ever since and today, at age 69, I am still skiing and still vicariously following closely all U.S. snowstorms and snow amount reports!

RedLAtM also wanted to know from AE and FC, “how should a young person guide his/her path as student and scientist in order to reach those institutions like the ones you lead?”

AE: A solid PhD education followed by a Postdoctoral position in a good lab is of course important. But I also think it’s essential to be in an environment where you personally and professionally feel appreciated and get good support, otherwise it’s easy to lose the enthusiasm when things turn difficult—which they will at some point. After a Post-Doc, other characteristics than your scientific skills will also become more and more important; project management skills, time management skills, leadership skills, administration skills, etc. If there are opportunities to learn these skills on the way, even at a small scale, it’s a good idea to take them.

FC: My advice will be targeted toward becoming involved in the American Meteorological Society (AMS). One can begin as an undergraduate student by attending scientific meetings, especially the AMS Annual Meeting that has so many activities (Career Fair, Student Conference, Exhibit Hall, etc.) from which they can benefit. As a graduate student, one can begin giving oral and poster presentations at the many conferences/symposia the AMS sponsors every year. The AMS also has meetings that are attractive to the private sector as well (Broadcast; Weather and Forecasting; Washington Forum, etc.), so you can remain involved in the AMS no matter what your career path is. The AMS has over 100 Boards and Committees addressing a wide spectrum of issues, many of which are listed here: https://www.ametsoc.org/ams/index.cfm/about-ams/ams-commissions-boards-and-committees/complete-list-of-commissions-boards-and-committees/ and nearly all of them desire to have 1–2 student members. For early career scientists seeking more involvement in the AMS, I recommend joining one of the 30 Scientific and Technological Activities Commission (STAC) committees in the discipline that matches your interest. Also note the “Student Opportunities” link on the STAC website (https://www.ametsoc.org/stac/). The Commissions on Professional Affairs and on the Weather, Water and Climate Enterprise have many volunteer opportunities for those in the private and public sectors (see first URL above). As your career proceeds, you can become more involved in the leadership of the various commissions, boards and committees, and eventually to major leadership positions in the Society.

RedLAtM posed their next question to FC, “which universities are the best for doing postgraduate studies in Tropical/Subtropical Dynamic applied in numerical weather prediction for tropical cyclone forecasting? I’m from Mexico and we have systems coming from two basins: the Atlantic and the Northeast Pacific.”

FC: By “postgraduate studies”, I will assume that you mean research opportunities as a recent PhD recipient. First, your PhD advisor may know of post-doctoral opportunities in his/her own research group or in tropical research groups at other institutions such as the Universities of Miami or Hawaii. In the U.S., it is possible for almost every doctoral program in atmospheric sciences to have 1–2 experts in tropical meteorology, so one could look over these program for research topics in your areas of interest (the following web site provides a list of these doctoral institutions: http://ametsoc.org/amsucar_curricula/index.cfm). The National Research Council has postdoctoral research opportunities at several organizations such as NOAA, Naval Research Lab, etc. that perform tropical research; the list of these organizations is at http://nrc58.nas.edu/RAPLab10/Opportunity/Programs.aspx. Finally, I will mention NCAR’s Advanced Study Program Postdoctoral Program (at http://www.asp.ucar.edu/pdfp/pd_announcement.php) in which accepted candidates can work with any NCAR scientist they wish, a few of which do study tropical cyclones.

On career

Under the topic of career, Anonymous asked AE and FC “have you experienced ‘impostor syndrome’ and do you have advice for early career researchers who have it?”

AE: I have often felt that I’m not “good enough” and that everybody else is so much smarter and better than I. Personally, what I tended to do was to put all the good characteristics of a number of other people into one ideal person, and then I compared myself with that ideal person, which of course never was a very favorable comparison…. So I’ve stopped doing that J. From a general perspective, I think a good mentor can be very helpful.

FC: I believe I may have experienced a mild form of this syndrome when I first became a professor and I didn’t see myself at the same level as the distinguished professors at Florida State University where I was a student. However, I was getting papers published and receiving research grants, so I must have been doing something right. Eventually I learned that all scientists, being human, have their strengths and weaknesses, and that one can become a colleague of your distinguished peers by recognizing your own strengths and making contributions in these areas. My advice for those who may have impostor syndrome is to talk with people who you admire (one should always try to find mentors wherever you work), as they may have also experienced similar feelings. Also, develop a strong support system among your friends and colleagues, and look at your resume every once in a while to see all the wonderful things you have accomplished!

RedLAtM wanted to know from AE, “do you consider you had to sacrifice more than your male colleagues in order to achieve what have you done as a scientist in atmospheric sciences?”

AE: I don’t feel that I have made specific sacrifices to be a scientist. It’s been challenging sometimes, like many others I do have problems balancing work and private life. But I don’t think it’s a problem that’s unique for academia. It’s unfortunate that the role model of a successful scientist tends to be a person that works day and night, I wish we could change this image. Personally, I would like to see more research groups that do not rely upon, or are focused around, one single person.

RedLAtM wanted to know about FC’s experiences at the National Centers for Environmental (NCEP) and his experiences with models, asking “what has been your experience in the [NCEP]? I mean, what are the challenges that models have nowadays?” and “what are the biggest challenges in modeling?”

FC: Early in my career, I realized that my modeling research efforts would be more worthwhile if the models I worked on were the U.S. operational models used by NCEP. I became one of the few university scientists who spent a sabbatical at NCEP (as well as many visits later on) and was fortunate to be able to make some major improvements to the precipitation forecasts in the NAM and GFS models. It was a wonderful experience working with the NCEP scientists and I encourage all NWP experts to spend time there at some point in their careers. The NWP models today still have room for improvement, which is a good thing since it means that forecasts are still going to get better in the future as we address the current challenges. Some of the major challenges include improving data assimilation (i.e., the way we use data from new observing systems such as dual-pol radar, current and new satellite sensors, pressure data from cell phones, etc.), improving the physics in the models, and how best to design an ensemble of convection-resolving models.

Some of the biggest challenges [in modeling] include: (1) Predictability—at both climate and convective time and space scales. That is, we need to know what the theoretical predictability of the climate system is to know how much room for improvement there is in our climate projections. We need to understand convective predictability to know how long a high-resolution forecast (e.g., 1 km) will successfully evolve convective phenomena. (2) Observations: We now have even operational models forecasting at resolutions much finer than the observational network that provides their initial conditions. We need measurements that, in general, provide higher time and space resolution than we have now, and also those that eliminate the gaps we have such as lower-tropospheric thermodynamic profiling. (3) Data Assimilation: This was mentioned above, and despite the sophistication of today’s assimilation methods, there are still many issues that need research, such as assimilation for convection-resolving models. (4) Physics: We still need to improve our representation of microphysical processes (which are rarely verified), boundary layer turbulence, and surface processes under different wind, stability and vegetation regimes, to name a few. (5) Coupled modeling: Climate models and also medium-range forecasting models need to be coupled with, e.g., ocean models, sea ice models, and land-surface and hydrologic models. So, lots of research opportunities for everyone!

Nadine Borduas asked AE and FC, “is it better to focus on one aspect of [atmospheric sciences] or do a little of all three?”

AE: Difficult question, but I think we need both types in science. We need people that dig into the nitty-gritty details but also the ones that perhaps have a bit more superficial knowledge but are able to connect different subfields. In the beginning of a career, I would say that a relatively narrow focus is better so that you really become a specialist in a topic, method etc. But thereafter, I think it’s good to branch out more and more. Many of the interesting new discoveries today occur in the intersections between different disciplines or sub-disciplines.

FC: If “all three” means physical, dynamic and synoptic (observational) meteorology, then I would recommend that all atmospheric scientists have some knowledge of all three. Dynamicists and modelers still need to know what the observed structure of the atmosphere is, while observationalists (and modelers) need to know how to physically interpret observed (or modelled) behavior of the atmosphere. However, in order to do original research, one must focus on just 1–2 sub-specialty topics within these broad areas in order to achieve the depth one needs to advance the science.

Nadine Borduas also sought advice on developing a research group from AE and FC, asking “when establishing a research group in [atmospheric sciences] how much field/lab/model work to you incorporate in your proposals?”

AE: I assume you mean how much of each one of these components I would incorporate in a proposal? I’m a modeler myself, but collaborate strongly with people doing lab or field work. In most proposals, I therefore either have an experimentalist as a co-applicant and/or refer to specific people that can provide the necessary complementary data and expertise.

FC: If one were to form a new atmospheric research group, it probably would have to concentrate primary on one of two areas: climate and/or mesoscale modeling, or research using new observational tools. It would be difficult to have major expertise in both areas unless you had a very large group (such as at a national laboratory). A few research groups might be formed to do theoretical studies or pure experimental labs (e.g., wind tunnels, fluids laboratory) but these are not as well-funded these days. For a modeling research group, no field or lab work would be needed in the proposals. If you are designing/testing new radars, UAS or thermodynamic profiling systems, considerable field work is required, as well as some laboratory work to refine the instruments. If you were concentrating on measurements from space, then you have no local field or lab work to do (except perhaps some ground-truth validation studies), and your efforts would be concentrated on data processing, data analysis, and product development. Thus the answer depends on the primary purpose of the research group.

RedLAtM wanted to know from FC, “what inspired the foundation of the COMET program?”

FC: The National Weather Service, as it was implementing the “modernization” effort in radars, satellites and workstations in the 1990’s, realized that most forecasters at the time were not well-trained in interpretation of the observations from these systems, nor in convective and mesoscale observations and dynamics, nor in new data analysis software. They wanted a training program much more rigorous than typically given by NWS training courses and thus asked UCAR for assistance. Since each of the NWS Forecast Offices (FO) had a new position known as a Science Operations Officer (SOO), the idea was to train the SOOs at COMET with graduate-level course material, and the SOOs would then be the training focal point at each of the 120 NWS FOs. The instructors for each SOO course would be both university professors and veteran NWS forecasters. I was one of the first COMET instructors of the SOO course, and it was one of the most intense and rewarding teaching experiences I have ever had.

On the role as president of EGU-AS (AE) or AMS (FC)

In regards to her role as President of EGU AS, RedLAtM asked AE, “from your point of view, what is the biggest challenge for women in Atmospheric Sciences? What we have to face in order to leader organizations like EGU AS? Do we have the same opportunities as men have?”

AE: I think that on paper, women and men have the same opportunities to do a career in atmospheric sciences. Still, it’s a fact that more women than men leave science after their PhD or Post-Doc, and you don’t see them as often in leadership positions as men. This problem needs to be fixed, but there is no single and easy solution. I think supporting networks and role models are important, we need to see as big diversity in this respect among women as among men.

RedLAtM also asked AE “what are the youth programs you have supported since you’ve been elected president of EGU AS?”

AE: During the last year we were looking for a new ECS representative for the AS Division and eventually Ali Hoshyaripour was elected for the position. But we had such a large number of really good candidates, so together with Ali, we decided to form an AS Division ECS group that together could come up with activities and help spread information relevant for the AS ECS community. I’m really happy about this initiative, and think it will be a great resource for the AS Division as a whole. In addition, I have of course participated in activities organized by the EGU for early career scientists to meet Division Presidents and other more senior people.

From FC, RedLAtM wanted to know “how we can set up an AMS student chapter in Latin-America?”

FC: I will keep this answer short. The following website explains exactly what is needed to start a Local or Student Chapter of the AMS: https://www.ametsoc.org/ams/index.cfm/about-ams/ams-local-chapters/how-to-start-or-reactivate-a-local-chapter/. I hope you will do so!

Oghenechovwen Christopher Oghenekevwe asked FC about Memoranda of Understanding. Specifically, “does an MoU exist between AMS and any Pan-African institution that allows undergraduate students Meteorology and Climate Science further their career with access to mentorship?”

FC: I don’t believe any MOU currently exists between the AMS and any African countries or organizations. The AMS does have agreements with the meteorological societies in Canada, Australia, India and China, and we will be glad to consider others. Since you mentioned students, you might investigate possible collaborations with the AMS Education Program (https://www.ametsoc.org/ams/index.cfm/education-careers/) and see if some of the teacher training programs could be adapted to student mentoring programs. The head of the Education Program is Wendy Abshire (abshire@ucar.edu) and I recommend that you contact her.

Finally, Chrysanctus Onyeanusi asked FC, “does this society have any scholarship scheme for young meteorology students like me?”

FC: The AMS has Freshman and Minority Scholarships for college freshman and sophomores, and Named Scholarships for seniors. Information about them is at https://www.ametsoc.org/ams/index.cfm/information-for/students/ams-scholarships-and-fellowships/. However, I note that one must be a U.S. citizen or have permanent resident status to be eligible, so if you are an international student, we do not yet have a program for such students. However, it seems to me that we should have one, so I will pass this suggestion to our Centennial Committee, which is thinking about new activities the AMS can engage in as we celebrate our 100th Anniversary in 2019.


AnnikaAnnica Ekman is the President of the Atmospheric Sciences Division (AS) of the European Geosciences Union (EGU) and a Professor of Atmospheric Sciences at Stockholm University, Sweden.

She obtained her PhD in Atmospheric Sciences from Stockholm University in 2001, and was a PostDoc at Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts. Afterward, she returned to Stockholm University as a research scientist, becoming an Associate Professor in Atmospheric Sciences in 2009 and a Full Professor in 2015. Ekman’s research interests include cloud–aerosol interactions and the various ways that aerosol particles influence weather, atmospheric circulation, and the climate system. She is also the editor of Tellus B and co-leads the research areas of aerosols, clouds, turbulence and climate in Bolin Centre for Climate Research, Stockholm.

Since her appointment as the President of EGU AS in 2015, she has strongly supported new ideas to stimulate inter- and cross-disciplinary collaborations.

 


FredAmerican Meteorological Society (AMS) President and Professor of Meteorology, Fred Carr, hails from Beverly, Massachusetts. Carr studied meteorology at Florida State University in Tallahassee, Florida, and was a PostDoc at SUNY-Albany in Albany, New York.

Since 1979, he has been a faculty member at the University of Oklahoma in Norman, Oklahoma. From 1996 to 2010, he was the Director of the School of Meteorology, playing a key role in the expansion of the School and the creation of international exchange programs. Alongside his activities at the University of Oklahoma, he helped found the COMET Program at the University Corporation for Atmospheric Research (UCAR) and has been involved in many professional committees. He recently completed two terms on the UCAR Board of Trustees and is co-Chair of the UCAR Community Modeling Advisory Committee for the National Centers for Environmental Prediction (NCEP). Carr’s research topics include synoptic-, tropical, and mesoscale meteorology; numerical weather prediction; data assimilation; and observational systems.

Throughout his career, Carr has contributed to the AMS in multiple ways, including: a longtime AMS member; Fellow of the AMS; member of AMS Council; Chair of the AMS Board on Higher Education; and editor of Monthly Weather Review, associate editor of Weather and Forecasting, and member of the Editorial Board for the Bulletin of the American Meteorological Society (BAMS).

What? Ice lollies falling from the sky?

What? Ice lollies falling from the sky?

You have more than probably eaten many lollipops as a kid (and you might still enjoy them. The good thing is that you do not necessarily need to go to the candy shop to get them but you can simply wait for them to fall from the sky and eat them for free. Disclaimer: this kind of lollies might be slightly different from what you expect…


Are lollies really falling from the sky?

Eight years ago (in January 2009), a low-pressure weather system coming from the North Atlantic Ocean reached the UK and brought several rain events to the country. Nothing is really special about this phenomenon in Western Europe in the winter. However, a research flight started sampling the clouds in the warm front (transition zone where warm air replaces cold air) ahead of the low-pressure system and discovered hydrometeors (precipitation products, such as rain and snow) of an unusual kind. Researchers named them ‘ice lollies’ due to their characteristic shape and maybe due to their gluttony. The microphysical probes onboard the aircraft, combined with a radar system located in Southern England, allowed them to measure a wide range of hydrometeors, including these ice lollies that were observed for the first time with such concentration levels.

How do ice lollies form?

A recent study (Keppas et al, 2017) explains that ice lollies form when water droplets (size of 0.1 to 0.7 mm) collide with ice crystals with the form of a column (size of 0.25 to 1.4 mm) and freeze on top of them (see Fig. 2).

Fig 2: Formation of an ice lolly: water droplet (the circle) collides with an ice crystal (the column) [Credit: Fig. 1a from Keppas et al., (2017)].

Such ice lollies form in ‘mixed-phase clouds’, i.e. clouds made of water droplets and ice crystals and whose temperature is below the freezing point (0°C). At these temperatures, water droplets can be supercooled, meaning that they stay liquid below the freezing point.

Figure 3 below shows the processes and particles involved in the formation of ice lollies. Ice lollies are mainly found at temperatures between 0 and -6°C, in the vicinity of the warm conveyor belt, which represents the main source of warm moist air that feeds the low-pressure system. This warm conveyor belt brings water vapour that participates in the formation and growth of supercooled water droplets. Ice crystals formed near the cloud tops fall through the warm conveyor belt and collide with the water droplets to form ice lollies.

Fig 3: Processes involved with the formation of ice lollies, which mainly form under the warm conveyor belt [Credit: Fig 4 from Keppas et al., (2017)].

Are these ice lollies important?

Ice lollies were observed more recently (September 2016) during another aircraft mission over the northeast Atlantic Ocean but no radar coverage supported the observations. At the moment of writing this article, the lack of observations prevent us from determining the importance of these ice lollies in the climate system. However, future missions would provide more insight. In the meantime, we suggest you to enjoy a lollipop such as the one shown in the image of this week 🙂

This is a joint post, published together with the Cryospheric division blog, given the interdisciplinarity of the topic.

Edited by Sophie Berger and Dasaraden Mauree

Reference/Further reading

Keppas, S. Ch., J. Crosier, T. W. Choularton, and K. N. Bower (2017), Ice lollies: An ice particle generated in supercooled conveyor belts, Geophys. Res. Lett., 44, doi:10.1002/2017GL073441

 


DavidDavid Docquier is a post-doctoral researcher at the Earth and Life Institute of Université catholique de Louvain (UCL) in Belgium. He works on the development of processed-based sea-ice metrics in order to improve the evaluation of global climate models (GCMs). His study is embedded within the EU Horizon 2020 PRIMAVERA project, which aims at developing a new generation of high-resolution GCMs to better represent the climate.

Black Carbon: the dark side of warming in the Arctic

Black Carbon: the dark side of warming in the Arctic

When it comes to global warming, greenhouse gases – and more specifically CO2 – are the most often pointed out. Fewer people know however that tiny atmospheric particles called ‘black carbon’ also contribute to the current warming. This post presents a paper my colleague and I recently published in Nature Communications . Our study sheds more light into the chemical make-up of black carbon, passing through the Arctic.


Black Carbon warms the climate

 Figure 1: Global radiative forcing of CO2 (green) compared to black carbon (blue). The colored bars show the mean change in radiative forcing due to the concentration of CO2 and BC in the atmosphere. The estimated range for the expected radiative forcing is everything between the white lines, which show the 90% confidence interval. (Data according to Boucher et al. 2013 (IPCC 5th AR) and Bond et al. 2013). [Credit: Patrik Winiger]

Figure 1: Global radiative forcing of CO2 (green) compared to black carbon (blue). The colored bars show the mean change in radiative forcing due to the concentration of CO2 and BC in the atmosphere. The estimated range for the expected radiative forcing is everything between the white lines, which show the 90% confidence interval. (Data according to Boucher et al. 2013 (IPCC 5th AR) and Bond et al. 2013). [Credit: Patrik Winiger]

Black Carbon (BC) originates from incomplete combustion caused by either natural (e.g., wild fires) or human (e.g., diesel car emissions) activities. As the name suggests, BC is a dark particle which absorbs sunlight very efficiently. In scientific terms we call this a strong positive radiative forcing, which means that the presence of BC in the atmosphere is helping to heat the planet. Some estimates put its radiative forcing in second place, only after CO2 (Figure 1). The significant thing about BC is that it has a short atmospheric lifetime (days to weeks), meaning we could quickly avoid some climate warming by getting rid of its emissions. Currently global emissions are increasing year by year and on snow and ice, the dark particles have a longer lasting effect due to the freeze and thaw cycle, where BC can re-surface, before it is washed away. It is important however to note, that our main focus on emission reduction should target (fossil-fuel) CO2 emissions, because they will affect the climate long after (several centuries) they have been emitted.

Arctic amplification: strongest warming in the North Pole

The Arctic is warming faster than the rest of our planet. Back in 1896, the Swede Arrhenius, (better known for his works: in chemistry), calculated, that a change in atmospheric CO2 – which at that time was a good 100 ppm lower than today – would change the temperature at higher latitudes (towards the poles) more than at lower latitudes.

Figure 2: Observation based global surface temperature anomalies for Jan-Mar (2016) in °C with respect to a 1961-1990 base year. Credit: GISTEMP Team, 2016: GISS Surface Temperature Analysis (GISTEMP). NASA Goddard Institute for Space Studies. Dataset accessed 2016-10-15 at http://data.giss.nasa.gov/gistemp/ [Hansen et al., 2010].

Figure 2: Surface temperature anomalies (in °C) for Jan-Mar (2016) with respect to a 1961-1990 baseline. [ Credit: NASA — GISTEMP (accessed 2016-10-15) and Hansen et al., 2010].

The problem with his calculations – as accurate and impressive they might have been – was, that he ignored the earth’s geography and seemed unaware of the big heat capacity of the oceans. On the southern half of our planet there is a lot more water, which can take up more heat, as compared to the northern half with more land surface. Thus, in reality the latitudes on the southern hemisphere have not heated as much as their northern counterparts and this effect came to be known as Arctic amplification.

Dark particles on bright snow and ice

Figure 3: Welcome to the Greenland Ice Sheet everybody. Probably an extreme case of ice covered in cryoconite, captured in August 2014 [Credit: Jason Box, (LINK: http://darksnow.org/)].

Figure 3: Ice covered in cryoconite, Greenland Ice Sheet, in August 2014 [Credit: Jason Box — Dark Snow project].

Greenhouse gases and BC are not the only reasons for the increase in temperature change and earlier onset of the melting season in the Arctic. Besides BC, there are other ‘light absorbing impurities’ such as dust, microorganisms, or a mixture of all of the above, better known as cryoconite. They all absorb solar radiation and thus decrease the albedo – the amount of solar energy reflected back to space – of the underlying white surface. This starts a vicious cycle by which these impurities melt the snow or ice and eventually uncover the usually much darker surface (e.g., rock or open sea water), leading to more solar absorption and the cycle continues. The effect and composition of these impurities are currently intensively studied on the Greenland ice sheet (check out the Black and Bloom, as well as the Dark Snow projects).

Black Carbon effect on climate is highly uncertain

One of the reasons for the high uncertainty of BC’s climate effects is the big range in effects it has (see white line on Figure 1), when it interacts with snow and ice (or clouds and the atmosphere).

Another source of uncertainty is probably the big estimated range in the global, and especially in the regional emissions of BC in the Arctic. For example, the emission inventory we work with (ECLIPSE), is based on international and national statistics that indicate how much of a certain fuel (diesel, coal, gas, wood, etc.) is used, and in which way it is used (vehicle sizes, machine type and age, operating conditions, etc.). These numbers can vary a lot. If we, for example, line up different emission inventories of man-made emissions (Figure 4), by comparing the two different fractions of BC (fossil fuels vs. biomass burning) at different latitudes, then we see that the closer we get to the North pole, the more these emission inventories disagree. And this is still ignoring atmospheric transport or emissions of natural sources, such as wildfires.

Computer models, necessary to calculate global climate change, are partly based on input from these emission inventories. Models used for the calculation of the transport of these tiny particles have vastly improved in recent years, but still struggle at accurately mimicking the seasonality or extent of the observed BC concentrations. To some extent this is also due to the range of parametrization in the model, mainly the lifetime of BC, including its removal from the atmosphere by wet scavenging (e.g., rain). So to better understand black carbon effects on climate, more model calculations are necessary, for which the emission inventory estimates need to be verified by observations.

Figure 4: Fraction biomass burning of BC (fbb) at different latitudes North, estimated by three different emission inventories. The green line shows the GAINS emission inventory, which was the precursor to the ECLIPSE inventory (Klimont et al. 2016) [Credit: Patrik Winiger]

Figure 4: Fraction biomass burning of BC (fbb) at different latitudes North, from three different emission inventories. The green line shows the GAINS emission inventory, which was the precursor to the ECLIPSE inventory (Klimont et al. 2016) [Credit: Patrik Winiger]

How do we trace the origin of black carbon?

This is where the science of my colleagues and me comes in. By looking at BC’s isotopic ratio of stable-carbon (12C/13C) and its radiocarbon (14C) content we were able to deduce information about the combustion sources (Figure 5).

Plants (trees) take up contemporary radiocarbon, naturally present in the atmosphere, by photosynthesis of atmospheric CO2. All living organisms have thus more or less the same relative amount of radiocarbon atoms, we talk of a similar isotopic fingerprint. BC from biomass (wood) burning thereby has a contemporary radiocarbon fingerprint.

When they die, organisms stop incorporating contemporary carbon and the radiocarbon atoms are left to decay. Radiocarbon atoms have a relative short (at least on geological time-scales) half-life of 5730 years, which means that fossils and consequentially BC from fossil fuels are completely depleted of radiocarbon. This is how the measured radiocarbon content of a BC sample gives us information on the relative contributions of fossil fuels vs. biomass burning.

The stable carbon isotopic ratio gives information on the type of combustion sources (liquid fossil fuels, coal, gas flaring or biomass burning). Depending on how a certain material is formed (e.g., geological formation of coal), it has a specific isotopic ratio (of 12C/13C), like a fingerprint. Sometimes isotopic fingerprints can be altered during transport (because of chemical reactions or physical processes like condensation and evaporation). However, BC particles are very resistant to reactions and change only very little. Hence, we expect to see the same fingerprints at the observation site and at the source, only that the isotopic signal at the observation site will be a mixture of different source fingerprints.

Figure 5/ Carbon isotopic signatures of different BC sources, summarized by E.N. Kirillova (2013).

Figure 5: Carbon isotopic signatures of different BC sources, summarized by E.N. Kirillova (2013). To give information about the isotopic fingerprint, the delta-notation is used (small delta for 12C/13C, and big delta for 12C/14C). The isotopic values show how much a certain sample is different, on a per mil scale, from an international agreed isotopic standard value (or ratio) for carbon isotopes. [Credit: fig 1 from Kirillova (2013)]

Where does the black carbon in European Arctic come from?

In our study (Winiger et al, 2016), we observed the concentrations and isotopic sources of tiny particles in airborne BC for over a year, in the European Arctic (Abisko, Sweden), and eventually compared these observations to model results, using the freely available atmospheric transport model FLEXPART and emission inventories for natural and man-made BC emissions.

Seeing our results we were first of all surprised at how well the model agreed with our observations. We saw a clear seasonality of the BC concentrations, like it has been reported in the literature before, and the model was able to reproduce this. Elevated concentrations were found in the winter, which is sometimes referred to as Arctic haze. The combustion sources showed a strong seasonality as well. The radiocarbon data showed, that fossil fuel combustion dominated in the winter and (wood) biomass burning during the low BC-burden periods in the summer. With a combination of the stable isotope fingerprints and Bayesian statistics we further concluded, that the major fossil fuel emissions came from liquid fossil fuels (most likely diesel). The model predicted a vast majority of all these BC emissions to be of European origin. Hence, we concluded, that the European emissions in the model had to be well constrained and the model parametrization of BC lifetime and wet-scavenging had to be fairly accurate for the observed region and period. Our hope is now that our work will be implemented in future models of BC effects and taken into account for future BC mitigation scenarios.

Figure 6: This is an example from the model calculations, showing where the (man-made) BC came from in January 2012. Abisko's position is marked as a blue star. The darker (red) spots show sources of higher BC contribution. This winter example was among the three highest observed (in terms of BC concentration) and the sources were ~50% wood burning, ~20% liquid fossil fuels (diesel) and ~30% coal. Some of the darkest spots can clearly be attributed to European cities.

Figure 6: Example from the model calculations, showing where the (man-made) BC came from in January 2012. Abisko’s position is marked as a blue star. The darker (red) spots show sources of higher BC contribution. This winter example was among the three highest observed (in terms of BC concentration) and the sources were ~50% wood burning, ~20% liquid fossil fuels (diesel) and ~30% coal. Some of the darkest spots can clearly be attributed to European cities. [Credit: fig4b from Winiger et al (2016)]

References

  • Anderson, T. R., E. Hawkins, and P. D. Jones (2016), CO2, the greenhouse effect and global warming: from the pioneering work of Arrhenius and Callendar to today’s Earth System Models, Endeavour, in press, doi:10.1016/j.endeavour.2016.07.002.
  • Arrhenius, S. (1896), On the influence of carbonic acid in the air upon the temperature of the ground., Philos. Mag. J. Sci., 41(August), 239–276, doi:10.1080/14786449608620846.
  • Hansen, J., R. Ruedy, M. Sato, and K. Lo (2010), Global surface temperature change, Rev. Geophys., 48(4), RG4004, doi:10.1029/2010RG000345.
  • Klimont, Z., Kupiainen, K., Heyes, C., Purohit, P., Cofala, J., Rafaj, P., Borken-Kleefeld, J., and Schöpp, W.: Global anthropogenic emissions of particulate matter including black carbon, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2016-880, in review, 2016.
  • Kirillova, Elena N. “Dual isotope (13C-14C) Studies of Water-Soluble Organic Carbon (WSOC) Aerosols in South and East Asia.” (2013). ISBN 978-91-7447-696-5 pp. 1-37
  • Winiger, P., Andersson, A., Eckhardt, S., Stohl, A., & Gustafsson, Ö. (2016). The sources of atmospheric black carbon at a European gateway to the Arctic. Nature Communications, 7.

Edited by Sophie Berger, Dasaraden Mauree and Emma Smith
This is joint post with the Cryospheric Division , given the interdisciplinarity of the topic featured.


portraitPatrik Winiger is a PhD student at the Department of Environmental Science and Analytical Chemistry and the Bolin Centre for Climate Research, at Stockholm University. His research interest focuses on impact and mitigation of Short Lived Climate Pollutants and anthropogenic CO2 emissions. Currently he investigates the sources of black carbon aerosols in the Arctic. He tweets as @PatrikWiniger

 

When cooling causes heating

When cooling causes heating

 

 

 

 

 

 

 

 

 

 

 

 

 

Following the Montreal Protocol in the late 1980s, CFC (chlorofluorocarbon) were replaced by hydrofluorocarbons (HFC) as a refrigerant. Unfortunately, the HFC’s have a global warming potential (GWP) far greater than the well-known greenhouse gas (GHG), carbon dioxide. Apart from the fact that this was not known until the mid-1990’s, climate-change due to GHG was not an emergency back then.

Rapid and urgent actions had to be undertaken in order to decrease the risk of temperature rise due to GHG. The COP21 held in Paris last year and the ratification by a majority of countries (and GHG emitters) has been followed by a landmark deal to eliminate HFC’s. It was concluded mid-October in Kigali where 197 states were meeting on the occasion of the 28th Montreal Protocol meeting.

But, why do GHG emissions matters, anyway? GHG warm the Earth by absorbing energy and by reducing the amount that escapes in space. This is more commonly known as the greenhouse effect. Due to the naturally present GHGs, the Earth’s air temperature is on average around 15°C. However, the burning of fossil fuels as well as the emission of other GHG’s from human activities are increasing this effect and causing a significant increase in the temperature (see Figure 1).

Figure 1: Left: Global CO2 emissions (US DoE) and  Right: Global land and ocean temperature anomalies (NOAA)

Figure 1: Left: Global carbon emissions (US DoE) and Right: Global land and ocean temperature anomalies (NOAA)

Going back to the HFC’s, scientists have argued that with the current rate of installation of air conditioning systems, there will be an overall 1.6 Billion units installed by 2050. With their booming economy, developing countries, like China or India, have experienced in the recent years a dramatic increase in such installation.

The deal that has been struck last week will have developed countries gradually decrease their HFC emissions as from 2019 while developing countries will start to decrease their emissions by 2024 (2028 for others). It has been argued that these emissions would have been responsible of 0.5°C rise air temperature by the end of 2100 (Xu et al., 2013). This is a significant contribution to the 1.5°C target set by the COP21.

A conversation with Didier Hauglustaine from the LSCE, France, however, highlighted the fact that there is no ideal replacement. One of the most promising one is the HFO. It looks like a variety of solutions will have to be developed depending on their usage. Giving some time to companies and states to adapt and develop new technologies that could replace HFC is hence a necessity.

All of this finally raises the question of the impact of man and new technologies on the atmosphere. It seems that we have created yet another problem while trying to resorb the ozone hole with the replacement of CFC by HFC’s. More importantly, the increase in air temperature, rapid urbanization as well as the higher probability of heat waves in the future, calls for an increased understanding of the urban environment. Human comfort (indoor and outdoor) in these areas should be assessed carefully at the design stage in order to develop new urban paradigms that could limit the use of air conditioning units.

Science Communication – Brexit, Climate Change and the Bluedot Festival

Science Communication – Brexit, Climate Change and the Bluedot Festival

Earlier this summer journalists, broadcasters, writers and scientists gathered in Manchester, UK for the Third European Conference of Science Journalists (ECSJ) arranged by two prestigious organisations. Firstly, the Association of British Science Writers (ABSW) who provides support to those who write about science and technology in the UK through debates, events and awards. Secondly the European Union of Science Journalists’ Associations (EUSJA) who are responsible for representing 2,500 science journalists from 23 national associations in 20 European countries. EUSJA promotes scientific and technical communication between the international scientific community and journalists. This is mainly by organising events, workshops and by working with the European Commission in the interest of Science and Society.

The pre-conference networking event began a towering twenty-three floors above the ground at the highest Champagne bar in Manchester. Here the delegates were introduced to the notion of Manchester as a hub for science with a fly-by video of the ‘science quarter’. This stems from the library at the heart of the city and fans outwards to the south like a segment in an orange. This segment engulfs an impressive two universities, several hospitals and a science park.

Looking towards the south west of the city from "Cloud 23", the bar on the 23rd floor of the Beetham Tower, Manchester, UK. Image credit: David Dixon

Looking towards the south west of the city from “Cloud 23”, the bar on the 23rd floor of the Beetham Tower, Manchester, UK. Image credit: David Dixon

The following morning the conference began at the Manchester Conference Complex in the city-centre focussing on contemporary issues in science journalism and skills for professional development. The panellists and chairs were a mixture of academics and journalists, a range of nationalities and, with experience of the field of science communication. They were allowed to discuss a topic amongst themselves before the conversation was opened to all-comers.

The opening plenary began a discussion on how independent Europe’s science news is and how it can become hijacked by vested interests. For example, if a person writes a scientific story for a newspaper, are they biased by being paid by an external company to write that story? There was a consensus for openness in the funding process behind news stories so that the merits of the story lie in how impartial the writer is perceived to be as well as the content itself.

Although the second session of the day was focussed on the reporting of EU funded science (an 80 billion Euro question) it also gave delegates a chance to mention the elephant in the room – the Brexit. This is the will of a spectrum of people representing the whole political horseshoe for the UK to leave the EU. There was a feeling from the panel that the EU funding structure has allowed science to work on projects that are not just commercially viable in the short-term. The large benefit of cross-country collaboration in Europe was stressed repeatedly. This related to the general acknowledgement that in research the country of origin of specific researchers becomes irrelevant. These thoughts played into the much discussed post-Brexit question(s) – Will it be harder in time for the UK to access EU science funding given its determination to curb net migration and what exemptions (from the UK and EU) can be made for experts in their field? It was also discussed how the UK’s pot of EU science funding may be allowed to be divided up amongst other EU countries in the future. The discussion ended with a series of brief historical anecdotes of governments who favoured local policies/competition which have had a tendency to derail international collaboration. The main point being that research continued but the job was made harder.

The next two sessions focussed on starting a new publication and pitching your idea to an existing publication (sales idea). Using the case-studies of a range of recent start-up publications it was decided that what matters most for creating a publication is: focus, editorial quality, being online, design, collaboration and content.

The closing plenary was concerned with how to work for media that are sceptical about climate change – a place where a science communicator may be forced to go along with the editorial line against their own conviction. A conviction shared by the majority of scientists world-wide who say climate change is happening but argue over the rate that it is occurring. A good recommendation was not to preach but to state facts. The dangers of saying something sceptical as a way into the topic were debated. It was thought that this may backfire if the sceptical comment is later quoted as an expert opinion. At the end of the session the delegates pondered that if the building blocks of climate change were first conceived in 1896 how it is amazing to think that this topic is still controversial 120 years later!

For the final event of the day, the delegates made their way to the Bluedot festival at Jodrell Bank – a festival of music, science, arts, technology, culture, food and film in the shadow of the Lovell Telescope which was illuminated by Brian Eno using large scale projections to create a visual installation. Here the ABSW Science Writers’ Awards was hosted and this blog was short-listed for an award. It provided another great opportunity to network at this thought-provoking conference.

Final