GeoLog

Regular Features

Photo Contest finalists 2017 – who will you vote for?

The selection committee received over 300 photos for this year’s EGU Photo Contest, covering fields across the geosciences. The fantastic finalist photos are below and they are being exhibited in Hall X2 (basement, Brown Level) of the Austria Center Vienna – see for yourself!

Do you have a favourite? Vote for it! There is a voting terminal (also in Hall X2), just next to the exhibit. The results will be announced on Friday 28 April during the lunch break (at 12:15).

Imaggeo on Mondays: In the belly of the beast

In the belly of the beast . Credit: Alexandra Kushnir (distributed via imaggeo.egu.eu)

Conducting research inside a volcanic crater is a pretty amazing scientific opportunity, but calling that crater home for a week might just be a volcanologist’s dream come true, as Alexandra postdoctoral researcher at the Institut de Physique du Globe de Strasbourg, describes in this week’s Imaggeo on Mondays.

This picture was taken from inside the crater of Mount St Helens, a stratovolcano in Washington State (USA). This particular volcano was made famous by its devastating explosive eruption in 1980, which was triggered by a landslide that removed most of the volcano’s northern flank.

Between 2004 and 2008 Mount St Helens experienced another type of eruption – this time effusive (where lava flowed out of the volcano without any accompanying explosions). Effusive eruptions produce lava flows that can be runny (low-viscosity) like the flows at Kilauea (Hawaii) or much thicker (high viscosity) like at Mount St Helens. Typically, high viscosity lavas can’t travel very far, so they begin to clump up in and around the volcano’s crater forming dome-like structures.  Sometimes, however, the erupting lava can be so rigid that it juts out of the volcano as a column of rock, known as a spine.

The 2004 to 2008 eruption at Mount St Helens saw the extrusion of a series of seven of these spines. At the peak of the eruption, up to 11 meters of rock were extruded per day. As these columns were pushed up and out of the volcanic conduit – the vertical pipe up which magma moves from depth to the surface – they began to roll over, evoking images of whales surfacing for air.

‘Whaleback’ spines are striking examples of exhumed fault surfaces – as these cylinders of rock are pushed out of the volcano their sides grind against the inside of the volcanic conduit in much the same way two sides of a fault zone move and grind past each other. These ground surfaces can provide scientists with a wealth of information about how lava is extruded during eruption. However, spines are generally unstable and tend to collapse after eruption making it difficult to characterize their outer surfaces in detail and, most importantly, safely.

Luckily, Mount St Helens provided an opportunity for a group of researchers to go into a volcanic crater and characterise these fault surfaces. While not all of the spines survived, portions of at least three spines were left intact and could be safely accessed for detailed structural analysis. These spines were encased in fault gouge – an unconsolidated layer of rock that forms when two sides of a fault zone move against one another – that was imprinted with striations running parallel to the direction of extrusion, known as slickensides. These features can give researchers information about how strain is accommodated in the volcanic conduit. The geologist in the photo (Betsy Friedlander, MSc) is measuring the dimensions and orientations of slickensides on the outer carapace of one of the spines; the southern portion of the crater wall can be seen in the background.

Volcanic craters are inherently changeable places and conducting a multi-day field campaign inside one requires a significant amount of planning and the implementation of rigorous safety protocols. But above all else, this type of research campaign requires an acquiescent mountain.

Because a large part of Mount St Helens had been excavated during the 1980 eruption, finding a safe field base inside the crater was possible. Since the 2004-2008 deposits were relatively unstable, the science team set up camp on the more stable 1980-1986 dome away from areas susceptible to rock falls and made the daily trek up the eastern lobe of the Crater Glacier to the 2004-2008 deposits.

Besides being convenient, this route also provides a spectacular tableau of the volcano’s inner structure with its oxidized reds and sulfurous yellows. The punctual peal of rock fall is a reminder of the inherent instability of a volcanic edifice, and the peculiar mix of cold glacier, razor sharp volcanic rock, and hot magmatic steam is otherworldly. That is, until an errant bee shows up to check out your dinner.

By Alexandra Kushnir, postdoctoral researcher at the Institut de Physique du Globe de Strasbourg, France.

This photo was taken in 2010 while A. Kushnir was a Masters student at the University of British Columbia and acting as a field assistant on the Mount St Helens project.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

 

Imaggeo on Mondays: Atmospheric gravity waves

Imaggeo on Mondays: Atmospheric gravity waves

From the tiny vibrations which travel through air, allowing us to hear music, to the mighty waves which traverse oceans and the powerful oscillations which shake the ground back and forth during an earthquake, waves are an intrinsic part of the world around us.

As particles vibrate repeatedly, they create an oscillation, which when accompanied by the transfer of energy, creates a wave.  The way in which waves travel varies hugely. Take for instance a ripple in a pond: vibrations there are perpendicular to the direction in which the wave is travelling – transverse waves. When a slinky moves (or sound waves), on the other hand, vibrations happen in the same direction in which the wave travels – longitudinal waves. Ocean waves are more complex. The motion there combines surface waves, created by the friction between wind and surface water, and the energy passing through the water causes it to move in a circular motion. With a little imagination, it’s not so difficult to visualise these different phenomena.

But not all waves on Earth are so intuitive.

Unlike the waves we’ve discussed up until now, internal gravity waves oscillate within a fluid medium, rather than on its surface. In the Earth’s atmosphere, internal gravity waves transfer energy from the troposphere (the layer closest to the Earth’s surface) to the stratosphere (where the ozone layer is found) to the very cold mesosphere, which starts some 50 km away from the planet’s surface. They are usually created at weather fronts: the boundary where two pockets of air at different temperatures and humidity meet. Air flowing over mountains can also generate them.

Because they propagate across layered fluids (the different layers of the atmosphere, for example), internal gravity waves can be responsible for transferring considerable amounts of energy over large distances, which is one of the main reasons why they are important in atmospheric and ocean dynamics.

But only with improved satellite and remote sensing technologies have scientists been able to observe them clearly. Today’s featured image is a great example of one such wave.  It was acquired by the European Space Agency’s Envisat satellite (which aimed to carry out the largest civilian Earth observation mission to date – launched in 2002), on September 16th 2004.

A short animation showing just how impressive these waves are when travelling across the Mozambique Channel – using data from the Meteosat 5 satellite. (Credit: Jorge Magalhaes and Jose da Silva)

The image covers an area of about 580 by 660 km and was acquired as the satellite flew over the Mozambique Channel. The two-dimensional horizontal structure of a very large-scale atmospheric internal wave can be seen in the center of the image travelling southwest. The crest length of the leading wave, in this case, extends for more than 500 km and its crest-to-crest spatial scale is approximately 10 km on average.

It is interesting to note that several (but not all) of these individual waves are made visible by characteristic cloud bands, which form as the vertical oscillations find the necessary conditions (high moisture in the atmosphere) for condensation to occur.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

GeoTalk: How are clouds born?

GeoTalk: How are clouds born?

Geotalk is a regular feature highlighting early career researchers and their work. In this interview we speak to Federico Bianchi, a researcher based at University of Helsinki, working on understanding how clouds are born. Federico’s quest to find out has taken him from laboratory experiments at CERN, through to the high peaks of the Alps and to the clean air of the Himalayan mountains. His innovative experimental approach and impressive publication record, only three years out of his PhD, have been recognised with one of four Arne Richter Awards for Outstanding Early Career Scientists in 2017.

First, could you introduce yourself and tell us a little more about your career path so far?

I am an enthusiastic atmospheric chemist  with a passion for the mountains. My father introduced me to chemistry and my mother comes from the Alps. This mix is probably the reason why I ended up doing research at high altitude.

I studied chemistry at the University of Milan where I got my degree in 2009.  During my bachelor and master thesis I investigated atmospheric issues affecting the polluted Po’ Valley in Northern Italy and since then I have always  worked as an atmospheric chemist.

I did my PhD at the Paul Scherrer Institute in Switzerland where I mainly worked at the CLOUD experiment at CERN. After that, I used the acquired knowledge to study the same phenomena, first, at almost 4000 m in the heart of the Alps and later at the Everest Base Camp.

I did one year postdoc at the ETH in Zurich and now I have my own Fellowship paid by the Swiss National Science Foundation to conduct research at high altitude with the support of the University of Helsinki.

We are all intimately familiar with clouds. They come in all shapes and sizes and are bringers of shade, precipitation, and sometimes even extreme weather. But most of us are unlikely to have given much thought to how clouds are born. So, how does it actually happen?

We all know that the air is full of water vapor, however, this doesn’t mean that we have clouds all the time.

When air rises in the atmosphere it cools down and after reaching a certain humidity it will start to condense and form a cloud droplet. In order to form such a droplet the water vapor needs to condense on a cloud seed that is commonly known as a cloud condensation nuclei. Pure water droplets would require conditions that are not present in our atmosphere. Therefore, it is a good assumption to say that each cloud droplet contains a little seed.

At the upcoming General Assembly you’ll be giving a presentation highlighting your work on understanding how clouds form in the free troposphere. What is the free troposphere and how is your research different from other studies which also aim to understand how clouds form?

The troposphere, the lower part of the atmosphere, is subdivided in two different regions. The first is in contact with the Earth’s surface and is most affected by human activity. This one is called the planetary boundary layer, while the upper part is the so called free troposphere.

From several studies we know that a big fraction of the cloud seeds formed in the free troposphere are produced by a gas-to-particles conversion (homogeneous nucleation), where different molecules of unknown substances get together to form tiny particles. When the conditions are favourable they can grow into bigger sizes and potentially become cloud condensation nuclei.

In our research, we are the first ones to take state of the art instrumentation, that previously, had only been used in laboratory experiments or within the planetary boundary layer, to remote sites at high altitude.

Federico has taken state of the art instrumentation, that previously, had only been used in laboratory experiments or within the planetary boundary layer, to remote sites at high altitude. Credit: Federico Bianchi

At the General Assembly you plan on talking about how some of the processes you’ve identified in your research are potentially very interesting in order to understand the aerosol conditions in the pre-industrial era (a time period for when information is very scarce). Could you tell us a little more about that?

Aerosols are defined as solid or liquid particles suspended in a gas. They are very important because they can have an influence on the Earth’s climate, mainly by interacting with the solar radiation and cooling temperatures.

The human influence on the global warming estimated by the Intergovernmental Panel for Climate Change (known as the IPCC) is calculated based on a difference between the pre-industrial era climate indicators and the present day conditions. While we are starting to understand the aerosols present currently, in the atmosphere, we still know very little about the conditions before the industrial revolution.

For many years it has been thought that the atmosphere is able to produce new particles/aerosol only if sulphur dioxide (SO2) is present. This molecule is a vapor mainly emitted by combustion processes; which, prior to the industrial revolution was only present in the atmosphere at low concentrations.

For the first time, results from our CLOUD experiments, published last year,  proved that organic vapours emitted by trees, such as alpha-pinene, can also nucleate and form new particles, without the presence of SO2. In a parallel study, we also observed that pure organic nucleation can take place in the free troposphere.

We therefore have evidence that the presence of sulphur dioxide isn’t necessary to make such a mechanism possible. Finally, with all this new information, we are able to say that indeed, in the pre-industrial era the atmosphere was able to produce new particles (clouds seeds) by oxidation of vapors emitted by the vegetation.

Often, field work can be a very rewarding part of the research process, but traditional research papers have little room for relaying those experiences. What were the highlights of your time in the Himalayas and how does the experience compare to your time spent carrying out laboratory experiments?

Doing experiments in the heart of the Himalayas is rewarding. But life at such altitude is tough. Breathing, walking and thinking is made difficult by the lack of oxygen at high altitudes.

I have always been a scientists who enjoys spending time in the laboratory. For this reason I very much liked  the time I spent in CERN, although, sometimes it was quite stressful. Being part of such a large international collaboration and being able to actively do science was a major achievement for me. However, when I realized I could also do what I love in the mountains, I just couldn’t  stop myself from giving it a go.

The first experiment in the Alps was the appetizer for the amazing Himalayan experience. During this trip, we first travelled to Kathmandu, in Nepal. Then, we flew to Luckla (hailed as one of the scariest airport in the world) and we started our hiking experience, walking from Luckla (2800 m) up to the Everest Base Camp (5300 m). We reached the measurement site after a 6 days hike through Tibetan bridges, beautiful sherpa villages, freezing nights and sweaty days. For the whole time we were surrounded by the most beautiful mountains I have ever seen. The cultural element was even more interesting. Meeting new people from a totally different culture was the cherry on the cake.

However I have to admit that it was not always as easy as it sounds now. Life at such altitude is tough. It is difficult to breath, difficult to walk and to install the heavy instrumentation. In addition to that, the temperature in your room during nights goes well below zero degrees. The low oxygen doesn’t really help your thinking, especially we you need to troubleshoot your instrumentation. It happens often that after such journey, the instruments are not functioning properly.

I can say that, as a mountain and science lover, this was just amazing. Going on a field campaign is definitely the  best part of this beautiful job.

To finish the interview I wanted to talk about your career. Your undergraduate degree was in chemistry. Many early career scientists are faced with the option (or need) to change discipline at sometime throughout their studies or early stages of their career. How did you find the transition and what advice would you have for other considering the same?

As I said before, I studied chemistry and by the end of my degree my favourite subject moved to atmospheric chemistry. The atmosphere is a very complex system and in order to study it, we need a multidisciplinary approach. This forced me to learn several other aspects that I had never been in touch with before. Nowadays, I still define myself as a chemist, although my knowledge base is very varied.

I believe that for a young scientist it is very important to understand which are his or her strengths and being able to take advantage of them. For example, in my case, I have used my knowledge in chemistry and mass spectrometry to try to understand the complex atmospheric system.

Geotalk is a regular feature highlighting early career researchers and their work.

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