GeoLog

Imaggeo

Imaggeo on Mondays: The waxing Earth

Imaggeo on Mondays: The waxing Earth

These incredible images of Earth were acquired from the European MSG-2 satellite on July 21, 2009. The MSG, which stands for Meteosat Second Generation, satellites are operated as a series of satellites which continually orbit our planet, capturing detailed images of Europe, Africa and parts of the Atlantic and Indian Ocean every 15 minutes. The data acquired is largely used by meteorologists.

The satellites operate in a geostationary orbit. This means they are located some 36000km above the equator and follow the Earth’s rotation. This orbit allows an extraordinary view on the waxing Earth at 5:00, 6:00, 7:00, 8:00, 10:00, and 12:00 UTC.

But what causes this periodicity ? Exploring the phases of our Moon over the period of approximately a month helps us visualise this phenomenon. It takes the Moon 27 days to complete a full revolution around Earth. During this time, the relative position between the Moon, Earth and the Sun changes, so that, seen from the Earth’s perspective, a new, waxing, full Moon, and waning Moon. Similarly, from the perspective of a geostationary satellite, the Earth apparently orbits the satellite once per day and likewise it observes a “new Earth”, “waxing Earth”, “full Earth”, and “waning Earth” once per day.

Interestingly, the MSG satellites have only one channel (covering the full earth disk) in the visible spectral region, in other words, the portion of the electromagnetic spectrum that is visible to the human eye. The human eye has receptors for three different colours, which means information is missing to generate true colour composite images from MSG. For this reason, Maximillian Reuter (a researcher at Institute of Environmental Physics, University of Bremen, in Germany) and Susanne Pfeifer (Climate Service Center Germany) developed an algorithm that primarily uses the SEVIRI (the main instrument aboard MSG) channels at 0.6μm, 0.8μm and 1.6μm, to transform RGB (red/green/blue) false colour composite images of the used channels into (quasi) true color images. The result is today’s featured image. The lack of information in the blue and green parts of the visible spectrum is compensated by using data from NASA’s Blue Marble next generation project.

By Maximillian Reuter, researcher at Institute of Environmental Physics, University of Bremen and Laura Roberts, EGU Communications Officer.

References :

More information in the publication M. Reuter, S. Pfeifer: Moments from space captured by MSG SEVIRI. International Journal of Remote Sensing, 32, 14, 4131-4140, doi: 10.1080/01431161.2011.566288,2011.

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: a big thank you from the EGU

Outside EGU General Assembly 2016. Credit: Kai Boggild/EGU (distributed via imaggeo.egu.eu)

The past week in Vienna was a busy one! Hordes of Earth, ocean and planetary scientists came together to present, share and discuss their most recent scientific findings at the 2016 General Assembly.

The conference was a great success, with over 4800 oral and 10300 poster presentations, as well as close to a 1000 PICO presentations too! Participants at the conference could pick talks and posters from a staggering selection of over 600 scientific sessions, as well as in excess of 300 side events. The programme in 2016 was indeed rich and varied! Helping participants choose from the vast selection of science on offer, 15,000 copies of EGU Today were distributed throughout the week.

The conference was attended by 13,650 scientists from 109 countries, of which 25% were students and 53% early career scientists (under the age of 35 years). There was also a keen media presence and reporting, and thousands of visits to the webstreams as well as to GeoLog.

We thank all of you very much for your attendance and your active contribution to this great event.

We look forward to seeing you all next year! The EGU General Assembly is back from 23–28 April 2017 in Vienna, Austria.

At the Assembly: Thursday highlights

At the Assembly: Thursday highlights

Welcome to the fourth day of General Assembly excitement! Once again the day is packed with great events for you to attend and here are just some of the sessions on offer. You can find out more about what’s on in EGU Today, the daily newsletter of the General Assembly – grab a copy on your way in or download it here.

The Union-wide session of the day focuses on deep geofluids as the bringers of change (US2). The physics, chemistry and biology of subsurface fluids will de addresses in a series of talks. Discover more from 15:30­–19:00 in l6.

Thursday sees the final two lectures in the series celebrating this year’s conference theme: Active Planet.  From 13:30, François Forget (Institut Pierre Simon Laplace) will talk about other active worlds in the solar system. (TL5: 13:30 – 15:00 / Room 0.93). Immediately after you can enjoy a talk about The Active Liquid Earth (TL:3: 15:30 – 17:00 / Room 0.93) highlighting the importance of considering temporal and spatial variability of the liquid Earth.

Thursday also sees another interesting Great Debate take place: Public peer review in open access publications, pros and cons (GDB, from 15:30–17:00 in E1). In public peer review, papers submitted to a peer-review journal are first published in a public discussion forum. The aim is to foster scientific discussion by making public review more transparent. But the system has its critics.  Join the debate! Tune into to the session on Twitter using the #EGU16GDB hashtag or online at http://www.egu2016.eu/webstreaming.html.

Today’s interdisciplinary highlights include sessions on…

Take the opportunity to expand your skills in one of today’s short courses and splinter meetings. Be sure to share what you learn on social media using the hashtag #EGU16SC:

A few of last year's awardees with the EGU President and Vice-President at the EGU 2015 Awards Ceremony. (Credit: EGU/Foto Pfluegl)

A few of last year’s awardees with the EGU President and Vice-President at the EGU 2015 Awards Ceremony. (Credit: EGU/Foto Pfluegl)

There’s also a number of Medal Lectures on throughout the day – here’s a sample of what’s on offer:

What have you thought of the Assembly so far? Let us know at www.egu2016.eu/feedback, and share your views on what future EGU meetings should be like!

If you need a change of pace, stop by the Imaggeo Photo Exhibition beside the EGU Booth (Hall X2, basement, Brown Level). You can vote for your favourite finalists there and – while you’re in the area – take the opportunity to meet your Division’s representatives in today’s Meet EGU appointments. While on the subject of competitions, make sure to ‘like’ your favourite  Communicate Your Science Video Competition film on the EGU YouTube channel.

Have a lovely day!

Imaggeo on Mondays: recreating geological processes in the lab

Imaggeo on Mondays: recreating geological processes in the lab

Many of the processes which take place on Earth happen over very long time scales, certainly when compared to the life span of a person. The same is true for geographical scale. Many of the processes which dominate how our planet behaves are difficult to visualise given the vast distances (and depths) over which they occur.

To overcome this difficulty, scientists have developed and resorted to a number of tools; from geological mapping right through to generating computer models. One such tool dates back some two centuries: analogue experiments. Initially they started off as roughly scaled experiments to test a range of hypothesis. Famously, James Hutton used analogue models to prove that the folding of originally horizontal strata is the result of lateral compression. With time they have become increasingly sophisticated, allowing researchers to replicate a vast range of conditions and environments which lead to a better understanding of how our planet works.

Today’s Imaggeo on Monday’s image, by Stephane Dominguez, a researcher Chargé de Recherche CNRS, in Montpellier, shows the final evolution stage of an analog experiment dedicated to the study of Relief Dynamics – how surface topography comes to be – and what role tectonics, erosion and sedimentation play in the formation of landscapes. In such experiments, typical scaling is 1cm = a few hundred meters and 1s = a few tens of years.

In this particular experiment “we used a specific granular material mixture (made of water saturated silica, microbeads, PVC and graphite powders, to simulate a portion of the upper terrestrial crust submitted to tectonic extension (where the crust is being stretched, such as at, but not limited to, continental rifts and divergent plate boundries),”explains Stephane.

At the same time, the research team used a rainfall system to project micro water droplets on the model surface. This causes water runoff to initiate and starts the growing reliefs to be eroded.

“We obtain a very realistic morphology that continuously evolves in response to complex interactions between surface deformation (induced by normal fault activity – caused by the stretching of the crust) and surface processes (erosion, sediment transport and deposition).”

 

References

Ranalli, G.: Experimental tectonics: from Sir James Hall to the present, Journal of Geodynamics, 32, 65-76.

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/.

Follow

Get every new post on this blog delivered to your Inbox.

Join other followers: