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Imaggeo

Imaggeo on Mondays: Mountains, rivers and agriculture

This week’s Imaggeo on Mondays image blends a range of geoscience disciplines. The post, by Irenen Mazoff, a researcher at Johann Wolfgang Goethe-Universitaet, explores how the mountains, rivers and soils of the High Atlas in Morocco are intrinsically linked to the agriculture of the region.

High Atlas landscape. Credit: Irene Marzolff (distributed via imaggeo.egu.eu)

High Atlas landscape. Credit: Irene Marzolff (distributed via imaggeo.egu.eu)

The image was taken in the southern slopes of the Western High Atlas, north of the city of Taroudannt. The snow of these mountains, which in April is still prevailing on the highest ranges in the background of the photo, is a significant water resource for the region. The high interannual variability of precipitation and its changing patterns associated to climate change present a serious challenge for natural environment and for the sustainable use of water as a resource in agriculture and tourism, the two major economic sectors in the area.

A characteristic open cover of Argan trees (Argania spinosa) can be seen on the lower mountain slopes in the middle distance of the photo: an endemic species with small, oil-rich fruits resembling olives that yield high-quality oil used in medicine, food and cosmetics. The species is a relic of the Tertiary (66 to 2.8 million years ago) but has been under threat from human exploitation for centuries, by excessive grazing, fire-wood cutting, charcoal making and changes to the groundwater table. The area is part of the UNESCO-MAB Biosphere Reserve “Arganeraie” committed to the preservation and sustainable use of the trees.

The river bed in the foreground is formed by fluvial processes typical for this high-mountain region, with highly variable seasonal discharges controlled both by rainfall and snowmelt. It will in the near future drain into the Sidi Abdellah Reservoir that is currently being constructed near Tamaloukt. This reservoir will add to the 10 already existing water storage lakes in the region of Souss Massa Drâa, which is in urgent need of additional water resources: The Souss Valley to the South of the High Atlas is one of Morocco’s most intensely farmed agricultural regions, with agro-industrial production of bananas, vegetables and citrus fruit. Much of this, including 90% of Morocco’s tomato production, is exported to the European market.

By Irene Marzolff, researcher at the Institut fuer Physische Geographie, Johann Wolfgang Goethe-Universitaet, Frankfurt.

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: Strombolian eruption

Imaggeo on Mondays: Strombolian eruption

Jonas Kuhn, a researcher at Heidelberg University , took the photograph during a field campaign at Stromboli volcano in Italy. The objective of this campaign was to gather data from different gaseous compounds of the volcanic plume. Via emission fluxes of volcanic gases (e.g. SO2, CO2, halogen compounds…) or the ratio of emitted gases, one can retrieve information about the interior of the volcano and magma dynamics. Volcanic gas measurements can therefore contribute to better understanding volcanoes and in predict volcanic activity.

There are several ways in which scientists can gather information about volcanic processes from plume gas measurements. Let’s start by taking a look at sulphur dioxide, as it is emitted by volcanoes in large amounts. A relatively novel measurement instrument, the SO2 Camera, is able to record 2D SO2 distributions with a high time resolution. This means that SO2 emission fluxes can be determined and linked to other volcanological data sets as e.g. seismic data or simply to the occurrence of explosions. The high resolution SO2 emission fluxe data can give insight into the footprints of volcanic processes like the bursting of gas bubbles in the magma. So depending on e.g. the viscosity of the magma one would expect different frequencies in the emission flux of different volcanoes.

“In our group, a lot of work was done on further developing such camera systems. In volcanology this technique has only been applied for the past decade,” explains Jonas.

Another innovative device for fast optical in situ measurement of SO2 andCO2, as well as chemical in situ measurements of halogen compounds in the plume was also tested during the field trip. By using the ratios of other gases to SO2 and the known SO2 flux (from the SO2 camera measurement), fluxes of the other gases can be estimated. Different gases have different solubilities in magma, so they are released from the magma at different pressures.  Ratios of gas abundances in the volcanic plume can therefore contain information on, for instance, changes in the magma level (it’s not uncommon for magma to be ‘invisible’ in the interior of the volcano). The magma level can also be a crucial indicator of volcanic activity.

“What made this field campaign special was that relatively new and young volcanic measurement techniques were tested and used,” outlines Jonas, who goes on to point out ““many of them are still in the development stages. The volcanic gas measurement field is very exciting at this time. Interesting insights have been gained in the last decades and there is still a lot of ideas and new technologies coming up.”

By Jonas Khun,  Researcher at Heidelberg University and Laura Roberts Artal, EGU Communications Officer

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: The place where water runs through rocks

Imaggeo on Mondays: The place where water runs through rocks

Antelope Canyon, located in Arizona, USA, was formed by erosion of the Navajo Sandstone, primarily due to flash flooding and secondarily due to other sub-aerial processes (think of physical weathering processes such as freeze-thaw weathering exfoliation and salt crystallisation). Rainwater runs into the extensive basin above the slot canyon sections, picking up speed and sand as it rushes into the narrow passageways. Over time the passageways are eroded away, making the corridors deeper and smoothing hard edges in such a way as to form characteristic ‘flowing’ shapes in the rock.

The Navajo Sandstone was deposited in an aeolian (wind-blown) environment composed of large sand dunes: imagine a sea of sand, or an erg, as it is known scientifically, not dissimilar to the present Sarah desert landscape. The exact age of the Navajo Sandstone is controversial, with dated ages ranging from Triassic to early Jurassic, spanning a time period between 250 million years ago to approximately 175 million years ago. The difficulty in determining the exact age of the unit lies in its lack of age diagnostic fossils. The Navajo Sandstone is not alone in this quandary, dating is a common problem in aeolian sediments.

“The picture was taken during a three week Southwest USA road trip in summer 2012. One of the highlights was the visit to Antelope slot canyon, which is located on Navajo land east of Page, Arizona. The Navajo name for Upper Antelope Canyon is Tsé bighánílíní, which means the place where water runs through rocks,” explains Frederik Tack, an atmospheric scientist from the Belgian Institute for Space Aeronomy and author of today’s Imaggeo on Monday’s photograph.

The erosive processes which form the canyon are still ongoing. There is an elevated risk of flash floods, meaning the canyon can only be visited as part of guide tours.

“The canyon was actually quite crowded which made taking this picture challenging, especially as I wanted to capture the peace and solitude of the landscape,” describes Tack.

The effort was worth it: Waved rocks of Antelope slot canyon was one of the EGU’s 2015 Photo Contest finalists!

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: Late Holocene Fever

Imaggeo on Mondays: Late Holocene Fever

A huge ice fall off the Perito Moreno glacier in the Los Glaciares National Park, southwest Santa Cruz Province, Argentina, was voted one of the three best pictures entered into the EGU’s annual photo contest, by the conference participants at the 2015 General Assembly.

Perito Moreno glacier is one of 48 glaciers feeding into the Southern Patagonia ice field, which combined with the Northern Patagonia ice field, comprise the largest temperate ice mass in the Southern Hemisphere. Like many other mountain glaciers, Perito Moreno, is highly sensitive to climate change. At the surface of a glacier, erosive processes know as ablation, can remove ice from the bulk of the glacial mass. If the ice lost is not replaced in sufficient quantities by rainfall and snow provided by weather systems, the energy balance of the glacier is upset and the glacier starts to shrink. At the glacial surface, the processes of accumulation and ablation, clearly manifest the strict connection between glaciers and climate.

In a recent interview, Bernard Francou, a renowned French glaciologist, explained that glacier depletion in the Andes region has increased dramatically in the second half of the 20th century. In recent decades the glacier recession rates increased at an unprecedented rate when compared to the last the last three centuries. It is estimated that glaciers in this region have lost between 35% and 50% of their area and volume since 1976.

Christian Massari, a hydrology postdoctoral researcher of the Italian National Research Council, says “capturing the precise moment when the large chunk of ice broke off the glacier front was not easy task. It required concentration to patiently wait two hours, on a hot January day, to capture the critical moment.”

You can watch a video of a similar ice fall event, which took place in January 2012, here.

Southern Patagonia Ice Field. Credit: Astronaut photograph ISS038-E-47324 was acquired on February 13, 2014, with a Nikon D3S digital camera using a 65 millimeter lens, and is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center. The image was taken by the Expedition 38 crew. It has been cropped and enhanced to improve contrast, and lens artifacts have been removed.

Southern Patagonia Ice Field . Credit: Astronaut photograph ISS038-E-47324 was acquired on February 13, 2014, with a Nikon D3S digital camera using a 65 millimeter lens, and is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center. The image was taken by the Expedition 38 crew. It has been cropped and enhanced to improve contrast, and lens artifacts have been removed. (Distributed via Nasa Earth Observatory, Image of the Day ).

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/.

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