Posts by Neha Ganesh

Roundup: Calving, ‘Record grooves’ and Story Maps

Posted by on Mar 9, 2015 in All Posts, Featured Posts, News, Roundup, Science | 0 comments

Roundup: Calving, ‘Record grooves’ and Story Maps

Spread the News:Share Calved Greenland Iceberg  “Iceberg calving is ultimately related to the mechanical failure of ice. However, predicting mass loss from calving events remains challenging because calving takes on diferent forms under different conditions. For example, large tabular icebergs sporadically detach from freely foating ice tongues with many years of quiescence between major calving events” Read more on the physics of iceberg calving here.   Telling a Glacier Story through Maps   “Alaska Ice: Documenting Glaciers on the Move is an Esri Story Map which uses satellite imagery and comparisons of modern & vintage photographs to document Alaska’a glaciers.” Read more on ESRI’s Story Maps and Time-lapse here.   Linking Earth’s Ice Ages to Ocean Floor topography “The evidence comes from seafloor spreading centers: sites throughout the ocean where plates of ocean crust move apart and magma erupts in between, building new crust onto the plates’ trailing edges. Parallel to these spreading centers are “abyssal hills”: long, 100-meter-high ridges on the diverging plates, separated by valleys. On bathymetric maps of seafloor topography, they look like grooves on a record. These grooves, it now turns out, play the tune of Earth’s ice ages.” Read more on ‘Record grooves’ at Science.             Spread the...

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Photo Friday: Iceland’s Black Sand Beaches

Posted by on Mar 6, 2015 in All Posts, Featured Posts, Images | 0 comments

Photo Friday: Iceland’s Black Sand Beaches

Spread the News:ShareWhen a volcano erupts from underneath a glacier, pulses of meltwater deposit materials in outwash plains. The 1918 subglacial Katla volcano eruption in southern Iceland formed the Mýrdalssandur glacial outwash plain. This plain, which covers hundreds of square kilometers, includes a number of striking  black sand beaches, including a particularly well-known one in the town of Vík í Mýrdal. Here is a selection of photos of Iceland’s black sand beaches with large ice fragments and sand dunes,  set against the backdrop of glacial ice caps. Photos are courtesy of Neha Ganesh and Flickr users James West, Ade Russell and Oliver Rich. For more information about Iceland’s volcanoes and glaciers, look here and here.   Black Sand Beach, Iceland Image Courtesy: Neha Ganesh Black Sand Dunes, Iceland Image Courtesy: Neha Ganesh Black Sand Beach, Iceland Image Courtesy: Neha Ganesh Black Sand Beach in Vík í Mýrdal, Iceland Image Courtesy: Neha Ganesh   Photo Friday highlights photo essays and collections from areas with glaciers. If you have photos you’d like to share, let us know in the comments, by Twitter @glacierhub or email us at glacierhub@gmail.com.    Spread the...

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Mapping South Asia’s Glaciers

Posted by on Mar 5, 2015 in All Posts, Communities, Featured Posts, Images, Science | 0 comments

Mapping South Asia’s Glaciers

Spread the News:ShareRecent research has provided valuable information on glacier processes in the Hindu Kush Himalaya (HKH) mountains of South Asia, a region often called the “Third Pole” because it contains the largest area of ice outside the Arctic and Antarctic. Glacier retreat in this region has attracted considerable scientific and media attention. The 2007 Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) stated that Himalayan glaciers were shrinking faster than those in other parts of the world, and would likely be gone by the year 2035. This comment became controversial in 2009 because of its inaccuracy and weak basis in scientific research, and because glacier retreat in this region has major consequences for water supplies in one of the most densely-populated regions of the world. The IPCC made subsequent corrections in 2010. This video from 2010, ‘Himalayan Glaciers Melting Faster Than Anywhere Else in World,’ conveys the tone of concern during the period of the controversy.   Stemming from this controversy, documenting the glacier coverage in the HKH has become a topic of critical importance. A recent study by Bajracharya et al. (2015) helps establish the extent of glacier coverage in the HKH region and the rate of glacier change in several basins in this region. The rugged topography and the poor road networks in the HKH region have limited ground-based data collection. Remote sensing is therefore an attractive alternative. Bajracharya, a researcher at ICIMOD in Kathmandu, and his colleagues utilized satellite images, combining them in some cases with available ground-based data. The study maps glacial coverage and retreat for a period extending from about 1980 (the precise date varies from location to location) through 2010. They map the decadal glacial change for the 1980s, 1990s and 2000s  for four large representative basins which span the HKH region from west to east. The study basins are the Wakhan Corridor in Afghanistan, the Shyok Basin in Pakistan, the Imja Valley in Nepal, and the Lunana region in Bhutan. Glacier melt is a critical source of  drinking and irrigation water for large populations in the regiona and critical to hydropower generation as well; glacial processes are also important because of the associated risks of glacier lake outburst floods (recap Imja Lake in Nepal). So what can be learned from these newly assembled and analyzed data? First, the study reports, that despite the importance of glaciers in the HKH  region, they cover only 1.4% of the region. In addition, it finds that glacier retreat is proceeding at different rates in different places. The most rapidly retreating glaciers are the ones located below 5000 m above sea level and the ones that are smallest in area. Combining these factors, the most impacted basin in the study is the Wakhan Corridor in Afghanistan. The contributions of this study notwithstanding, scientific challenges in the HKH remain. The researchers note that there is continued uncertainty about glacier retreat and downstream impacts, because of uncertainties about future climate change and about the responses of glaciers to this change in this region, for which research remains incomplete.  This study sets the stage for future research, looking to past data and suggesting directions of future work. This prize-winning video from UNDP, the ‘Himalayan Meltdown,’ provides a thorough overview of the region and shows the need for ongoing research.         Spread the...

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