Posts by Christina Langone

Satellites Detect Both Steady and Accelerated Ice Loss

Posted by on May 24, 2016 in All Posts, Featured Posts, Science | 0 comments

Satellites Detect Both Steady and Accelerated Ice Loss

Spread the News:ShareA new study published in Geophysical Research Letters reports the findings of a pair of satellites that measure gravity to get a clearer picture of the continued ice mass loss in Greenland, the Gulf of Alaska, and the Canadian Arctic Archipelago. The study found accelerated ice loss in the Arctic, and steady loss in Alaska, which will have significant implications for sea level rise globally. The researchers, Christopher Harig and Frederik J. Simmons, both of Princeton University, analyzed data from the two satellites, called the Gravity Recovery and Climate Experiment (GRACE), in order to not only find the current state of ice mass within glaciers and ice sheets, but the changes in mass since 2003. GRACE’s dual satellites circle the Earth together, and minute fluctuations in their orbit serve as a basis for measuring the Earth’s gravitational field. The two are separated by approximately 137 miles, and as they fluctuate with the changing gravitational pull, the distance between the two varies slightly. (The two satellites are nicknamed Tom and Jerry, a reference to the cartoon cat and mouse.) Coupling the differing distances with precise GPS locations, GRACE is able to provide a view of the Earth’s gravity with “unprecedented accuracy” as NASA says. This level of detail allows researchers to easily find even minute trends in mass changes. GRACE is more commonly used over large areas, such as ice sheets, but in this research the authors studied areas “near the [lower] limit that can be resolved by GRACE data.” After thermal expansion, mountain glaciers and ice caps are the second highest contributor to sea level rise, making accurate and efficient study of the mass loss from smaller areas critical for future sea level projections. The researchers found that the glacial ice on the north region of the Gulf of Alaska was decreasing at a faster rate than the south region. GRACE detected an unexpectedly large ice loss in 2009 which the authors attribute to a lowered albedo after the eruption of Mount Redoubt. The Canadian Archipelago as a whole has been losing ice mass steadily. Within it, the Ellesmere Island region was stable in 2003, when the data was first collected, but mass loss has been accelerating since. In 2013, the researchers found that the mass loss within the Ellesmere Island region had dramatically accelerated, but has since continued closer to average. Baffin Island, the second area studied within the Archipelago, also saw significant ice loss but not at the same rate as Ellesmere. Greenland saw “an order of a magnitude” more total volume ice loss than Baffin and Ellesmere. Partially due to its sheer size, ice loss there is significant; in the previous decade the largest land-based contributor to sea level rise has been Greenland. As ice mass loss continues in these regions due to natural variability and climate change, it will be important to have accurate and localized data to better prepare for the corresponding sea level rise.   “Worldwide, on the order of 500 million people could be directly impacted by rising sea level by the end of this century. The human impact is combined with a large financial impact as well. So regardless of where people live, I think the impacts of ice loss and sea level rise will be easily seen in the future,” co-author Christopher Harig said in an email to GlacierHub. Spread the...

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Roundup: How Glaciers Affect and Are Affected By Water

Posted by on May 23, 2016 in All Posts, Featured Posts, Roundup | 0 comments

Roundup: How Glaciers Affect and Are Affected By Water

Spread the News:ShareEach week, we highlight three stories from the forefront of glacier news. Totten Glacier Hurtles Towards Retreat and Possible Collapse From Nature: “Satellite-based observations indicate that the margin of Totten Glacier may be experiencing greater ice loss than anywhere else in East Antarctica. This, coupled with the presence of low-lying subglacial basins upstream means the Totten Glacier catchment area could be at risk of substantial ice loss under ocean-warming conditions.” Learn more about the processes causing this retreat and the potential sea level rise associated with it.   Are Dams the Glaciers of Tomorrow? From Swiss Federal Institute for Forest, Snow and Landscape Research WSL: “Water management in reservoirs could substantially mitigate future summer water shortages, expected as a consequence of ongoing glacier retreat, researchers report. The team simulated the effect of climatic change on glaciers across the European Alps and estimated that two thirds of the effect on seasonal water availability could be avoided when storing water in areas becoming ice free.” Find out how these researchers suggest dealing with glacier retreat and water supplies. Scientists Present New Research on Tibet’s Climate Risks From The Columbus Dispatch: “A consortium of scientists from around the world have gathered in Columbus at Ohio State University’s Byrd Polar and Climate Research Center for the first U.S. meeting about climate issues facing the Tibetan Plateau, a region that includes about 100,000 square kilometers of glaciers that provide drinking water to nearly a third of the Earth’s people.” Read more about the importance of the Tibetan Plateau and why these scientists feel action is so urgently needed. Spread the...

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Photo Friday: Jostedalsbreen Glacier

Posted by on May 6, 2016 in All Posts, Featured Posts, Images, Uncategorized | 0 comments

Photo Friday: Jostedalsbreen Glacier

Spread the News:ShareJostedalsbreen Glacier, the largest glacier in northern Europe, is located within Jostedalsbreen National Park which was founded in 1991 in Norway. The Jostedalsbreen Glacier is so large that it alone covers over a third of the park and separates two of the longest fjords in the world. It is fitting that Norway has such an imposing glacier since the most iconic Norwegian characteristics—fjords and valleys—owe their creation to past glacial movements. Scientists have flocked to this glacier for centuries to study its retreat since the Little Ice Age, particularly with an interest in studying post-glacial vegetation and landscape. As climate change accelerates glacial retreat across the world, a degree of urgency is added to the quest to learn from Jostedalsbreen Glacier’s retreat. Sometimes, the past can help us prepare for the future.   - MattW -/Flickr Karen Blaha/Flickr Karen Blaha/Flickr Guttorm Flatabø/Flickr Roman Königshofer/Flickr Spread the...

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Slower Evaporation Rate Spurs Tibetan Lake Growth

Posted by on May 4, 2016 in All Posts, Featured Posts, Science, Uncategorized | 0 comments

Slower Evaporation Rate Spurs Tibetan Lake Growth

Spread the News:ShareA new study in the Journal of Hydrology uses a novel modelling technique that helps scientists understand the effect of evaporation on the expansion of lakes in the inner Tibetan Plateau. This research also has implications for the use of climate models on the Plateau. In addition, the work has broader significance for weather patterns beyond Tibet, due to the plateau’s influence on the atmospheric circulation of the Asian Monsoon system. The researchers focused on Nam Co Lake, the second largest of the more than one thousand lakes on the Tibetan Plateau. Unlike many lakes, which drain through rivers, this lake is in a closed basin, losing water only through evaporation. There is no bigger lake at a higher altitude than this body of water anywhere in the world. In fact, Nam Co Lake is expanding, and the researchers wanted to better understand why. Seeking a fresh approach, the researchers aimed to specify the role of evaporation in this expansion. Led by Ning Ma of the Institute of Tibetan Plateau Research, Chinese Academy of Sciences, they found that the expansion of Nam Co Lake is partly caused by decreased rates of evaporation, possibly due to declining wind speeds and decreased solar radiation. There have been many studies exploring the rapid expansion of lakes in the region since the 1990’s, but there is no agreement on the explanation for this phenomenon. Past studies have looked at increased glacial runoff or increased precipitation as the main drivers. But the authors of this study explain that to fully understand the expansion of this closed lake, evaporation, a factor often neglected by researchers, needs to be incorporated as well.  The authors indicate that evaporation in this lake, as in other lakes, depends on several factors: the radiation that reaches the lake’s surface, air temperature, wind speed, and the dryness of the air. In order to find which of these variables has the largest effect, the scientists correlated the average values of each with the evaporation rates over the lake. Wind speed, they concluded, was most plausible candidate. However, the lack of nearby weather stations and the mountainous landscape of the region pose an issue for the construction of accurate models which include wind speed. Because of this, the researchers used a different model than is usually employed during evaporation studies; this alternate method is called a complementary relationship lake evaporation (CRLE) model. The CRLE model did not include wind speed measurements, but the researchers can estimate this factor by including an air stability factor that includes variables for heat and moisture content. The study suggests that the ability to more accurately model the rates of evaporation without wind speed data is the key to counterbalancing the lack of meteorological observations in this area. Further, the need to examine the lake over decades can best be addressed by models, granted the lack of data from the weather stations in the region. Accurate models may be able to help those in the region better understand lake expansion. The Tibetan Plateau is of great regional importance because of the role it plays in the Asian Monsoon system. Simply put, the heat energy (which is affected by evaporation) from the plateau thermally regulates the monsoon circulation patterns. Changes in evaporation rates from lakes may have implications for the many areas affected by the Asian Monsoon. By providing an assessment of the CRLE model, which the authors argue provides a more accurate representation of evaporation, this study may aid in the understanding of the processes taking place in this critical, but rapidly changing, region.   Spread the...

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Rocks and Rain Fix Nitrogen in Post-Glacial Sites

Posted by on Apr 19, 2016 in All Posts, Featured Posts, Science | 0 comments

Rocks and Rain Fix Nitrogen in Post-Glacial Sites

Spread the News:ShareA new study in Plant and Soil found that the input of nitrogen from the atmosphere, via a process of rain funneling through rocks, created levels of nitrogen that are adequate to support plant growth in post-glacial alpine soil, challenging the common view that the element is the primary limiting factor in deglaciated areas. In fact, the researchers found that phosphorous, due to the low-weathering rates and high nitrogen deposition of the region, is the element in soil which limits post-glacial plant life colonization. The team was lead by Hans Göransson of the University of Natural Resources and Life Sciences, Vienna. The finding challenges the widely-held view that the only plants capable of colonizing post-glacial environments are species that are able to fix nitrogen from the atmosphere. Instead, as this work shows, natural processes enable other plants to become colonizers in the European Alps. This research may have implications for future ecosystem plant colonization and biodiversity, a topic of interest to scientists as glaciers retreat and expose new soils in many regions of the world. The team, focusing on Damma Glacier in Switzerland, found that the expected nitrogen-fixing plants were usually absent in the early stages of these post-glacial sites, contradicting what previous research has suggested. The study’s findings differ from the research done in recently deglaciated areas in Glacier Bay in Alaska and on the Franz Josef glacier in New Zealand, which show an abundance of nitrogen-fixing plants in post-glacial sites. Most plants are unable to process atmospheric nitrogen directly and can only absorb it once it undergoes a transformation within the soil. (Nitrogen is essential for plant growth.) Some plants, however, undergo a process called nitrogen fixation which converts atmospheric nitrogen into a form useful for them. Bacteria in the plant’s roots help, as they are able to convert the nitrogen into a usable form. Because of this capacity, nitrogen-fixing plants are generally thought of as the colonizing species in post-glacial sites, since these rocky areas are typically so low in soil nitrogen that plants that cannot fix nitrogen would not be able to grow. Once the nitrogen-fixing plants begin to die and the nutrients from them return to the soil, a more diverse second generation of plants can grow. The team set out to explore how plants in the region were colonizing even when nitrogen-fixing plants were not present. They found that nitrogen from the atmosphere was deposited into the soil by newly exposed rocks, which acted as funnels when it rained. This process provided sufficient amounts of nitrogen for plant growth, and thus allowed non-nitrogen fixing plants to grow in these areas. The researchers divided the Damma post-glacial area into a total of 21 sites across three time periods related to the age of the soil since the glacier retreated: pioneer (fewer than 16 years since deglaciation), intermediate (57-80 years), and late-stage (108-137 years). The Damma glacier has had a long and well-tracked retreat, making the separation of time periods easy. The team used ion exchange resin bags at each site that measure the amount of nitrogen in the soil. They also took the above-soil measurements by collecting the biomass growing at the sites and analyzing the nitrogen levels. They found that nitrogen levels were high in the pioneer stage, followed by low levels in the intermediate, and high levels again in the late stage. As the nitrogen channels through rocks and into the soil, it creates an overabundance of nitrogen at first, since there is little or noplant life to use the element. This process eventually creates hotspots of plant growth, but as...

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