NSIDC science at AGU highlights sea ice, buried lakes in Greenland, and avalanche mapping | WPN World People News

Scientists from the National Snow and Ice Data Center (NSIDC) will present new research on Arctic sea ice extent predictions, buried lakes in Greenland, and avalanche mapping at next week’s American Geophysical Union (AGU) Fall Meeting in San Francisco, California.

A frozen meltwater lake is seen along the northeast Greenland coast from aboard the NASA P-3B aircraft on May 7, 2012.

NSIDC scientist Julienne Stroeve discusses developments in long-term and short-term sea ice extent predictions. Comparison between models participating in the World Climate Research Programme Coupled Model Intercomparison Project Phase 5 (CMIP5) and observations of sea ice extent and thickness show that historical trends from 85 percent of the model ensemble members remain smaller than observed, and spatial patterns of sea ice thickness are poorly represented in most models.

Part of the explanation lies with a failure of models to represent details of the mean atmospheric circulation pattern that governs the transport and spatial distribution of sea ice. These results raise concerns regarding the ability of CMIP5 models to realistically represent the processes driving the decline of Arctic sea ice and to project the timing of when a seasonally ice-free Arctic may be realized. On shorter time-scales, seasonal sea ice prediction has been challenged to predict the sea ice extent from Arctic conditions a few months to a year in advance.

NSIDC scientist Lora Koenig presents the discovery of buried lakes within the Greenland Ice Sheet. Radars flown by NASA’s Operation IceBridge detected the buried lakes around the margins of the ice sheet. Most of the buried lakes had no visible surface expression but the few buried lakes that were visible had a darker blue color where subsurface water was located.

The volume of retained water in the buried lakes is small compared to the total mass loss from the Greenland Ice Sheet, but the water will have important implications locally for the development of the englacial hydrologic network, ice temperature profiles, and glacial dynamics.

NSIDC research scientist Julienne Stroeve talks about the changing relationship between ice age and ice thickness in the Arctic. Researchers in the University of Colorado have been using ice age as a proxy for ice thickness in studying the Arctic’s declining sea ice. Along with a decline in extent, scientists have also seen a decline in thicker, older ice making the Arctic more vulnerable to higher temperatures. Stroeve and her colleagues compared ice age data from remote sensing satellites to several observational data sets on ice thickness. The comparisons reveal that while a near-linear relationship between age and thickness for ice up to 3 meters thick existed in earlier years, this relationship is changing.

NSIDC research scientist Jeff Deems presents initial results from mapping snow depth and snow depth change in avalanche starting zones at the Arapahoe Ski Basin Area in Colorado. Starting zones are near or at the top of an avalanche path, where unstable snow breaks loose from the snow-cover and starts to slide.

Varying distribution of snow depth in avalanche starting zones exerts a strong influence on avalanche potential and character. Extreme depth changes over short distances are common, especially in wind-affected, above-tree line environments. Snow depth also affects the ease of avalanche triggering. Deems tested high-resolution snow depth and depth change maps from a ground-based light detection and ranging (LiDAR) instrument to support active avalanche control and forecasting efforts.

Source: U.S. National Snow and Ice Data Center