Ian Joughin serves as Deputy PI on the GSFC CryoDyn Earth Ventures 2 project. He is developing science and measurement objectives for the mission. He is also evaluating whether the mission and instrument are consistent with these objectives and provides expert advice to guide the mission planning and utilization of the data.
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Numerous recent studies have revealed rapid change in ice discharge from Greenland’s outlet glaciers. A near doubling in flow speed of many of Greenland’s glaciers substantially increased the rate at which the ice sheet calved icebergs to the ocean over the last five years.
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We are employing new remote sensing methods applied to multiple satellite data sets to measure the total discharge of ice from the grounded Antarctic Ice Sheet. This effort also will provide the most comprehensive mapping ever of the grounding line position, as well as ice thickness and velocity along and in the vicinity of the grounding line. These products are sensitive indicators of changes and will serve as benchmark data sets of the International Polar Year suitable for subsequent comparisons to identify and quantify future changes in the ice sheet.
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PI: Ian Joughin The West Antarctic Ice Sheet is losing mass, in large part because of rapid thinning of the Amundsen Coast glaciers. Estimates of Amundsen Coast thinning range from 46 to 86 Gtons/yr, with the 40-Gton/yr difference in estimates being nearly equivalent to the combined outflow of Mercer, Whillans, Kamb, and Bindschadler ice streams (46 Gtons/yr). While warmer ocean temperatures may drive this thinning, the large uncertainties in the current mass balance estimates largely arise from poor knowledge of the snowfall accumulation over Pine Island, Thwaites, Smith, Pope and Kohler glaciers. This International Polar Year project is determining accumulation rates in this vastly under-sampled region to remove the large uncertainties in current mass balance estimates.
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We are using field and remote sensing data to investigate Elevation Change Anomalies (ECAs) discovered recently in the Ross Sea sector of the West Antarctic Ice Sheet (WAIS), which reveal the filling and draining of subglacial lakes.
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Deeply embayed ice shelves and narrower fringing ice shelves surround much of Antarctica. Recent results indicate that these ice shelves help regulate the flow of upstream glaciers and ice streams (“ice-shelf buttressing”). This investigation focuses on determining the mass balance of Antarctica’s non-Peninsula ice shelves and on improving our knowledge of the processes that control basal melt.
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This investigation’s major goal is to develop and use models constrained by satellite and ground observations to study the controls on fast ice stream flow.
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IceBridge is a NASA project that supports the acquisition of various data from aircraft in both polar regions that will bridge the gap in coverage between the now defunct ICESat satellite and the next generation ICESat II to be launched in 2015 at the earliest. The main focuses of the data acquisition will be laser altimetry and radar measurements of ice sheets (Greenland and Antarctica) and sea ice (Arctic and Antarctica).
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