- NASA has announced the selection of 33 scientific investigations which have been funded to study the polar regions of Earth as part of the objectives of the International Polar Year (IPY). Three of these scientific investigations will utilized Landsat data. Landsat will help researches look at glacier distribution in part of the Asian Arctic Basin, measure the ice discharge of Antarctica’s terrestrial ice sheet, and map tree abundance in forest-tundra transition zones.
- Vladimir Aizen/University of Idaho
Estimation of seasonal snow cover, glacial and lake area changes at the Ob/Yenisey river heads during the last 40 years using NASA ESE products and in situ data
The Altai-Sayan mountains geographically define the southern periphery of the Asian Arctic Basin. The Ob and Yenisey rivers are the only Siberian rivers that are fed by fresh water from the Altai-Sayan alpine glaciers. The water flowing from the Ob and Yenisey rivers accounts for 40% of the total river inflow into the Arctic Ocean. The 2,340 Altai-Sayan’s glaciers have been receding from the middle of 19th century, but there has been no precise estimation of the change in glacial areal extent and seasonal snow-cover and the consequent changes in water resources.
Our main objective is to estimate changes in snow- glacial- and lake-covered areas, and glacier volume, at the head of Ob/Yenisey river basins over forty years, and also to simulate and forecast snow and glacial runoff variability.
Research approaches: (1) Collect and process in-situ data and NASA data products; (2) Simulate the snow, glacier, and lake area and volume changes through model development; (3) Implement snow/glacial runoff model parameters; (4) Characterize the annual to decadal variations in river runoff and assess the climate-driven impact on future snow/glacial water resources.
Methods (1) We will check data for homogeneity and representativeness. Topographic and photogrammetric measurements will be georeferenced to a common coordinate system; (2) Glacial area distribution will be evaluated by Landsat and Terra ASTER data; high-resolution satellite products (IKONOS and CORONA) will be used for validation. Sub-pixel analysis techniques using MODIS and AVHRR data will be used for snow mapping, and snow-covered area will be validated using Landsat and ASTER image data. Aerial photographs and Corona photographs and ASTER, SPOT and IKONOS images will be used for subsequent lake area changes. (3) A snow/glacier melt Runoff Model will simulate the annual mean runoff through snow distribution, snow/glacier ablation and quantifying the precipitation partitioning; the snow/glacier melt runoff models will be assimilated with MODIS Evapotranspiration products, MODIS Snow Cover, and MODIS Land Cover Science Data Product (MOD12Q1). (4) Forecast of glacier retreat will be based on the Equilibrium Line Altitude, which is determined through mean summer air temperatures and annual precipitation. Hypothetical climate-change scenarios will be imposed as an annual progression of changes in temperature and precipitation.
The proposed project addresses an important unifying component of the NASA IPY Program, particularly with respect to the terrestrial components of the cryosphere in the Cold Land Regions of the Northern Hemisphere. Modeling and predicting glacier and snow cover changes is an important unifying component of the U.S. Global Change Research Program and the World Climate Research Program, and will contribute to the International Climate and Cryosphere Program, the Climate Variability and Predictability Research, and the North Eurasia Earth Science Partnership Initiative.
Robert Bindschadler/ NASA Goddard Space Flight Center
Total Antarctic Ice Sheet Discharge: An IPY Benchmark Data Set
We propose to employ new remote sensing methods applied to multiple satellite data sets (ICESat, Landsat, and InSAR) to complete the first-ever measurement of the total discharge of ice from the grounded Antarctic Ice Sheet. This will significantly reduce the uncertainty in this fundamental characteristic of the ice sheet that heretofore has been based only on the outflow of major outlets. This work will also provide the most detailed and 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. An international team of student analysts and professional mentors will use standardized methods to accomplish these objectives. Field validation will be provided to quantify the accuracy of the results. Data products will be made publicly available through the Antarctic data portal hosted at the USGS EROS Data Center and the National Snow and Ice Data Center.
Jon Ranson/NASA’s GSFC
Assessing Forest-Tundra Transition Zone In the Arctic With Multi-Sensor Satellite Data
In response to NASA International Polar Year Solicitation for “integrated analysis of multiple satellite data sets, … in polar regions addressing the scientific questions defined by NASA in its Earth Science Enterprise Strategy”, the proposed study will map and characterize the current forest-tundra transition zone, and reveal its changes during the last several decades with multi-sensor satellite data and field observations for portions of the circumpolar ecotone.
Monitoring the dynamics of the circumpolar boreal forest and Arctic tundra boundary is important for understanding the causes and consequences of changes observed in these areas. This ecotone, the world’s largest, stretches for over 13,400 km and marks the transition between the northern limits of forests and the southern margin of the tundra. Because of the inaccessibility and large extent of this zone, remote sensing data can play an important role for mapping the characteristics and monitoring the dynamics. Current land cover maps produced from AVHRR, VEGETATION, and MODIS data are not consistent along this forest-tundra transition zone, and do not provide enough detailed information on vegetation structure changes across the transition zone. Our previous studies in Ary-mas, Siberia showed that the taiga-tundra transitional area can be characterized using multi-spectral Landsat ETM+ images, multi-angle MISR red band reflectance images, RADARSAT images with larger incidence angle, or multi-temporal and multi-spectral MODIS data. Because of different resolutions and spectral regions covered, the transition zone maps derived from different data types were not identical, but the general patterns were consistent.
In this study we will incorporate the 3rd dimension in the characterization for the tundra-forest ecotone using existing lidar measurements and develop a benchmark for the midpoint of the ecotone along a substantial portion of the ecotone. We will use of multi-sensor data fusion to identify the existing forest-tundra ecotone, characterize the spatial patterns of forest-tundra mosaic, and investigate its changes. The specific objectives and tasks in the proposed study include:
1. Map tree abundance and land cover types using high resolution data in intensive study sites along the forest-tundra transition zone and characterize the spatial patterns of tree-tundra mosaic across the boundaries. These data include Landsat-7, ASTER, radar (ERS, JERS-1, RADARSAT, ENVISAT ASAR) and ALOS PALSAR and Panchromatic Remote Sensing Instrument for Stereo Mapping (PRISM).
2. Investigate the potential of GLAS waveform data and MISR data for characterization of vegetation structure across the forest-tundra transition zone.
3. Produce benchmark maps at 500m pixel size for forest-tundra transition zone by validating and improving the continuous tree cover maps and MODIS 1-km classification map from MODIS 250m or 500m data using training data generated in tasks 1 and 2, and
4. Quantify the changes of tree density and advance of “tree line” in intensive study sites using historical satellite data and field observations.
This study will result in a benchmark map of the circumpolar Arctic forest-tundra transition zone, and verified methods for periodic mapping of this ecotone using multi-sensor satellite data.
+ NASA press release