Greenland: Reanalysis of the Energy Budget of the Ice Sheet (GREBIS)
Atmospheric reanalyses have proven to be useful tools for synthesizing diverse and irregularly spaced atmospheric observations into internally consistent gridded data sets. Global reanalyses, as prepared by NCEP and ECMWF, provide complete global coverage, but are limited by relatively coarse resolution and by models which may not capture all of the important physical processes acting in a particular region. We propose to conduct a short-duration reanalysis (5 years) of the atmospheric and surface state of the Greenland ice sheet using a high resolution limited area atmospheric model adapted to the polar regions. This reanalysis will be conducted using a horizontal resolution (20 km) that is one order of magnitude greater than global reanalyses and will utilize polar specific observational datasets including the PARCA Greenland Climate Network (GC-Net) automatic weather station (AWS) array and NOAA/NASA Polar Pathfinder satellite derived products. The quality of the reanalysis will be evaluated using unassimilated observational data such as satellite derived cloud cover, radiative fluxes, and snow melt.
The gridded Greenland atmospheric reanalysis will serve as a high resolution atmospheric data set for additional studies of the Greenland ice sheet / atmosphere system. The specific objectives of this research are to:
- Develop a regional reanalysis system optimized for use over the Greenland ice sheet, based on the Polar MM5
- Create a 5-year reanalysis of the atmospheric state over the Greenland ice sheet
- Estimate the magnitude of errors in the regional reanalysis data set, specifically focusing on issues related to energy and water conservation
- Compare the quality of the regional reanalysis to global reanalyses
- Evaluate the mass balance of the Greenland ice sheet using the new regional reanalysis data set, and compare this with other estimates of the ice sheet mass balance