POLAR PATHFINDER DATA SETS
There are three major NASA/NOAA Pathfinder data sets with significant relevance to the polar regions:
1. Advanced Very-High-Resolution Radiometer (AVHRR) Global Area Coverage, which measures global vegetation, radiance, sea-surface temperature, and clouds and aerosol data;
2. Television Infrared Observing Satellite Operational Vertical Sounder, which produces level-3 (gridded to 100 km boxes), daily-averaged atmospheric data, such as temperature and moisture profiles, surface skin temperature, cloud fraction and height, bulk boundary layer parameters, and surface pressure;
3. Special Sensor Microwave/Imager, which produces hydrology, ocean, snow, and ice data.
Other Pathfinder activities are the joint NASA/USGS/EPA LANDSAT Pathfinder, which includes land-cover data, and the NASA Scanning Multispectral Microwave Radiometer (SMMR). Each Pathfinder activity had a designated science working group responsible for identifying needed products, algorithms, and user services. Research teams coordinate all data sets based on a common map projection and use consistent file-naming conventions and validation methods.
have important significance for climate research in the polar region (Box 1-1).
Pathfinder data sets and derived products are made available to researchers through the Distributed Active Archive Centers (DAACs). The National Snow and Ice Data Center (NSIDC), a component of the DAACs, distributes the polar Pathfinder data sets to the scientific community as part of its many responsibilities related to cryospheric research. In parallel to the polar Pathfinder program, a related group of data sets is being developed through the Polar Exchange at the Sea Surface (POLES) and RADARSAT Geophysical Processing System (RGPS) projects.1
1 The POLES project is an interdisciplinary effort to look at the polar processes that influence the global heat and hydrological cycles; it combines satellite and in situ data in collaboration with the polar Pathfinder Program to create a complementary data set to explore complex physical processes in the polar regions. The RGPS polar products measure geophysical quantities such as sea-ice motion and the thickness distribution of thin ice using Synthetic Aperture Radar archived at the Alaska SAR Facility.