The Arctic, which was once often excluded from global displays of geophysical fields, has moved to the forefront of climate research. Global climate models (GCMs) have long predicted that the high latitudes would be the bellwether of the climates response to anthropogenic modifications because of strong feedback mechanisms involving snow, sea ice, clouds, and radiation. Many questions and uncertainties surround parameterizations of polar processes in GCMs, however, and tremendous differences exist between model simulations for present-day climate conditions [e.g., Gates et al., 1999],to say nothing of future climate predictions.
In recognition of these issues and the potential contribution that satellite data could make to addressing them, NASA and the National Oceanic and Atmospheric Administration (NOAA) initiated the Pathfinder program (see Web site: http://xtreme.gsfc.nasa.gov/pathfinder/). The TIROS Operational Vertical Sounder (TOVS) Polar Pathfinder data set, produced with funding from this program, provides a new source of information about the Arctic surface and atmosphere that may offer insight into the complex processes that control the Arctic climate system.