Retrieval Simulation Studies From Advanced Operational Polar Orbiting High Resolution Infrared and Microwave Sounders

In the 2008 timeframe the United States will launch the first in a series of National Polar Orbiting Environmental Satellite System (NPOESS) spacecraft carrying several new meteorological sensors designed to provide improved measurements for military and civilian weather forecasting. One of these sensors is the Cross-track Infrared Sounder (CrIS) which, along with a co-registered cross-track microwave sounder, combine to form a suite capable of taking the high spatial and spectral resolution radiometric measurements required to produce global vertical temperature and humidity profiles under all atmospheric conditions. The CrIS, a Michelson Interferometer covering the spectral region of 4 to 15 microns in 3 bands has a spatial resolution of 10km arranged in a 3 by 3 pattern of GIFOVs, and its high spectral resolution produces about 1200 spectral channels. Microwave sounding will be provided by either the existing cross-track microwave temperature and moisture sounders (AMSU-A/MHS), or an Advanced Technology Microwave (ATMS) sounder being developed by NASA. The retrieval, forward model, and cloud clearing algorithms to be utilized are based on AIRS, TOVS and HIS heritage. The operational system is required to produce profiles in the troposphere with errors less than 1.0K rms and 15% rms for temperature and water vapor respectively.

As part of the Phase I Risk Reduction effort, Raytheon has developed a Testbed that simulates the retrieval of temperature and humidity vertical profiles based upon these components, and includes the effects of stressed and anomalous operating conditions. This paper will highlight the results of simulations performed using this Testbed for the evaluation of various algorithm and sensor designs. In addition, the effects of retrieval and cloud clearing algorithm upgrades and adjustments will also be highlighted.