An Extended and Improved Special Sensor Microwave Imager (SSM/I) Period of Record

Hilawe Semunegus

NOAA/National Climatic Data Center, Asheville, North Carolina

Wesley Berg

Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado

John J. Bates and Kenneth R. Knapp

NOAA/National Climatic Data Center, Asheville, North Carolina

Christian Kummerow

Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado

ABSTRACT

The National Oceanic and Atmospheric Administration National Climatic Data Center has served as the archive of the Defense Meteorological Satellite Program Special Sensor Microwave Imager (SSM/I) data from the F-8, F-10, F-11, F-13, F-14, and F-15 platforms covering the period from July 1987 to the present. Passive microwave satellite measurements from SSM/I have been used to generate climate products in support of national and international programs. The SSM/I temperature data record (TDR) and sensor data record (SDR) datasets have been reprocessed and stored as network Common Data Form (netCDF) 3-hourly files. In addition to reformatting the data, a normalized anomaly (z score) for each footprint temperature value was calculated by subtracting each radiance value with the corresponding monthly 1° grid climatological mean and dividing it by the associated climatological standard deviation. Threshold checks were also used to detect radiance, temporal, and geolocation values that were outside the expected ranges. The application of z scores and threshold parameters in the form of embedded quality flags has improved the fidelity of the SSM/I TDR/SDR period of record for climatological applications. This effort has helped to preserve and increase the data maturity level of the longest satellite passive microwave period of record while completing a key first step before developing a homogenized and intercalibrated SSM/I climate data record in the near future.