Quality control of SSM/I data using climatological statistics

The National Oceanic and Atmospheric Administration's National Climatic Data Center serves 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 present. Passive microwave satellite measurements from SSM/I are used to generate climate products in support of national and international programs. The SSM/I Temperature Data Record (TDR) and Sensor Data Record (SDR) data sets are reprocessed and stored as network Common Data Form (netCDF) three-hourly files. In addition to reformatting the data, a normalized anomaly (z-score) for each footprint temperature value is calculated by subtracting each radiance value with the corresponding monthly one degree grid climatological mean and dividing it by the associated climatological standard deviation. Threshold checks are also used to detect radiance, temporal and geolocation values that are outside expected ranges. The application of z-scores and threshold parameters in the form of embedded quality flags improves the fidelity of the SSM/I TDR/SDR period of record for climatological applications. This effort preserves and increases the data maturity level of the longest satellite passive microwave period of record, by completing a key first step prior to developing a homogenized and inter-calibrated SSM/I Climate Data Record.