Construction of a Consistent Microwave Sensor Temperature Record in the Lower Stratosphere Using Global Positioning System Radio Occultation Data and Microwave Sounding Measurements

In this study, we use FORMOSAT-3/Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) Global Positioning System (GPS) radio occultation (RO) data and CHAllenging Minisatellite Payload (CHAMP) data to simulate Advanced Microwave Sounding Unit (AMSU) brightness temperatures for the lower stratosphere (TLS) and compare them to AMSU TLS from different National Oceanic and Atmospheric Administration (NOAA) missions from January 2002 to Dec. 2008. Our analysis shows that because RO data do not contain mission-dependent biases and orbit drift errors, and are not affected by on-orbit heating and cooling of the satellite component, they are very useful to identify the AMSU time/location dependent biases for different NOAA missions. Using RO simulated AMSU Tbs, we calibrate AMSU TLS from different NOAA missions in the same month. A new microwave sensor temperature record in the lower stratosphere from 2002 to 2008 is constructed. The derived TLS record is compared with the newly available TLS datasets provided by Remote Sensing Systems (RSS) and University of Alabama in Huntsville (UAH). The causes of the TLS differences among these datasets are discussed.