Assessments of F16 Special Sensor Microwave Imager and Sounder Antenna Temperatures at Lower Atmospheric Sounding Channels

Banghua Yan,Fuzhong Weng

doi:10.1155/2009/420985

Abstract

The main reflector of the Special Sensor Microwave Imager/Sounder (SSMIS) aboard the Defense Meteorological Satellite Program (DMSP) F-16 satellite emits variable radiation, and the SSMIS warm calibration load is intruded by direct and indirect solar radiation. These contamination sources produce antenna brightness temperature anomalies of around 2 K at SSMIS sounding channels which are obviously inappropriate for assimilation into numerical weather prediction models and remote sensing retrievals of atmospheric and surface parameters. In this study, antenna brightness temperature anomalies at several lower atmospheric sounding (LAS) channels are assessed, and the algorithm is developed for corrections of these antenna temperature anomalies. When compared against radiative transfer model simulations and simultaneous observations from AMSU-A aboard NOAA-16, the SSMIS antenna temperatures at 52.8, 53.6, 54.4, 55.5, 57.3, and 59.4 GHz after the anomaly correction exhibit small residual errors (<0.5 K). After such SSMIS antenna temperatures are applied to the National Center for Environmental Prediction Numerical Weather Prediction (NWP) model, more satellite data is used and the analysis field of the geopotential height is significantly improved throughout troposphere and lower stratosphere. Therefore, the SSMIS antenna temperatures after the anomaly correction have demonstrated their potentials in NWP models.

Highlights

On October 18, 2003, the F16 satellite was successfully launched and carried the first Special Sensor Microwave Imager/Sounder (SSMIS)
Soon after launch of the SSMIS, some anomalies were discovered in the temperature data record (TDR) data for sounding channels primarily due to (a) thermal emission by the main reflector and (b) unaccounted solar radiation impinging
These results indicate that while the magnitude of each anomaly is variable with channel, the phase of each channel anomaly is similar because their time difference is small

Summary

Introduction

On October 18, 2003, the F16 satellite was successfully launched and carried the first Special Sensor Microwave Imager/Sounder (SSMIS). The SSMIS instrument has twenty four channels to measure the Earth’s radiation at frequencies between 19 and 183 GHz [1]. It is the first operational microwave satellite radiometer for profiling temperature and humidity using a conical scanning mode so that the viewing area and slant path remain nearly constant as it scans the earth. The accuracy of SSMIS-derived surface and atmospheric products is critically dependent on the accuracy of the brightness temperature measurements. National Oceanic and Atmospheric Administration (NOAA) receives the F16 SSMIS data in both antenna brightness temperature data record (TDR) and sensor brightness temperature data record (SDR) formats through a data sharing agreement with the Defense Meteorological Satellite Program (DMSP). Soon after launch of the SSMIS, some anomalies were discovered in the TDR data for sounding channels primarily due to (a) thermal emission by the main reflector and (b) unaccounted solar radiation impinging

Methods

Findings

Discussion

Conclusion