An Assessment ofGOES-8Imager Data Quality

Abstract

The Geostationary Operational Environmental Satellite-8 (GOES-8), the first in the GOES I–M series of advanced meteorological satellites was launched in April 1994 and became operational at 75 °W longitude the following year. GOES-8 features numerous improvements over prior GOES platforms such as 1) improved resolution in the infrared (IR) and water vapor bands, 2) reduced instrument noise, 3) 10-bit visible and IR digitization, 4) greater image frequency, 5) more spectral bands, and 6) an independent sounder. A qualitative and quantitative comparison of the imager data from GOES-8 and GOES-7 shows that imagery from the newer spacecraft is superior in most respects. Improvements in resolution and instrument noise on GOES-8 provide sharper, cleaner images that allow easier detection of significant meteorological or oceanographic features. Infrared temperature comparisons between GOES-8 and GOES-7 were within 0.5°–2.0°C for all IR bands, indicating consistency between the two spacecraft. Visible band albedos from GOES-8 were at least 50% greater than GOES-7 for a wide range of scenes, suggesting that output from the GOES-7 visible detectors had degraded since its launch in 1987. Products derived from GOES-8 imager data for observing fog at night, fire detection, heavy precipitation estimation, and upper-level winds based on cloud or water vapor motion have been shown to be superior to similar products from GOES-7. Early difficulties with image registration and IR striping were alleviated after the first year. Based on the performance of GOES-8, future spacecraft in the GOES I–M series can be expected to provide many years of useful service to meteorologists, oceanographers, and the environmental monitoring community.