Tuesday, 16 January 2007
GOES Infrared Sounders - the future perspective from the current applications
Exhibit Hall C (Henry B. Gonzalez Convention Center)
Since 1994 a new generation of Geostationary Operational Environmental Satellite (GOES) Sounders (from GOES-8 to GOES-13) has been measuring broad band radiances in 18 infrared (IR) spectral bands, ranging from approximately 3.7µm – 14.7 µm. These data have been used to provide atmospheric and cloud products for meteorological applications on an hourly basis over North America and adjacent oceanic regions. The products include clear-sky radiances, atmospheric temperature and moisture profiles, total precipitable water, cloud-top pressure, water-vapor tracked winds, etc. Products are generated operationally by NOAA/NESDIS in Washington, D.C. Some Sounder products, including total column ozone, are also produced at the Cooperative Institute for Meteorological Satellite Studies at the University of Wisconsin-Madison. Applications of those products include: nowcasting and forecasting of weather events, assimilation of cloud products into regional numerical forecast models, and monitoring of temperature and moisture changes in the pre-convective periods. The increased spectral, temporal and spatial resolutions of the Hyperspectral Environmental Suite (HES) on the GOES-R and beyond will provide a substantial increase in the quantity and quality of the products. The HES IR portion is hyperspectral sounder instrument suite with two threshold tasks. HES will provide high-spectral resolution Hemispheric Disk Soundings (DS) and Severe Weather Mesoscale (SW/M) soundings. HES DS provides better than 10 km spatial resolution from 3.7 µm to 15.4 µm with a one-hour refresh rate of the full disk, 62° local zenith angle. SW/M will cover a 1000 x 1000 km square in less than 5 minutes, at approximately 5 km spatial resolution for IR. The GOES-R HES will be a flexible instrument that can provide hourly coverage of the near full disk, or provide more frequent coverage of smaller areas. The latter will be used when there is the potential for explosive development of severe thunderstorms, hurricanes, or severe winter storms. It can also be used over areas where the numerical forecast models have low confidence (targeted observations). IR data from the HES will be used for: 1) providing an accurate, hourly three-dimensional picture of atmospheric temperature and water vapor: 2) tracking atmospheric motions by discriminating more levels of motion and assigning heights more accurately; 3) possibly distinguishing between ice and water cloud and identifying cloud microphysical properties; 4) providing a 5 km field of view (FOV) for better viewing between clouds and cloud edges; 5) providing accurate land and sea surface temperatures and IR surface emissivities; 6) distinguishing atmospheric constituents with improved certainty, including dust, volcanic ash and ozone; and 7) detecting clear-sky low-level atmospheric inversions. The HES-IR will be able to provide higher spectral resolution observations (on the order of 1 cm-1, compared to 20 cm-1 on today's broadband GOES sounder). Aspects of improvement of HES over current GOES Sounder includes: spatial coverage, vertical moisture information, nowcasting, numerical weather prediction, clouds, winds, dust/aerosols, trace gases, climate, ocean/land. With the improved spectral resolution, an improved surface emissivity can also be estimated. Current and future applications of GOES Sounder and HES are demonstrated and compared in this talk by using the current satellite and aircraft measurements as well as simulated data.