McIDAS (Man - Computer Interactive Data Access System) receives digital satellite imagery from the Geostationary Meteorological Satellite (GMS), the National Oceanic and Atmospheric Administration's (NOAA) Polar Orbiting Earth Satellites (POES), and the Defense Meteorological Satellite Program (DMSP) satellites. The imagery can be displayed, animated, color enhanced for detail,and overlaid with surface and upper - air meteorological information.
The GMS provides hourly infrared (IR), water vapor, and visible images of much of the Pacific Ocean region west of Hawaii. The resolution is approximately 1.25 km in the visible and 5 km in the IR and water vapor channels.
POES imagery is available approximately every six hours via two orbiting satellites tracked by the DMSP antenna. Data are received from two on - board sensors, the Advanced Very High Resolution Radiometer (AVHRR), and the Television Infrared Observation Satellite (TIROS) Operational Vertical Sounder (TOVS). The five channel AVHRR provides 1 km visible, near IR, IR, and water vapor window imagery. The TOVS complex includes a High - resolution Infrared Radiation Sounder (HIRS). Among the 20 HIRS channels are bands sensitive to carbon dioxide and water vapor absorption. A cloud height and detection algorithim for locating high - level cirrus clouds uses these channels. This state-of-the-art carbon dioxide radiance rationing technique overcomes some weaknesses inherent in the IR blackbody temperature used to estimate the altitude of cirrus. Cloud emissivity, total ozone estimates, and temperature profiles are also extracted from the TOVS data.
McIDAS can receive Geostationary Operational Environmental Satellite (GOES) data relayed from similar systems located at Vandenburg Air Force Base and the Space Science and Engineering Center (SSEC), University of Wisconsin. This capability provides access to satellite coverage reaching from the continental United States to the western Pacific. McIDAS also displays data collected from local and remote rawinsonde sites, pilot reports, surface hourly aviation and synoptic reports from land stations and ships, and National Meteorological Center analysis and forecast products.
DMSP data are available at approximately six hour intervals from two polar orbiting satellites. Orbital Line Scan (OLS) data includes visible wavelength imagery at resolutions of 0.33 and 3.7 km and IR wavelength imagery at 0.4 and 4.5 km resolutions. Data from the Special Sensor Microwave Imager (SSMI) are commonly used to derive surface wind speed, sea state, and rainfall rate. Various processing techniques within McIDAS allow the images to be enhanced at various temperature ranges to emphasize the cloud cover at selected altitude levels.
