VAS
type: Concept
in scheme: instruments
definition: The VAS is an advanced version of the Visible Infrared Spin Scan Radiometer (VISSR) flown on the SMS and early GOES satellites. This instrument flown on GOES 4-8 is a visible and infrared radiometer that provides image (VISSR mode) and sounding (VAS mode) data. The VAS retained the VISSR dual-band imaging function while expanding to 6 infrared channels. The additional spectral bands provided are sensitive to the effects of atmospheric constituents which allows for determination of surface and cloud-top temperatures as in VISSR along with three-dimensional structure of the atmospheric temperature and water-vapor distribution. The 12 Infrared spectral bands span central wavelengths from 3.9 to 15.0um. The ground resolution is 1km in the visible range and 7km (imaging) and 14km (sounding) in the infrared ranges. The swath width is the Earth disc. The following is a table displaying the Infrared spectral bands. SPECTRAL PRESSURE LEVEL WAVELENGTH BAND (mb)* (um) BAND -------- -------------- ---------- ------------- 1 65 14.730 CO2 2 100 14.480 CO2 3 325 14.250 CO2 4 450 14.010 CO2 5 SURFACE 13.330 CO2 6 700 4.525 CO2 7 SURFACE 12.660 H2O 8 SURFACE 11.170 WINDOW 9 375 7.261 H2O 10 330 6.725 H2O 11 280 4.444 CO2 12 SURFACE 3.945 WINDOW * Level of maximum weighting function for the spectral band. CO2 is Carbon Dioxide. H2O is Water Vapor. Investigators: Dr. Verner E. Suomi, University of Wisconsin-Madison Mr. William E. Shenk, NASA Goddard Space Flight Center Entry taken from: Colwell, R.N. (Editor-in-Chief), Manual of Remote Sensing: Second Edition, Volumes I and II, American Society of Photogrammetry, 1983. Cornillon, P., A Guide to Environmental Satellite Data, University of Rhode Island Marine Technical Report 79, 1982. Rao, P.K., S.J. Holmes, R.K. Anderson, J.S. Winston, and P.E. Lehr, Weather Satellites: Systems, Data, and Environmental Applications, American Meteorological Society, Boston, 1990. ISBN 0-933876-66-1 Group: Instrument_Details Entry_ID: VAS Group: Instru…

Profilers/Sounders
type: Concept