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WindSat
STATUS
Current
AVAILABILITY
Sea Surface Temperature Ocean Surface Wind Vector Columnar Precipitable Water Vapor Columnar Cloud Liquid Water Sea Ice Retrievals Soil Moisture Brightness Temperatures
REQUEST PROCEDURE
Researchers can gain access to the WindSat data by contacting windsatdata@nrl.navy.mil or visiting http://www.cpi.com/datacenter
Satellite Instruments
WindSat is a satellite-based polarimetric microwave radiometer developed by the Naval Research Laboratory Remote Sensing Division and the Naval Center for Space Technology for the U.S. Navy and the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Integrated Program Office (IPO). WindSat is designed to demonstrate the capability of polarimetric microwave radiometry to measure the ocean surface wind vector from space. It is the primary payload on the Coriolis mission, which is jointly sponsored by the DoD Space Test Program and the U.S. Navy (SPAWAR PMW-180). Spectrum-Astro of Gilbert, Arizona, built the spacecraft. The WindSat/Coriolis mission was launched on a Titan II rocket from Vandenburg Air Force Base on 06 January 2003. In addition to providing the Navy with badly needed ocean surface wind vector measurements, WindSat also measures other environmental parameters such as sea surface temperature, total precipitable water, integrated cloud liquid water, and rain rate over the ocean. Furthermore, WindSat provides risk reduction for the NPOESS Conically-scanned Microwave Imager and Sounder (CMIS), which is the future operational microwave imager tasked with supplying ocean surface wind data. Risk reduction activities include supplying data for model and retrieval algorithm development; sharing technical lessons learned; and using WindSat data to develop CMIS calibration, data exploitation, and data assimilation applications. The WindSat radiometer operates in discrete bands at 6.8, 10.7, 18.7, 23.8, and 37.0 GHz. Table 1 provides key design and performance parameters of the system. The 10.7, 18.7, and 37.0 GHz channels are fully polarimetric. The 6.8 channel is dual-polarization (vertical and horizontal), and is more sensitive to sea surface temperature (SST) than to winds. Thus it is used to remove environmental noise due to variations in SST. Similarly, the 23.8 channel has dual-polarization and is highly sensitive to atmospheric water vapor. Thus, measurements at 23.8 GHz enable algorithms to correct for the effects of atmospheric attenuation on signals from the ocean surface. WindSat uses a 1.8-m offset reflector antenna fed by 11 dual-polarized feed horns. The antenna beams view the Earth at incidence angles ranging from 50 to 55°. Table 1 shows the nominal beamwidth and resulting surface spatial resolution of each band. The Coriolis satellite orbits Earth at an altitude of 840 km in a Sun-synchronous orbit. The satellite completes just over 14 orbits per day. The orbit and antenna geometry result in a forward-looking swath of approximately 1000 km and an aft-looking swath of about 350 km. The fully integrated WindSat payload stands 10 ft tall and weighs approximately 675 lbs.
CONTACT
William Johnston
Naval Research Laboratory (NRL)
4555 Overlook Avenue, S.W. Washington, D.C. 20375
william.johnston@nrl.navy.mil
SPECIFICATIONS
Measurment TypeMicrowave-imager
Platform TypeWindsat
OrbitSun synchronous
Spectral Coverage
Active/PassivePassive
Scan PatternConical
Variables
Altitude830
Inclination
Repeat Time
Wavelength6.8 to 37GHz
Number of Bands5
Start DateFeb 2003
Temporal Coverage
Swath Width
REFERENCES
http://www.nrl.navy.mil/WindSat/ http://www.nrl.navy.mil/WindSat/Description.php
UPDATED ON
21 Sep 2009 08:41