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Microwave Sensors
Microwaves can tell us much that conventional (visual and infrared) satellite data cannot. They can give meteorologists information about surface winds over broad areas of the oceans, cloud water content, rain rate, water vapor content, and land surface temperature. In addition, they can give information on ice concentration and age, especially valuable to Navy support. Forecasters supporting Army operations can get data on soil moisture, land surface characteristics, and vegetation type. |
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Special Sensor Microwave Imager (SSM/I) Spectral Coverage: Seven Channels in the 19, 22, 37, and 85gHz ranges Cross track scanner : 32 sec sweep Swath width: 1500 km? Or 1400? Resolution: 12.5 to 25km |
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Special Sensor Microwave Temperature sounder (SSMT-1) Spectral Coverage: 7 channels in O2 absorption bands 50-60 ghz Cross track scanner : 32 sec sweep Swath width: 1500 km or 1400? Resolution: 250 km (nadir) to 480 km (edge of scan) Vertical coverage: sfc-30km |
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Special Sensor Microwave humidity sounder SSMT-2 Spectral Coverage: 1 window channel at 91.5 ghz, 2 low humidity windows at 150 ghz 3 water vapor absorption line Cross track scanner 8 sec sweep Swath width: 1500 km or 1400? Spatial Resolution: 60 km (nadir) to 120 km (edge of scan) Vertical coverage: sfc-10km |
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Special Sensor Microwave Imager Sounder suite (SSMIS) Beginning with the launch of F-16, DMSP is moving towards a better solution with the Special Sensor Microwave Imager Sounder (SSMIS) sensor. This sensor combines the capabilities of SSM/I, /T-1 & T-2, and includes the addition of a new temperature sounder for upper air into one complete package. This consolidation results in an increased amount of data channels. In addition, the SSMIS package will cover a wider footprint (i.e. swaths). Another added benefit of SSMIS is improved sounding resolution, going from 175km to 38km. Spectral Coverage 24 channels from 19 to 183ghz Concial scanner : 32 sec sweep Swath width: 1700 km Sounding Resolution: 38km Imager Resolution: 12.5 to 25km Vertical Coverage: Sfc-60km |
| OLS vs. SSM/I Imagery | |
| DMSP F13 OLS Visible | DMSP F13 SSM/I 85 GHz |
 This imagery of Hurricane Linda (14 September 1997) provides a great example of what SSM/I provides versus OLS. Through SSM/I, the weather forecaster can obtain better definition of the hurricane’s eye due to the ability to penetrate cloud cover. This allows forecasters to determine the location and size of the storm, both of which are critical parameters in determining the intensity of the storm. | |