CEOS Instrument: TRMM Microwave Imager




Instrument:TMI
Agency: NASA
Mission: TRMM
Status:Operational
Type:Multi-purpose imaging MW radiometer
Description:Measures rainfall rates over oceans (less reliable over land), combined rainfall structure and surface rainfall rates with associated latent heating. Used to produce monthly total rainfall maps over oceans
Spatial Resolution: Vertical: 2.5 km approx; Horizontal: 18 km
Swath Width: 790 km
Wavebands: Microwave: 10.7 GHz, 19.4 GHz, 21.3 GHz, 37 GHz, and 85.5 GHz
Technology: Multi-purpose imaging MW radiometer
Description: Radiometer operating in bands of frequency ranging from 1 to 300 GHz. A specific instrument can only cover a limited part of the range, for instance from 7 to 200 GHz. Several parameters can be observed in this range, thus the instrument is designed by optimally blending the various features. For certain parameters very low frequencies are need (e.g., 1.4 GHz for ocean salinity and soil moisture in the roots region). Several channels, of bandwidths often constrained by frequency protection regulations. The basic channels operate in atmospheric windows, but in few cases absorption channels also are added. Conical scanning is the rule, that enables constant incidence angle, thus homogeneous polarisation conditions. If full polarisation is implemented, the instrument provides sea-surface wind vector. The resolution is diffraction-limited, thus for a given antenna (e.g., diameter 180 cm) changes with frequency (e.g., from 4 to 50 km moving frequency from 90 to 7 GHz). For very low frequencies, synthetic

Measurement List:

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CEOS Systems Engineering Office (SEO)

CEOS Data Base Version: 17 - Created: 2012-01-18