DMSP Satellite Microwave Brightness Temperature Measurements

Seven-channel passive microwave radiometer data captures atmospheric, ocean, and terrain brightness temperatures at four frequencies. The instrument performs a conical scan across a 1,400 km swath, with geolocated antenna temperatures archived by orbit. Data originates from the SSM/I instrument on Defense Meteorological Satellite Program (DMSP) platforms, processed and archived by NOAA's National Centers for Environmental Information.

Use Cases

• Retrieve global sea ice concentration by analyzing the polarization difference at 19.35 GHz and 37.0 GHz channels.
• Estimate integrated atmospheric water vapor using brightness temperature measurements from the 22.235 GHz channel.
• Detect precipitation and cloud liquid water by examining emission and scattering signatures across the 85.5 GHz and lower-frequency channels.
• Generate synoptic maps of land surface parameters like soil moisture by comparing vertically and horizontally polarized data at 19.35 GHz.
• Correct for ionospheric scintillation effects by identifying and adjusting for the 1.8-3.4% rate of bit reversals encountered during decommutation.

Strengths

• Provides multi-frequency measurements at 19.35, 22.235, 37.0, and 85.5 GHz with dual polarization for physical parameter retrieval.
• Offers high spatial resolution for the 85.5 GHz channel with a 13 x 15 km footprint, sampled 128 times per scan.
• Includes geolocation for each pixel using computed satellite ephemeris and attitude corrections.

Limitations

• Footprint size varies significantly by channel and scan position, from 13x15 km at 85 GHz to 43x69 km at 19 GHz, complicating direct pixel-to-pixel comparison.
• Data processing requires a complete 28-second cycle of scans from all channels, making partial data unusable.
• The raw data ingestion method from AFWA via a T-1 line may indicate legacy transmission and formatting constraints.

Provenance

Source

Defense Meteorological Satellite Program (DMSP) SSM/I instrument, processed and archived by NOAA National Centers for Environmental Information.

Collection Method

Passive microwave radiometry from a satellite-borne, conically scanning instrument measuring emitted radiation; data is decommutated, geolocated, and calibrated into orbital files.

Time Range

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Freshness

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Geography

Global scale, from a 1,400 km conical scan with a consistent Earth incidence angle of 53.1 degrees.