Box 3-E--DoD's Defense Meteorological Satellite Program

Since the mid 1960s, the Defense Meteorological Satellite Program (DMSP) has provided military commanders with accurate and up-to-date weather information. It began after DoD argued for a satellite to provide reliable and unique weather data in support of U.S. troops involved in exercises or stationed in remote locations that ladk other sources of weather information.

Each current DMSP block 5D-2 satellite flies in a polar orbit at an altitude of 832 km (530 miles), and views the entire globe twice per day. The satellites use optical and infrared sensors, which cover a ground swath of just under 3,000 km:

The Operational Linescan System (OLS), a visible and infrared imager that monitors cloud cover, has three spectral bands. OLS operates at high spatial resolution (.6 km) about 25 percent of the time.

The Microwave Imager (a radiometer used for determining soil moisture, precipitation, and ice cover) has four channels, and a spatial resolution of 25-50 km.

The Microwave Temperature Sounder, used for vertical temperature sensing, has seven channels.

The Microwave Water Vapor Sounder, used for determining humidity through the atmosphere, has five channels and spatial resolution between 40 and 120 km.

The satellites are capable of storing up to 2 days' worth of data before downloading to ground stations located at Fairchild AFB, Washington, and Kaena Point, Hawaii. There are currently two of the block 5D-2 satellites in operation, and a new block upgrade is currently in development. The bus, the structural element of the satellite that carries and powers the sensors, is similar to the bus used for the TIROS satellites.

Since 1975, the Navy, Air Force, and NOM have coordinated data processing efforts and exchanged meteorological data through a shared processing network. Each of the processing centers has a particular expertise: NOM for atmospheric soundings; Navy for sea surface measurements and altimetry; and Air Force for visible and infrared mapped imagery and doud imagery. The focus on each area of expertise is designed to limit duplication and ensure cooperation. NOAA's National Environmental Satellite, Data, and Information Service archives the data processed by all three organizations.

SOURCE: U.S. Department of Defense, 1993.