Global Precipitation Measurement-Microwave Imager
Ball Aerospace’s Global Precipitation Measurement-Microwave Imager (GMI) will play an essential role in the Earth’s weather and environmental forecasting.
The GMI supports the Global Precipitation Measurement (GPM) mission, which is a joint effort between NASA and the Japan Aerospace Exploration Agency (JAXA) to improve climate, weather and rainfall predictions by providing more accurate precipitation measurements from space.
GMI will work in concert with the JAXA-built Dual-Frequency Precipitation Radar (DPR) instrument. GMI’s higher frequency channels will measure small particles of ice, snow and rain while DPR gives a three-dimensional view of a column of precipitation. Together, these instruments give scientists an unprecedented view of small precipitation particles with a much higher degree of accuracy.
With less than two percent of the Earth’s total water volume being potable, the scientific community has long been committed to acquiring precipitation information.
The GPM satellite successfully launched from Tanegashima Space Center on Tanegashima Island in southern Japan at 1:37 pm EST on February 27, 2014. The satellite was launched onboard an H-IIA launch vehicle.
Ball Aerospace’s role in the GPM program includes the design, development and fabrication of the GMI. Operating at 32 revolutions per minute, GMI is a powerhouse of radiometry, using four very stable calibration points on each revolution to regulate the scanned data. GMI collects Earth brightness temperature data from different locations at numerous sampling times throughout each 90-minute orbit and downloads the data every three hours. The GPM satellite has an unusual orientation to the sun, so Ball engineers designed the eight-foot tall GMI to minimize solar intrusion, which creates errors in science data.
Ball’s ingenious design provides a high level of accuracy, which allows GMI to cross-calibrate other sensors in the GPM constellations, setting a new reference standard for the scientific community.
GMI/NASA image showing rain rates across a 550-mile (885 kilometer) wide swath of an extra-tropical cyclone observed off the coast of Japan on March 10, 2014. Red areas indicate heavy rainfall, while yellow and blue indicate less intense rainfall. The upper right blue areas indicate falling snow.
NASA image of GPM/GMI collecting 37 GHz horizontally polarized Brightness Temperature data (colored in shades of aquamarine) on March 10th over a Pacific storm east of Japan.