A new satellite designed to take detailed, near real-time measurements of rain and snowfall on a global scale whilst mapping the interior of storm systems is set to launch. The Global Precipitation Measurement (GPM) Core Observatory has been in development since 2005 and is a collaboration project between NASA and the Japanese Space Agency (JAXA). The satellite is due to be launched on the Japanese manufactured H-IIA delivery vehicle from the Tanegashima Space Centre, Tanegashima Island, Japan, on February 27.

Designed to work in conjunction with a network of existing and planned satellites, the GPM will fly 407 km (253 miles) above the Earth in an orbit inclined 65-degrees to the equator, giving it the ability to provide near real-time observations of rain and snow every three hours for anywhere on the planet. Its ability to survey a greater area than ground based devices will provide a more complete picture of global precipitation. It can also assess precipitation in areas which would be difficult to reach from the ground such as high altitudes or remote areas.

The GPM mission is the successor to the Tropical Rainfall Measuring Mission (TRMM), which launched in 1997, and was the first satellite to measure rainfall in the tropics during different points in the day. This system of observation proved itself to be a significant improvement over previous techniques when monitoring extreme weather events such as tropical storms which can pose a very real danger to human life.

The GPM satellite uses the same sampling method as its predecessor, building upon its technology. It is equipped with a microwave radiometer which is used to measure the quantity and intensity of rain and snowfall, and also carries a dual-frequency radar with the ability to peer within the particles of a cloud system and send back highly detailed data of each individual cloud layer.

GPM's shipping container being unloaded from the U.S. Air Force C-5 cargo plane that carried it to Japan (Photo: NASA)

Furthermore, for the first time, the state of the art sensor suite sported on the GPM core observatory satellite has the capability to detect falling snow and light rain. This is a significant step forward in the observation of precipitation, as the inability to detect certain forms of precipitation such as snow represented a significant blind spot in any previous efforts to create a truly global observation system, as it is these types of precipitation that are more likely to occur in higher latitudes.

The GPM mission has many real world applications regarding observing the impact of differing levels of precipitation on the environment. It should prove to be a great asset in assessing global water cycles, which in turn can have a pronounced effect on agricultural output. The system could also provide greater warning for extreme weather systems such as floods and hurricanes. This would grant those in the path of such a storm more time to evacuate and therefore minimize the loss of life.

The satellite core has recently undergone its final testing period, which involved switching on all of its systems for the first time since its journey to the launch site. The process was completed with no significant problems leaving the GPM on schedule for launch.

The satellite is due to commence normal operations about 60 days after launch, with the data it collects to be processed and distributed over the internet.

The video below outlines the GPM mission.

Source: NASA

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