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NASA launches game-changing satellite for tracking global precipitation

2:05 p.m. update: Video of launch…

NASA and JAXA launch the Global Precipitation Measurement (GPM) Core Observatory in a H-IIA vehicle at the Japan Aerospace Exploration Agency (JAXA) Tanegashima Space Center in Tanegashima Island, Japan. (Video: NASA)

1:40 p.m. update: The launch appears to have occurred successfully.

From 1:05 p.m.: At 1:37 p.m. today, NASA and the Japan Aerospace Exploration Agency plan to launch a weather and climate satellite that will revolutionize our understanding and ability to monitor global precipitation.  Known as the Global Precipitation Measurement (GPM) satellite,  it will – for the first time – provide a near global map of rain and snow falling within 3 hours.

Think of the radar map over your local area, but extended over most of the world.

This satellite mission will help fill massive gaps in precipitation observations as large areas of the Earth’s land and ocean don’t have radar or rain gauges.

The satellite has unprecedented range (for sensing precipitation), and will scan the skies between the Arctic and Antarctic circle, or between 65 degrees north and south latitude.

Video: NASA scientist Dalia Kirschbaum discusses the value of this satellite

NASA’s current satellite for research and monitoring precipitation, known as the Tropical Rainfall Measuring Mission (TRMM), only takes measurements between 35 degrees north and south.

When Hurricane Sandy charged from the Atlantic waters off the Southeast coast into the Mid-Atlantic, TRMM could no longer observe the storm – missing the opportunity to observe the storm’s transition from a tropical to mid-latitude storm.

“GPM will be able to observe the extratropical transition [of hurricanes], something we’ve never been able to do before in three dimensions,” said NASA’s Dalia Kirschbaum, GPM project scientist, in an interview with the Capital Weather Gang.

The satellite is equipped with two instrument systems: a radiometer and dual-frequency radar that will scan the skies and ping back to earth information about the structure, intensity and amount of precipitation.

Whereas TRMM can only detect rain, GPM can detect and differentiate rain, ice and snow – and their varying intensities.

“GPM has the most advanced instruments to measure precipitation from space that we’ve ever had,” said Kirschbaum. “It also provides the most accurate global picture and dataset of rain and snow that we’ve ever had.”

GPM’s 13 channel microwave radiometer surveys the skies in 32 rotations per minute. Kirschbaum explained it operates like an X-ray. “It can differentiate between liquid water versus ice – you get the bones, muscles and tissues,” she said.

The dual-frequency radar aboard the satellite will be the first of its kind in space.

“It looks every 250 meters, layer by layer, through clouds,” Kirschbaum said. “It’s able to discern particle distribution, and type.  By having 2 frequencies, we’ll be able to get a much better understanding of what’s there which is important for weather forecasting and climate modeling.”

Perhaps GPM’s most valuable asset – the ability to provide a near global view of precipitation and intensity within a few hours – cannot be achieved by the satellite itself. Rather, the data collected by GPM’s radiometer will be used to calibrate measurements from a constellation of other satellites which remotely sense precipitation.

“Observations from its radiometer will act as the standard to unify all the other satellite measurements,” writes NASA’s Ellen Gray, the science writer for the mission.

NASA’s Kirschbaum believes GPM’s global precipitation mapping capabilities will prove invaluable for disaster response and famine early warning systems.

“The data is important on a local scale so responders can anticipate where we might be experiencing food shortage and respond accordingly,” she said. “They need to have the vantage point from space to get that global picture.”

Kirschbaum said it may be a number of months before the global mapping capabilities of GPM reach the public. The data have to be first checked for a quality and the GPM database for calibrating measurements from other satellites will require time to build.

“Data will then be freely available to anyone in the world, all processed at NASA Goddard, and distributed in different formats so most people have access,” she said.

You can follow the launch coverage on NASA TV, @NASA_Rain on Twitter and on Facebook.

Mashable’s Andrew Freedman has more information on the mission.