Image Credit:
NASA's Goddard Space Flight
Center
Feature Link:
The most accurate and comprehensive collection of rain, snowfall and other
types of precipitation data ever assembled now is available to the public. This
new resource for climate studies, weather forecasting, and other applications is
based on observations by the Global Precipitation Measurement (GPM) Core
Observatory, a joint mission of NASA and the Japan Aerospace Exploration Agency
(JAXA), with contributions from a constellation of international partner
satellites.
The GPM Core Observatory, launched from Japan on Feb. 27, carries two
advanced instruments to measure rainfall, snowfall, ice and other precipitation.
The advanced and precise data from the GPM Core Observatory are used to unify
and standardize precipitation observations from other constellation satellites
to produce the GPM mission data. These data are freely available through NASA's
Precipitation Processing System at Goddard Space Flight Center in Greenbelt,
Maryland.
"We are very pleased to make all these data available to scientists and other
users within six months of launch," said Ramesh Kakar, GPM program scientist in
the Earth Science Division at NASA Headquarters, Washington.
One of the first storms observed by the NASA/JAXA
GPM Core Observatory on March 17, 2014, in the eastern United States revealed a
full range of precipitation, from rain to snow.
Image Credit:
NASA/JAXA
In addition to NASA and JAXA, the GPM mission includes satellites from the
U.S. National Oceanic and Atmospheric Administration, U.S. Department of
Defense's Defense Meteorological Satellite Program, European Organisation for
the Exploitation of Meteorological Satellites, Indian Space Research
Organisation, and France's Centre National d’Études Spatiales.
Instruments on the GPM Core Observatory and partner satellites measure energy
naturally emitted by liquid and frozen precipitation. Scientists use computer
programs to convert these data into estimates of rain and snowfall. The
individual instruments on the partner satellites collect similar data, but the
absolute numbers for precipitation observed over the same location may not be
exactly the same. The GPM Core Observatory's data are used as a reference
standard to smooth out the individual differences, like a principal violinist
tuning the individual instruments in an orchestra. The result is data that are
consistent with each other and can be meaningfully compared.
With the higher sensitivity to different types of precipitation made possible by the GPM Core Observatory's Microwave Imager (GMI) and Dual-frequency Precipitation Radar (DPR), scientists can for the first time accurately measure the full range of precipitation from heavy rain to light rain and snow. The instruments are designed not only to detect rain and snow in the clouds, but to measure the size and distribution of the rain particles and snowflakes. This information gives scientists a better estimate of water content and a new perspective on winter storms, especially near the poles where the majority of precipitation is snowfall.
With the higher sensitivity to different types of precipitation made possible by the GPM Core Observatory's Microwave Imager (GMI) and Dual-frequency Precipitation Radar (DPR), scientists can for the first time accurately measure the full range of precipitation from heavy rain to light rain and snow. The instruments are designed not only to detect rain and snow in the clouds, but to measure the size and distribution of the rain particles and snowflakes. This information gives scientists a better estimate of water content and a new perspective on winter storms, especially near the poles where the majority of precipitation is snowfall.
"With this GPM mission data, we can now see snow in a way we could not
before," said Gail Skofronick-Jackson, GPM project scientist at Goddard Space
Flight Center. "Cloud tops high in the atmosphere have ice in them. If the
Earth’s surface is above freezing, it melts into rain as it falls. But in some
parts of the world, it's cold enough that the ice and snow falls all the way to
the ground."
One of the first storms observed by the GPM Core Observatory on March 17 in
the eastern United States showed that full range of precipitation. Heavy rains
fell over the North and South Carolina coasts. As the storm moved northward,
West Virginia, Virginia, Maryland and Washington were covered with snow. The GMI
observed an 547 mile- (880 kilometer) wide track of precipitation on the
surface, while the DPR imaged every 820 feet (250 meters) vertically to get the
three-dimensional structure of the rain and snowfall layer by layer inside the
clouds.
"What's really clear in these images is the melting layer, the place in the
atmosphere where ice turns into rain," said Skofronick-Jackson. "The melting
layer is one part of the precipitation process that scientists don’t know well
because it is in such a narrow part of the cloud and changes quickly.
Understanding the small scale details within the melting layer helps us better
understand the precipitation process."
The combined snowfall and rainfall measurements from GPM will fill in the
picture of where and how water moves throughout the global water cycle.
"Scientists and modelers can use the new GPM data for weather forecasts,
estimating snowpack accumulation for freshwater resources, flood and landslide
prediction, or tracking hurricanes," Skofronick-Jackson said. "This
revolutionary information also gives us a better grasp of how storms and
precipitating systems form and evolve around the planet, providing climate
modelers insight into how precipitation might change in a changing climate."
GPM data are freely available to registered users from Goddard's
Precipitation Processing System (PPS) website. The data sets are currently
available in strips called swaths that correspond to the satellites' overpasses.
Daily and monthly, global maps are also available from all the sensors. In the
coming months, the PPS will merge this instrument data from all partner
satellites and the Core Observatory into a seamless map that shows global rain
and snow data at a 6-mile (10-kilometer) resolution every 30 minutes.
The GPM Core Observatory was the first of five scheduled NASA Earth science
missions launching within a year. NASA monitors Earth's vital signs from land,
air and space with a fleet of satellites and ambitious airborne and ground-based
observation campaigns. NASA also develops new ways to observe and study Earth's
interconnected natural systems with long-term data records and computer analysis
tools to better see how our planet is changing. The agency freely shares this
unique knowledge with the global community and works with institutions in the
United States and around the world that contribute to understanding and
protecting our home planet.
For more information about NASA's Earth science activities, visit:
For more information about GPM, visit:
To access the newly released data, visit:
NASA
Guillermo Gonzalo Sánchez Achutegui
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