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First Images Available from NASA-JAXA Global Rain and Snowfall Satellite
March 25, 2014
WASHINGTON, March 25, 2014 -- NASA and the Japan Aerospace Exploration Agency (JAXA) have released the first images captured by their newest Earth-observing satellite, the Global Precipitation Measurement (GPM) Core Observatory, which launched into space Feb. 27.
The images show precipitation falling inside a March 10 cyclone over the
northwest Pacific Ocean, approximately 1,000 miles east of Japan. The data were
collected by the GPM Core Observatory's two instruments: JAXA's Dual-frequency
Precipitation Radar (DPR), which imaged a three-dimensional cross-section of the
storm; and, NASA's GPM Microwave Imager (GMI), which observed precipitation
across a broad swath.
"It was really exciting to see this high-quality GPM data for the first time,"
said GPM project scientist Gail Skofronick-Jackson at NASA's Goddard Spaceflight
Center in Greenbelt, Md. "I knew we had entered a new era in measuring
precipitation from space. We now can measure global precipitation of all types,
from light drizzle to heavy downpours to falling snow."
The satellite's capabilities are apparent in the first images of the cyclone.
Cyclones such as the one imaged -- an extra-tropical cyclone -- occur when
masses of warm air collide with masses of cold air north or south of the
tropics. These storm systems can produce rain, snow, ice, high winds, and other
severe weather. In these first images, the warm front ahead of the cyclone shows
a broad area of precipitation -- in this case, rain -- with a narrower band of
precipitation associated with the cold front trailing to the southwest. Snow is
seen falling in the northern reaches of the storm.
The GMI instrument has 13 channels that measure natural energy radiated by
Earth's surface and also by precipitation itself. Liquid raindrops and ice
particles affect the microwave energy differently, so each channel is sensitive
to a different precipitation type. With the addition of four new channels, the
GPM Core Observatory is the first spacecraft designed to detect light rain and
snowfall from space.
In addition to seeing all types of rain, GMI's technological advancements allow
the instrument to identify rain structures as small as about 3 to 9 miles (5 to
15 kilometers) across. This higher resolution is a significant improvement over
the capability of an earlier instrument flown on the Tropical Rainfall
Measurement Mission in 1997.
"You can clearly see them in the GMI data because the resolution is that much
better," said Skofronick-Jackson.
The DPR instrument adds another dimension to the observations that puts the data
into high relief. The radar sends signals that bounce off the raindrops and
snowflakes to reveal the 3D structure of the entire storm. Like GMI, its two
frequencies are sensitive to different rain and snow particle sizes. One
frequency senses heavy and moderate rain. A new, second radar frequency is
sensitive to lighter rainfall and snowfall.
"Both return independent measurements of the size of raindrops or snowflakes and
how they are distributed within the weather system," said DPR scientist Bob
Meneghini at Goddard. "DPR allows scientists to see at what height different
types of rain and snow or a mixture occur -- details that show what is happening
inside sometimes complicated storm systems."
The DPR data, combined with data from GMI, also contribute to more accurate rain
estimates. Scientists use the data from both instruments to calculate the rain
rate, which is how much rain or snow falls to Earth. Rain rate is one of the
Core Observatory's essential measurements for understanding where water is on
Earth and where it's going.
"All this new information comes together to help us better understand how fresh
water moves through Earth's system and contributes to things like floods and
droughts," said Skofronick-Jackson.
GMI was built by Ball Aerospace & Technologies, Corp., in Boulder, Colo., under
contract to NASA. DPR was developed by JAXA with the National Institute of
Information and Communication Technology.
These first GPM Core Observatory images were captured during the first few weeks
after launch, when mission controllers at the NASA Goddard Mission Operations
Center put the spacecraft and its science instruments through their paces to
ensure they were healthy and functioning as expected. The engineering team
calibrates the sensors, and Goddard's team at the Precipitation Processing
System verifies the accuracy of the data.
For more information on the GPM mission, visit:
The GPM Core Observatory was the first of five planned Earth science launches
for the agency in 2014. The joint NASA/JAXA mission will study rain and snow
around the world, joining with an international network of partner satellites to
make global observations every three hours.