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Elvia H. Thompson
Headquarters, Washington              Jan. 29, 2003
(Phone: 202/358-1696)

Rob Gutro
NASA Goddard Space Flight Center, Greenbelt, Md.
(Phone: 301/286-4044)

RELEASE: 03-025

NASA JOINS SNOW STUDY OVER THE SEA OF JAPAN

     NASA and two Japanese government agencies are collaborating on a 
snowfall study over Wakasa Bay, Japan. Using NASA's Earth Observing 
System Aqua satellite, research aircraft and coastal radars to gather 
data, the joint effort is expanding scientific knowledge about where 
precipitation falls.

Until now, the north Pacific's contributions to the global hydrologic 
cycle have been difficult to quantify. Precipitation measurements by 
satellite over open water are very important, because there are very 
few other ways to obtain the data. Snowfall is particularly difficult 
to measure from space even over the relatively uniform background of 
the ocean. New satellite instruments, that can detect precipitation 
over water, will give scientists data to help interpret how the 
hydrology of the Pacific Ocean impacts the U.S. and the world.

The Wakasa Bay Field Campaign is a combined research effort among 
NASA, the National Space Agency of Japan (NASDA), and the Japanese 
Meteorological Research Institute (MRI). The campaign began January 3 
and runs through February 14. 

"These experiments are critical to understanding whether the current 
El Nino event, for instance, actually increases global precipitation 
or merely redistributes it between land and ocean regions," said Tom 
Wilheit, Mission Scientist from Texas A&M University.

Wakasa Bay, located North of Osaka on the Sea of Japan, is known for 
its diverse weather in winter months. Ranging from extreme cold, that 
brings Siberian air and accompanying snow into the region, to fast 
moving extra-tropical low pressure systems, that consist primarily of 
rain at the surface, but originating as snowfall at higher altitudes.

A NASA P-3 Orion aircraft, from Wallops Island, Va., is flying over 
the bay and collecting data on snowfall and rainfall to compare to 
data being gathered by the Aqua satellite orbiting over the same area. 
The aircraft payload consists of five microwave sensors, each capable 
of uniquely observing precipitation and cloud properties.

On board Aqua is a Japanese-built Advanced Microwave Scanning 
Radiometer-Earth Observing System (AMSR-E) instrument. "With AMSR-E on 
Aqua, we're able to extend the high quality precipitation measurements 
from the Tropical Rainfall Measuring Mission satellite to beyond the 
tropics, in fact into both the mid-and high latitudes," said Claire
Parkinson, Aqua Project Scientist at NASA's Goddard Space Flight 
Center, Greenbelt, Md.

Some of the measurements will also be used for another field campaign 
concerning sea ice in the Sea of Okhotsk and to compare with data from 
the AMSR instrument aboard the Japanese ADEOS-II satellite.

The Wakasa Bay experiment is designed to test the calculations and 
methods that scientists use to process satellite data. The P-3 Orion 
observations will be used to get precise values for the cloud and 
precipitation properties, such as the size distribution of the ice
particles or raindrops, that are currently assumed in the satellite 
calculations. By replacing the assumed data with precise observations 
from the P-3, scientists can determine the accuracy of the Aqua AMSR-E 
rainfall and snowfall estimates.

"This mission will be helpful in understanding the north Pacific, 
because there is simply no place in this vast stretch of ocean where 
surface observations can be taken. Despite its remoteness, the ocean's 
size makes it an important player in the global hydrologic cycle that 
must be properly quantified to make progress in the global sense,"
said Christian Kummerow, Atmospheric Scientist at Colorado State 
University, Boulder, Co., one of the leaders of this mission.

NASA's Aqua satellite was launched on May 4, 2002. The Aqua mission 
provides a multi-disciplinary study of the Earth's atmospheric, 
oceanic, cryospheric, and land processes and their relationship to 
global change.

For more information and images, see:
http://www.gsfc.nasa.gov/topstory/2003/0122japansnow.html

Experiment website:
http://rain.atmos.colostate.edu/Wakasa

For the Aqua website:
http://aqua.nasa.gov

For the AMSR-E instrument website:
http://aqua.nasa.gov/AMSRE3.html

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