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Elvia H. Thompson
Headquarters, Washington              April 24, 2003
(Phone: 202/358-1696)

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

RELEASE: 03-146

HURRICANE WINDS CARRIED OCEAN SALT & PLANKTON FAR INLAND

     Researchers found surprising evidence of sea salt and 
frozen plankton in high, cold, cirrus clouds, the remnants 
of Hurricane Nora, over the U.S. plains states. Although the 
1997 hurricane was a strong eastern Pacific storm, her high 
ice-crystal clouds extended many miles inland, carrying 
ocean phenomena deep into the U.S. heartland.

Kenneth Sassen of the University of Utah, Salt Lake City, 
and University of Alaska Fairbanks; W. Patrick Arnott of the 
Desert Research Institute (DRI) in Reno, Nev.; and David O. 
Starr of NASA's Goddard Space Flight Center, Greenbelt, Md., 
co-authored a paper about Hurricane Nora's far-reaching 
effects. The paper was published in the April 1, 2003, issue 
of the American Meteorological Society's Journal of 
Atmospheric Sciences.

Scientists were surprised to find what appeared to be frozen 
plankton in some cirrus crystals collected by research 
aircraft over Oklahoma, far from the Pacific Ocean. This was 
the first time examples of microscopic marine life, like 
plankton, were seen as "nuclei" of ice crystals in the 
cirrus clouds of a hurricane. 

Nora formed off the Panama coast, strengthened as it 
traveled up the Baja Peninsula, and the hurricane crossed 
into California in September 1997. Over the western U.S., 
Nora deposited a stream of high cirrus, ice crystal, clouds 
that created spectacular optical effects, such as arcs and 
halos, above a broad region including Utah and Oklahoma. 
That stream of cirrus clouds enabled researchers to analyze 
growth of ice crystals from different nuclei. 

Different nuclei, like sulfate particles, sea salt and 
desert dust, affect ice-crystal growth and shape. Torn from 
the sea surface by strong hurricane winds, sea salt and 
other particles from evaporated sea spray are carried to the 
cold upper troposphere in storm updrafts, 
where the drops freeze and become ice crystals. Plankton, a 
microscopic organism, is also likely present in the sea 
spray and is similarly lofted to high levels.

"Understanding how ice crystals grow and what determines 
their shapes is important in understanding how they interact 
with sunlight and infrared energy," Starr noted. "These 
interactions are important processes in the global climate 
system. They are also critical to sensing cloud properties 
from space, where NASA uses measurements of the reflected 
solar radiation to infer cloud physical properties, such as 
ice-crystal size," he said.

Data were gathered using ground-based remote sensors at the 
Facility for Atmospheric Remote Sensing in Salt Lake City 
and at the Clouds and Radiation Testbed in northern 
Oklahoma.  A research aircraft collected particle samples 
over Oklahoma. Observations from the Geostationary 
Operational Environmental Satellite 9 (West), launched by 
NASA and operated by the National Oceanic and Atmospheric 
Administration, were also used. DRI analyzed the ice 
crystals collected from Nora.

Scientists were using data generated through the U.S. 
Department of Energy (DOE) Atmospheric Radiation Measurement 
(ARM) Program. The ARM Program's purpose is obtaining field 
measurements and developing computer models of the 
atmosphere. Researchers hope to better understand the 
processes that control the transfer of solar and thermal 
infrared energy in the atmosphere, especially in clouds, and 
at the Earth's surface.

The ARM energy measurements also double-check data from the 
Moderate Imaging Spectroradiometer instrument aboard NASA's 
Terra and Aqua satellites. By ensuring the satellites are 
recording the same energy reflected and absorbed by clouds 
from Hurricane Nora as those provided by the ground data in 
this study, scientists hope to take fewer ground 
measurements in the future, and enable the satellites to 
provide the data.

The DOE ARM program, National Science Foundation, and NASA's 
Earth Science Enterprise funded this research. The Earth 
Science Enterprise is dedicated to understanding the Earth 
as an integrated system and applying Earth System Science to 
improve prediction of climate, weather and natural hazards, 
such as hurricanes, using the unique vantage point of space.

For more information and images on the Internet, visit:
http://www.gsfc.nasa.gov/topstory/2003/0408plankton.html

For information about the various agencies and programs 
mentioned above on the Internet, visit:

U.S. Department of Energy: Atmospheric Radiation Measurement 
Program
http://www.arm.gov/

National Hurricane Center: Hurricane Nora Report
http://www.nhc.noaa.gov/1997nora.html

NASA's GOES Satellite Data:
http://rsd.gsfc.nasa.gov/goes/

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