[env-trinity] Atmospheric observatory slated for Humboldt

[Mark Dowdle - TCRCD]

*Atmospheric observatory coming to Humboldt;
equipment in **Eureka**area will help meteorologists
better gauge big winter storms*

John Driscoll/The Times-Standard

Posted: 02/15/2011 01:30:23 AM PST

The National Oceanic and Atmospheric Administration plans to build a 
high-tech
meteorological observatory in the Eureka area that should help 
forecasters better understand the source of California's largest storms.

The observatory would be one of four on the California coast that will 
be part of a study of so-called atmospheric rivers, which transport massive
amounts of water across the Pacific Ocean before dumping it on land. The 
agency is looking to improve forecasts for storms that might lead to 
flooding, landslides and severe winds.

The Eureka-area observatory could begin to be built about a year from 
now, said NOAA research meteorologist Allen White. The unmanned 
equipment will include Doppler wind-profiling radar, GPS and a 
meteorological tower, all of which allow meteorologists to determine the 
speed of winds in an atmospheric river and how much water vapor the 
winds are transporting. NOAA plans to place other observatories in the 
Bodega Bay, Big Sur and Santa Barbara areas.

Atmospheric rivers are ribbons of air between 300 and 500 km wide -- 
about 186 to 310 miles -- that form off cyclones or draw moisture from 
over the ocean. "In essence, they are rivers in the sky," said Marty 
Ralph, chief of the Water Cycle Branch in NOAA's Physical Science Division.
Atmospheric rivers are responsible for carrying about 90 percent of the 
water vapor in the Northern Hemisphere, Ralph said. A series of them 
brought 11 to 25 inches of rain to areas of California in mid-December 
and dumped huge amounts of snow in the Sierra Nevada at the time.

Scientists can see these rivers from space using satellites, but those 
instruments are unable to measure wind speed or water vapor content. The 
land-based observatories are able to do both, giving meteorologists a 
way to check computer
forecast models regarding atmospheric rivers.

Ralph said that a better understanding of wind speed and water vapor 
content in the atmospheric rivers will help give a better picture of 
what to expect when the rivers flow over land.

Ralph said that both the speed of the wind and the amount of moisture in 
a river dictate how much precipitation will fall when the river hits a 
mountain range. When the air hits the mountains, it rises and cools, 
condensing the water vapor and causing rainfall. The faster the wind, 
the more rain, and the more moisture, the more rain.

NOAA also plans to use unmanned aircraft that can fly for 24 hours or 
more and travel at very high and low altitudes. The aircraft will have 
on board advanced water vapor sensors and dropsondes -- devices that 
will measure temperature, wind and other factors when they are dropped.

The state Department of Water Resources will use the information gleaned 
from the overall project to improve flood response and emergency 
preparedness.

White said that NOAA will be scouting locally for an area to place the 
atmospheric rivers observatory -- which is only about 20 feet by 20 feet 
-- sometime within the next six months.


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