FW: CloudSat set to bust clouds' cover

[Guest guest]

Pay special attention to the use of the word "Aerosols" in this

report!

 

 

13:06 20 April 2006

NewScientist.com news service

Kelly Young

 

 

After months of delays, NASA is preparing to launch a pair of

satellites that will peer inside clouds to help produce more

accurate models of the Earth's changing climate.

The satellites are scheduled to lift off aboard a Delta 2 rocket

from Vandenberg Air Force Base in California, US, at 0302 PDT on

Friday. It had been aiming to launch in 2005 but strikes by Boeing

workers, who prepare the rocket for flight, created delays.

One satellite, CloudSat, will be one thousand times more sensitive

than existing weather radar and be able to probe the internal

structure of clouds – existing satellite weather radar can image

only the cloud tops.

"CloudSat's going to be able to fill in that three-dimensional

information that we don't have now," says Tom Livermore, the

CloudSat project manager with NASA's Jet Propulsion Laboratory in

Pasadena, California.

Rain and snow Its heightened sensitivity comes in part because it

is equipped with a stronger transmitter and a larger, 1.85-metre-

long antenna. And its 94-gigahertz frequency will allow the radar to

penetrate the thickest clouds. The existing Tropical Rainfall

Measuring Mission satellite operates at 14 gigahertz.

Graeme Stephens, CloudSat's lead scientist with Colorado State

University, US, says he is excited to learn what fraction of clouds

produce rain and snow. "That's pretty darn elementary because that

tells us a lot about the water cycle of the planet and how it might

change with global warming," he says.

Cloudsat's companion, CALIPSO (Cloud-Aerosol Lidar and Infrared

Pathfinder Satellite Observations), will measure the distribution of

aerosol particles and thin clouds in the atmosphere. Lidar is

similar to radar, but uses optical light from lasers instead of

microwaves.

Six in a row Aerosols are important as they can reflect light

from the Sun, cooling the planet. They can also seed clouds. Current

technology can tell where aerosols are over the Earth but not their

altitude above the surface. Scientists want to know how aerosols and

clouds interact, the level of aerosols produced by humans and

nature, and how aerosols travel in the atmosphere.

The satellites will fly 15 seconds apart from one another and join

three other US and French Earth-observing spacecraft in the same

orbit. They will later be accompanied by a sixth satellite to

monitor atmospheric carbon dioxide.

The six will fly one after the other in a line, in a constellation

dubbed the A-Train, with all of them focusing their observations on

the same swath of the Earth at any one time.

 

Link:>http://www.newscientistspace.com/article/dn9024-cloudsat-set-

to-bust-clouds-cover.html