Weather, Climate Satellite Constellation

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NASA Technology Spawns Weather, Climate Satellite Constellation

A globe-spanning constellation of six weather and climate research satellites based on a novel application of NASA-developed technology is set to launch from Vandenberg Air Force Base, Calif., Friday, April 14, at 5:10 p.m. PDT aboard a Minotaur rocket.

The Constellation Observing System for Meteorology, Ionosphere and Climate network, known as Cosmic in the United States and Formosat-3 in Taiwan, is expected to improve weather forecasts, monitor climate change and enhance space weather research.


Image above: Artist's concept of Constellation
Observing System for Meteorology, Ionosphere
and Climate.
Image credit: University Corporation for
Atmospheric Research
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NASA's Jet Propulsion Laboratory, Pasadena, Calif., designed Cosmic's primary instrument, a science global positioning system receiver, based on its proven BlackJack space receiver.

The five-year mission is a cooperative program between the American Institute in Taiwan and the Taipei Economic and Cultural Representative Office in the United States. It is funded by that office?s designated representative, Taiwan's National Space Organization, and various American Institute in Taiwan-designated representatives, including the National Science Foundation, Arlington, Va., which leads science activities. The University Corporation for Atmospheric Research, Boulder, Colo., manages the mission and designed the satellite array system.

The low-orbiting satellites will be the first to provide atmospheric data daily in real time over thousands of points on Earth. They will measure the bending of radio signals from the U.S. global positioning system as the signals pass through Earth's atmosphere, a technology known as radio occultation.

"Cosmic is a prime example of transitioning NASA remote sensing technology into operational weather forecasting," said Tony Mannucci, supervisor of JPL's Ionospheric and Atmospheric Remote Sensing Group. "The expected improvements in forecasting skill and Cosmic's contribution to long-term climate monitoring are a direct result of NASA's research investments in radio occultation, a technology originally developed by JPL in the 1960s for planetary atmospheric studies and later refined in the 1990s for Earth orbit use."

Temperature and water vapor profiles derived from the satellites will help meteorologists observe, research and forecast hurricanes, typhoons and other storm patterns over the oceans and improve many areas of weather prediction. The mission's stability, consistency and accuracy should be a boon to scientists quantifying long-term climate change trends.

The satellites are also expected to improve analysis and forecasting of space weather -- the geomagnetic storms that can interrupt sensitive satellite and communications systems and affect power grids.

While several single-satellite systems have used global positioning system signals experimentally over the past decade, Cosmic's satellite array is the first to provide the high-density global coverage required for both research and operational forecasting.

Orbiting 800 kilometers (500 miles) above Earth, the satellites will take about 2,500 measurements a day in a nearly uniform global distribution, providing independent data over vast ocean stretches where there are no weather balloons. Because its radio signals pierce thick cloud cover and precipitation, weather conditions will not interfere with data gathering. Mission data will be available to researchers and forecasters within a few hours of the observations.

Other major American Institute in Taiwan-designated representatives in Cosmic include the National Oceanic and Atmospheric Administration, U.S. Air Force Space Test Program and U.S. Air Force Space and Missile Systems Center Rocket Systems Launch Program, and the Office of Naval Research. The spacecraft was designed by Orbital Sciences Corporation. Broad Reach Engineering built the satellite constellation receivers. The Naval Research Laboratory designed and built the ionospheric sensors. The rest of the constellation was built and tested in Taiwan.

For more information on Cosmic on the Internet, visit:

http://www.cosmic.ucar.edu.

For more information on global positioning system occultation remote sensing, visit:

http://genesis.jpl.nasa.gov

Other points of contact include: Anatta, University Corporation for Atmospheric Research, Boulder, Colo., (303) 497-8604; and Cheryl Dybas, National Science Foundation, Arlington, Va., (703) 292-7734.

JPL is managed for NASA by the California Institute of Technology.

Media contact:
Alan Buis (818) 354-0474
Jet Propulsion Laboratory, Pasadena, Calif.

Erica Hupp/Dwayne Brown (202) 358-1237/1726
NASA Headquarters, Washington

2006-057

Source: NASA/JPL - News

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U.S.-Taiwan Satellite Constellation Launches

A globe-spanning constellation of six weather and climate research satellites based on global positioning system occultation technology developed at JPL successfully launched from Vandenberg Air Force Base, Calif., Friday, April 14, at 9:40 p.m. EDT (6:40 p.m. PDT) aboard a Minotaur rocket. The Constellation Observing System for Meteorology, Ionosphere and Climate network, or Cosmic, is expected to improve weather forecasts, monitor climate change and enhance space weather research during its five-year mission.


Image above: Launch of Cosmic. Image credit: Gene Blevins/LA Daily News
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For more information about the mission visit:
+ Pre-launch release
http://www.cosmic.ucar.edu
http://genesis.jpl.nasa.gov

Media contact:
Alan Buis (818) 354-0474
Jet Propulsion Laboratory, Pasadena, Calif

Source: NASA - Life On Earth - Looking At Earth

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Purveyors of the Cosmic 'Occult'

To a non-scientist, the words 'radio occultation' might sound a little spooky. But this relatively simple NASA-developed technology at the heart of a new satellite network named Cosmic is proving to be a powerful new tool for weather and climate forecasting.

Launched April 14, 2006, the six spacecraft of the Constellation Observing System for Meteorology, Ionosphere and Climate measure the bending and slowing of microwave radio signals as they pass through Earth's atmosphere. The signals are transmitted from U.S. global positioning system (GPS) satellites to Cosmic's GPS science receivers, which were designed by NASA's Jet Propulsion Laboratory. These bending and slowing events, referred to as occultations, occur when the GPS satellite signals are interrupted as the satellites rise or set on Earth's horizon, blocking their transmission.


Image above: Artist's concept of Constellation
Observing System for Meteorology, Ionosphere
and Climate.
Image credit: University Corporation for
Atmospheric Research
+ Larger view

By precisely measuring -- to a few trillionths of a second -- the time delay from this bending, scientists can infer information on atmospheric conditions such as air density, temperature, moisture, refractivity, pressure and electron density. This makes GPS radio occultation a powerful new tool for weather and climate forecasting and space weather research. Now, with Cosmic, the technology appears poised to take off.

A joint endeavor between several U.S. and Taiwanese agencies and institutions, Cosmic is currently feeding real-time, weather balloon-quality data on Earth's atmosphere every day, over thousands of points on Earth. Temperature and water vapor profiles derived from Cosmic will help meteorologists improve many areas of weather prediction and observe, research and forecast hurricanes, typhoons and other storm patterns over the oceans. Over time, the mission should be a boon to scientists studying long-term climate change trends. Cosmic data will also help improve forecasting of space weather -- the geomagnetic storms in Earth's ionosphere (the part of our atmosphere filled with electrically charged particles). Those storms can disrupt communications around the world and affect electrical power grids.

Cosmic blends with existing observing systems, filling in major gaps and enhancing computer-generated forecast models. "Through Cosmic, radio occultation is at last emerging from the laboratory and is being embraced by the worldwide weather and climate community," said Tom Yunck, a researcher in JPL's Instruments and Data Systems Division and a key member of the JPL team behind Cosmic's radio occultation technology. "Nearly all developed countries and major weather services are researching these data and learning how to ingest them into forecasts."

A Technology Whose Time Has Come

GPS occultation has many advantages. It can probe Earth's atmosphere from the top of the stratosphere (50 kilometers, or 30 miles up) directly to Earth's surface with extreme precision. It can operate in all weather conditions, penetrating the thickest clouds. And it is relatively inexpensive. GPS receivers, comparable in size and complexity to notebook computers, can be built for a fraction of the cost of traditional spaceborne sensors and placed unobtrusively on many low-orbiting spacecraft.


Image above: Hurricane Frances, as observed
by NASA's Spaceborne Atmospheric Infrared
Sounder and SeaWinds Scatterometer.
Image credit: NASA/JPL
+ Larger view

Since most Earth satellites already carry such devices for timing and navigation, upgrading those instruments for science purposes might ignite a revolution in Earth remote sensing. A single GPS receiver in low Earth orbit can acquire more than 500 measurements of atmospheric conditions at various heights every day, spread nearly uniformly across the globe. This is comparable to the number of weather balloons launched worldwide every 12 hours.

Unlike other remote sensing techniques, occultation measurements don't require calibration as the instruments age. This means measurements made today can be compared to measurements 20 to 30 years from now without any concern about measurement drifts and errors.

"There's an urgent need for very accurate, stable climate records that can be relied on for decades to come," said Tony Mannucci, supervisor of JPL's Ionospheric and Atmospheric Remote Sensing Group. "We expect constellations such as Cosmic will continue to be deployed and that we can establish a long-term, stable and accurate atmospheric temperature record that the scientific community wants and needs."

History

The roots of GPS sounding date back to the first days of interplanetary exploration. To learn more about the history of GPS occultation research leading up to Cosmic, click here .

Cosmic Status

Seven months after launch, all six Cosmic spacecraft and their payloads are healthy. Maneuvers continue to move the satellites into their final orbits 800 kilometers (500 miles) above Earth, in six different orbital planes. The satellites are averaging about 1,200 soundings a day, in a nearly uniform global distribution, providing independent data over vast stretches of ocean and ice where there are no weather balloons. As the satellites approach their final positions, they will increase their output to about 2,500 soundings a day.

Cosmic data became available to the public on July 28. JPL and its partners have begun processing Cosmic data into temperature and water vapor profiles of the atmosphere and measurements of the electron content of the ionosphere.

The capability of GPS to deliver high-quality measurements despite thick cloud cover is proving to be a major advantage. Preliminary results suggest Cosmic data will improve prediction of hurricane tracks, including where and when they will hit land.

It's too soon to say exactly how much impact Cosmic will have on daily weather forecasting, but the early evidence is that it will be large. "Even a one-percent improvement would be considered a big impact," said George Hajj, supervisor of JPL's Orbiter and Radio Metric Systems Group. "It's expected that Cosmic-like data will become one of the main data streams for weather centers worldwide.” In fact, the U.S. National Oceanic and Atmospheric Administration will begin using Cosmic data in their operational forecasts in January 2007, and Canada will follow next spring.

NASA has announced the availability of grants to advance GPS remote sensing science through the analysis of Cosmic and related data sets. JPL has also begun developing a third-generation Global Navigation Satellite System receiver that will use the vastly expanded signals expected in the next 10 years from the next-generation GPS satellites; the rejuvenated Russian Global Navigation Satellite System satellites, known as GLONASS; and the European Galileo system.

For more information on Cosmic on the Internet, visit: http://www.cosmic.ucar.edu. For information on GPS occultation remote sensing, visit: http://genesis.jpl.nasa.gov.

Media contacts: Alan Buis 818-354-0474
Jet Propulsion Laboratory, Pasadena, Calif

Source: NASA - Life On Earth - Looking At Earth