Colorado State Leads Nasa Cloudsat Satellite Mission to Launch World’s Most Advanced Weather Radar to Improve Forecasting, Climate Models

A Colorado State University researcher is leading a more than $100 million NASA-funded satellite project that will improve weather and climate prediction and develop critical new space technologies. The CloudSat project, a NASA Earth System Science Pathfinder Mission, will launch into orbit the world’s most advanced weather radar designed to measure properties of clouds that are essential for accurate understanding of Earth’s weather and climate processes.

"CloudSat will provide the first global measurements of cloud thickness, height, water and ice content and a wide range of precipitation data linked to cloud development," said principal investigator Graeme Stephens of Colorado State’s Department of Atmospheric Science. "These measurements will improve weather forecasting and advance understanding of key climate processes."

According to a paper published in the current Bulletin of the American Meteorological Society, or BAMS, CloudSat’s measurements are necessary to improve the way clouds are represented in models used for weather forecasts and climate prediction. The vertical profiles of global cloud properties provided by CloudSat will fill a critical gap in understanding how clouds affect climate and uncover new knowledge about clouds and precipitation and the connection of clouds to the large-scale motions of the atmosphere.

"Clouds are a very important part of Earth’s weather and climate, and the lack of understanding of cloud feedback is widely acknowledged in the scientific community to be a major obstacle confronting credible prediction of climate change," said co-principal investigator Deborah Vane of the Jet Propulsion Laboratory in Pasadena, Calif. "Despite the fundamental role of clouds in climate and weather, there is much that we do not know. The CloudSat mission aims to provide observations necessary to greatly advance understanding of these climate issues."

CloudSat will help researchers in numerous scientific disciplines to:

  • Better understand climate processes: CloudSat data will support new, detailed investigations of how clouds determine the Earth’s energy balance.
  • Improve weather forecasts: CloudSat will improve weather prediction models by measuring cloud properties from the top of the atmosphere to the surface of the Earth, filling a gap in existing and planned space observational systems.
  • Enhance natural hazard mitigation: CloudSat will penetrate into and through thick cloud systems, providing new information to increase the accuracy of severe storm, hurricane and flood warnings.
  • Improve water resource management: CloudSat will link climate conditions to hydrological processes that affect occurrences of drought, incidences of severe weather and availability of water.
  • Develop advanced technology: the CloudSat mission is spurring innovative technology including high-power radar sources, methods of radar signal transmission within spacecraft and integrated geophysical retrieval algorithms.

A unique component of the mission design is that the CloudSat spacecraft will fly in orbital formation as part of a constellation of satellites, including NASA’s Aqua and Aura satellites, the French Space Agency (CNES) PARASOL satellite and the NASA-CNES CALIPSO satellite. This will be the first time that five research satellites will fly together in formation. CloudSat’s radar measurements will overlap those of the other satellites in the constellation. The precision of this overlap creates a unique multi-satellite observing system for studying the atmospheric processes essential to the Earth’s hydrological cycle and weather systems and will provide unsurpassed information about the role of clouds in weather and climate.

The collaborative mission draws on the expertise of industries, universities and laboratories in the United States, Canada, Japan and Europe. The CloudSat satellite will use the first-ever space-borne millimeter wavelength cloud profiling radar, developed for NASA by JPL in partnership with the Canadian Space Agency. This highly advanced radar has the ability to measure both the altitude and the physical properties of clouds. Existing space-based systems can observe only the uppermost layer of clouds and cannot reliably detect the presence of multiple cloud layers or determine the cloud water and ice content.

CloudSat was conceived and proposed by Stephens at Colorado State and is one of the largest research projects in the atmospheric sciences ever led by a university principal investigator. The mission is managed and implemented by JPL for NASA’s Earth Explorers Program Office at the Goddard Space Flight Center. Ball Aerospace of Boulder, Colo., is building the spacecraft that will be launched in 2004 from California’s Vandenberg Air Force Base on the same Delta rocket with the CALIPSO spacecraft.

The U.S. Air Force will operate the CloudSat spacecraft in orbit and will deliver the raw data to the Cooperative Institute for Research in the Atmosphere, or CIRA, located at Colorado State. CIRA will process all CloudSat data and deliver data products to the scientific community. CloudSat data also will be distributed to civilian and military weather forecast agencies.

The U.S. Department of Energy will provide independent verification of the radar performance through its Atmospheric Radiation Measurement Program. Scientists from the United States, Germany, France, Canada and Japan are contributing their facilities and expertise to develop science data products, analyze data and complement the DOE on-orbit verification efforts.

The CloudSat mission is designed for a two-year lifetime to observe more than one seasonal cycle. However, there is no anticipated technical reason why the mission could not last longer as the radar is expected to operate for a minimum of three years.

The paper, "The CloudSat Mission and The A-Train," is available on BAMS’ Web site at Stephens’ painting depicting CloudSat in orbit, "The Useful Pursuit of Shadows," is featured on the bulletin’s cover. More information about the CloudSat project is available on the Web at