CloudSat

NASA deployed CloudSat and its companion spacecraft CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) to investigate how clouds and aerosols affect weather, climate and the quality of air on Earth. From Vandenberg Air Force Base in California, a Boeing Delta II rocket deployed CloudSat on April 28, 2006. The CloudSat mission runs in cooperation with the Canadian Space Agency.
 
CloudSat began as part of NASA's Earth System Science Pathfinder program in 1999. Overall management of the mission belongs to NASA's Jet Propulsion Laboratory (JPL). Professor Graeme Stephens of Colorado State University and the CloudSat Science Team lead the scientific efforts.
 
Currently in orbit 438 miles above Earth, CloudSat is part of an interesting orbital formation nicknamed the "A-Train." The three other Earth-observing satellites that comprise the A-Train include Aqua, Aura and Centre National d'Etudes Spatiales' (CNES) PARASOL. Together, these satellites contribute to our further knowledge of Earth's climate.

CloudSat Radar

The difference between CloudSat and other satellites studying clouds is that CloudSat uses an advanced radar system to "slice" though clouds, according to NASA. This unique ability enables scientists to study the entire structure and formation of clouds. In essence, CloudSat produces 3-D images rather than flat images. Other satellites are only able to view the top layers of clouds.
 
Even though CloudSat's initial mission is just under two years, its radar is expected to last up to three years. The 22-month span allows for more than one seasonal cycle to be recorded by CloudSat. CALIPSO will operate for three years.

CloudSat's Mission

The observations that CloudSat and CALIPSO make will compose the first complete profile of the physical properties of clouds and aerosols (particles of liquids or solids suspended in gas). The CloudSat mission includes seasonal and geographic variations.

The data gathered by CloudSat will determine how clouds and aerosols are measured in the future and how they impact current global models. In the end, these models should improve weather forecasts. The impact of improved weather predictions will ultimately help us improve our management of water, air quality, natural disasters and even aviation safety.

CloudSat's objectives include:

  • evaluating existing cloud models and cloud processes
  • evaluating the observations of clouds made by other satellites, including Aqua and CALIPSO
  • examining how aerosols indirectly affect clouds
  • examining the relationship between the water and ice content of clouds and heating of both the Earth's surface and its atmosphere by different cloud systems.
The main instrument behind CloudSat is the Cloud Profiling Radar (CPR). Developed by NASA and the Canadian Space Agency, this radar was designed specifically to meet CloudSat's objectives. CloudSat's CPR is over 1,000 times more sensitive than standard weather radars, according to NASA. It is so precise that it can determine the difference between cloud particles and actual precipitation.

CloudSat's Contributions

Once CloudSat records a cloud image, it must travel an average of four hours in orbit before it reaches the vicinity of a large, ground-based antenna that retrieves its data. A base in Albuquerque, N.M., collects the data over the course of the day. When an entire day's worth of data has been collected, the base sends the data to Colorado State University. CloudSat will deliver roughly 12 terabytes (or a trillion bits) of information to Earth during its 22-month mission.

CloudSat's work has continually provided us with important details on climate change. For instance, in 2007 images of polar clouds helped illustrate the effect of cloud cover over the western Arctic region. The National Center for Atmospheric Research in Boulder, Colo., showed that total cloud cover over this region was 16 percent less than in 2006, which resulted in clearer skies for 2007.

These clear skies heated the surface enough to raise ocean temperatures and melt sea ice. As a result, CloudSat's observations affirmed the effect of the variability of weather patterns on the Arctic environment.
 
Resources
 
Colorado State University (2008). CloudSat: Overview. Retrieved February 9, 2008, from the Colorado State University Department of Atmospheric Science Web site.
 
Earth Today (2007). Cloudsat, World's Most Sensitive Cloud-profiling Radar in Orbit Celebrates One Year Above Earth. Retrieved February 8, 2008, from the EarthToday.net Web site.
 
NASA (2008). CloudSat. Retrieved February 8, 2008, from the Science@NASA Web site.
 
NASA (2008). CloudSat: Revealing the Inner Secrets of Clouds. Retrieved February 7, 2008, from the NASA Web site.