CALIPSO and CloudSat Validation Experiment
(CC-VEx)

The lack of detailed knowledge about cloud processes remains one of the greatest hurdles in improving our understanding of Earth's climate system.

CC-VEx helped overcome these shortcomings by examining the accuracy of unprecedented cloud data provided by NASA's Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) and CloudSat satellites.

Launched in April 2006, CALIPSO/CloudSat measures the vertical structure of clouds and aerosols, tiny airborne particles that influence climate, to provide never-before-seen 3-D perspectives of how clouds and aerosols form, evolve, and affect weather and climate. These data will improve climate and weather computer models and give a better understanding of the human impact on the atmosphere.

CC-VEx employed aircraft with sophisticated sensors and instruments to verify the accuracy of satellite data. The players in this calibration process were the NASA ER-2 high-altitude aircraft - a virtual flying laboratory full of radiometers, radars, and lidar - and a LearJet. The ER-2 is a civilian version of the U-2 reconnaissance aircraft with essentially the same flight properties and can achieve near-space altitudes.

CALIPSO and CloudSat fly in formation with three other satellites to enable an even greater understanding of our climate system from data provided by the broad array of sensors on these spacecraft. CloudSat's Cloud-Profiling Radar is more than 1,000 times more sensitive than typical weather radar and can detect clouds and distinguish between cloud particles and precipitation. It also offers new insights into how fresh water is created from water vapor and how much of this water falls to the Earth's surface as rain and snow. The polarization lidar aboard CALIPSO can detect aerosol particles and distinguish between aerosol and cloud particles. Lidar uses reflected light to determine the characteristics of a target area and each sample produces a 300-feet wide profile of the atmosphere. Profiles collected along an orbit are streamed together to paint a picture of what a vertical slice of our atmosphere looks like.

The data gathered during CC-VEx will help scientists understand how well these satellite instruments are performing and if additional calibrations or corrections are needed. Ultimately, the new information gathered will be fed into mathematical computer models to improve weather and climate predictions.

Mission Website:

http://suborbital.nasa.gov/media/index.html

Contacts:

Chip Trepte
NASA Langley Research Center
Charles.R.Trepte@nasa.gov

Dave Winker
NASA Langley Research Center
David.M.Winker@nasa.gov

Science Objectives:

• Establish calibration algorithms for CALIPSO and CloudSat
• Examine the microphysical properties of clouds, aerosols, and ice
• Determine the reliability of CloudSat ice water content measurements
• Determine the accuracy of CloudSat data in a variety of cloud conditions, especially thick, highly reflective regions
• Verify lidar detection limits over a range of cloud and aerosols types and altitudes

Partners:

A team of nearly 60 personnel, including NASA scientists and pilots worked closely with civilian, university, and Air Force participants.

When:

July 24-August 15, 2006

Where:

Research flights were performed over a wide area in the southeastern United States and western Atlantic, originating at Robins Air Force Base, Georgia.

Links:

For more information about this mission:
http://suborbital.nasa.gov/media/index.html

For more information about CALIPSO:
http://www.nasa.gov/mission_pages/calipso/main/index.html

For more information about CloudSat:
http://www.nasa.gov/mission_pages/cloudsat/main/index.html

For more information about NASA's ER-2 research aircraft:
http://suborbital.nasa.gov/platforms/aircraft/er-2.html

For more information about other related NASA field campaigns:
http://cloud1.arc.nasa.gov/