Mission Name CRYSTAL-FACE Download CRYSTAL-FACE poster (132 kb) posterRegion LASP Instruments CLH: Closed-path Tunable Diode Laser Hygrometer Destination Earth's atmosphere from 30000 - 60000 feet where cirrus clouds form Launch Date N/A: Multiple experments performed during July 2002 from a WB-57F aircraft Launch Location Experiments took place over the southern tip of Florida (WB-57F aircraft based at Key West Naval Air Station) Launch Vehicle NASA's WB-57F aircraft Mission Duration May-July 2002 Mission Description/ LASP involvement CRYSTAL-FACE is a measurement campaign designed to investigate tropical cirrus cloud physical properties and formation processes. Understanding the production of upper tropospheric cirrus clouds is essential for the successful modeling of the Earth’s climate. LASP Divisions Involved Engineering * Science LASP Mission Web Page None Official Mission Web Page http://cloud1.arc.nasa.gov/crystalface/

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The Science and Goal

Understanding the interaction of clouds with solar and terrestrial radiation is an important research goal, in light of the significance of clouds in the Earth's energy balance and the possibility that cloud properties will change as climate changes. Accurate knowledge of the amount of water condensed in clouds - ice water content (IWC) and ice water path (IWP) - is important for retrieving cloud parameters from space-borne instruments, and for modeling the radiative properties of clouds.

Typical convective and cirrus anvil clouds sampled during CRYSTAL-FACE. This picture was taken from the cockpit of a WB-57 aircraft.

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LASP Involvement (More)

Engineering:

LASP engineers built the CLH instrument for CRYSTAL-FACE.

• CLH: Closed-path Tunable Diode Laser Hygrometer
  Principal Investigor, Linnea Avallone, and her research group developed a technique for determining the water content of particles in cirrus clouds. A closed-path tunable diode laser hygrometer (CLH) is coupled to a heated, sub-isokinetic inlet to measure the amount of water condensed in particles with diameters larger than about 4 micrometers. Although smaller particles are also sampled, the instrument's sensitivity to them is low. These measurements are used, along with observations of water vapor made by a similar instrument operated by the Jet Propulsion Laboratory, to understand the fraction of water present in the condensed phase in a variety of cirrus cloud types.

Science:

LASP participated in the NASA CRYSTAL-FACE campaign, making measurements of particulate water from the NASA WB-57F aircraft in a variety of cirrus: thunderstorm anvils, aircraft contrails, and so-called subvisual cirrus. The instrument has demonstrated a remarkable sensitivity, with a detection limit of less than 0.1 mg of condensed water per cubic meter of air. We are using the observations obtained during CRYSTAL-FACE to gain a better understanding of the relationships among cloud IWC, particle sizes, and cloud radiative properties. To further these studies, LASP participated in NASA's Midlatitude Cirrus Experiment (MidCiX) in April/May 2004, focusing on direct comparisons of in situ and remote measurements of midlatitude cirrus clouds.

 

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