Mid-latitude Cirrus Cloud Experiment Underway

Published: 15 May 2004

In late April, scientific collaborators at the National Aeronautics and Space Administration (NASA) carried out two high-altitude flights over the ARM Climate Research Facility Southern Great Plains (SGP) central facility. The purpose of these flights was to use a new suite of cloud property probes on the WB-57F aircraft to more accurately characterize the properties of mid-latitude cirrus clouds—which are composed solely of ice crystals—than has previously been possible. Eight flights over the SGP central facility were originally planned, but the expected cirrus clouds materialized on only two occasions during the flight schedule.

Researchers will use coincident soundings from SGP ground-based instrumentation to compare the following measurements from the WB-57F instrumentation: cirrus cloud particle distribution; ice crystal particle habit; ice-water content; volume extinction coefficient; and water vapor at upper-tropospheric temperatures. These data are necessary to validate and improve existing and emerging algorithms used to derive the microphysical properties of cirrus cloud systems from radiance and reflectivity measurements obtained using satellite-based remote sensing instruments launched (or scheduled to be launched) by NASA and ground-based remote sensors at the ARM Climate Research Facility SGP locale.

The suite of satellite-borne sensors have the capacity to advance our understanding of the coupling between various components of the hydrologic cycle and atmospheric circulation, and hold the additional potential of leading to significant improvements in the characterization of cloud feedbacks in global climate models. Ground-based observations from the ARM Climate Research Facility locales in mid-latitudes, the arctic, and the tropics will play an important role in validating the satellite-based measurements.