HR: 1330h
AN: A22A-1044    [PDF]
TI: Measurements of Ice Water Content in Low-latitude Cirrus Clouds
AU: * Avallone, L M
EM: avallone@lasp.colorado.edu
AF: Laboratory for Atmospheric and Space Physics, University of Colorado 590 UCB, Boulder, CO 80309-0590 United States
AU: Hallar, A G
EM: hallar@lasp.colorado.edu
AF: Laboratory for Atmospheric and Space Physics, University of Colorado 590 UCB, Boulder, CO 80309-0590 United States
AB: During the CRYSTAL-FACE campaign, ice water content (IWC) was determined on the basis of observations of so-called total water made with a closed-path tunable diode laser hygrometer (CLH). The instrument was configured especially for measurements of thin cirrus, by employing a forward-facing subisokinetic inlet that inertially enhances articulate concentrations by about a factor of 50. The resulting detection limit for IWC is better than 0.05 mg m$^{-3}$ under most conditions. In this presentation, we will describe the CLH instrument performance, illustrate the procedure for determining IWC from the total water observations and discuss the uncertainties in the resulting IWC values. We will show several examples covering the wide range of cirrus IWC observed, from $<$ 0.1 mg m$^{-3}$ to $>$ 1 g m$^{-3}$, with particular emphasis on the morphology of clouds found near the tropopause.
DE: 0320 Cloud physics and chemistry
DE: 0365 Troposphere--composition and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting