ARCUS | Arctic Research Consortium of the United States

6th Annual ARCUS Award for Arctic Research Excellence


Submitted by   Anna Gannet
Authors   Anna Gannet
Category   Physical Science
Title   Arctic Cirrus Microphysical Properties
Affiliation   Program in Atmospheric Science, University of Colorado at Boulder, Boulder, CO, USA

Abstract

High-latitude arctic cirrus clouds were studied using measurements obtained from aboard NASA DC-8 during the SOLVE (SAGE Ill Ozone Loss and Validation Experiment) mission based in Kiruna, Sweden throughout the winter and spring of 1999-2000. The data used in this study were obtained with three instruments: an open-path tunable diode laser hygrometer (RD May and RL Herman, PIs); an FSSP-300 Particle Measurement System (B Anderson, PT), and a closed-path tunable diode laser hygrometer (LM Avallone, PT). The water content was calculated from particle measurements by the FSSP. As expected, the structure of the FSSP observations and the closed-path hygrometer water data were similar, indicating that both are responding to cloud particles. The closed-path tunable diode laser hygrometer typically reported 15-35 ppmv more water than calculated from the FSSP particle data. The excess of particle water seen by the laser hygrometer may be due to larger cirrus cloud ice crystals unaccounted for by the FSSP instrument, since it has an upper-limit of detection at 20 µm for particle diameter. Evidence supporting this theory, including an analysis of the Lidar Atmospheric Sensing instrument (E.V. Browell, PT), will be presented.