Start
October 30, 2020 - 3:00 pm
End
October 30, 2020 - 4:00 pm
Categories
Convective Meteorology (Mesoscale Dynamics)Convective Meteorology (Mesoscale Dynamics) Seminar
Controls on the Size Distributions of Ice Crystals in High Ice Water Content (HIWC) Regions: Results from Darwin
Peter Brechner
Friday, October 30, 2020
3 pm
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https://meet.google.com/ksh-txvg-kni
Multiple occurrences of high ice water content (HIWC) regions in areas of low reflectivity have been observed over tropical areas, suggesting large concentrations of small ice crystals are present. The causes of these large concentrations of small ice crystals are poorly known. This study uses data collected during the collaborative European High Altitude Ice Crystals – North American HIWC field campaign (HAIC-HIWC) based out of Darwin, Australia in 2014 to investigate the nature of ice crystal size distributions in these HIWC regions containing enhanced concentrations of small ice crystals. An isokinetic evaporator probe (IKP) measuring the total ice water content, and a two-dimensional stereo probe (2D-S) and a precipitation imaging probe (PIP) measuring the size distribution of ice crystals were installed on the French Falcon aircraft during HAIC/HIWC. Unimodal gamma distributions were fit to the observed 5-second averaged number distribution functions. The characteristics of the size distributions (e.g., median mass diameter, gamma fit parameters, etc.) were determined as a function of environmental conditions such as temperature and ice water content. Implications of these results for the representation of size distributions in models are discussed.