presented by Jeffrey Stith (EOL/RAF)
The results from several recent studies of the microphysical and kinematic structure of updrafts and downdrafts in convective storms in the Amazon and at Kwajalein, Marshall Islands, will be presented. The studies are based on in situ airborne measurements of the cloud particles and updraft speed. These will be compared with similar measurements made from convective storms during two field projects in North Dakota. Remarkably similar particle types and concentrations were found in the two tropical locations when updrafts at similar temperatures were examined. Examination of the updraft structures in these clouds reveals that they are also quite similar. The tropical clouds contained chain aggregate ice particles, which may be due to electrical forces in the clouds, and high concentrations of small quasi-spherical ice particles at relatively warm temperatures. Most liquid water was confined to the mid to lower levels of the tropical clouds and decreased at midlevels, although small amounts of liquid water were found at much colder temperatures. In contrast, liquid water from the North Dakota storms increased at cloud midlevels. Midlevel tropical updrafts almost always contain precipitation, while some updrafts at midlevels in the North Dakota clouds were free of precipitation. The highest concentrations of cloud droplets in the North Dakota clouds were observed at cloud midlevels, not near the cloud base, suggesting the formation of new droplets well above the cloud base.
Seminar is from 2:00pm to 3:00pm in FL2 Room 1022
on Tuesday, February 22, 2005.
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