edu.ucar.opensky::articles:25458 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-24T22:47:26.617049 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7g44v15 Coalescence and secondary ice development in cumulus congestus clouds 2022-04-01T00:00:00Z publication https://n2t.org/ark:/85065/d7g44v15 https://doi.org/10.1175/JAS-D-21-0188.1 Lawson, R. P. author Bruintjes, Roelof T. author Woods, S. author Gurganus, C. author UCAR/NCAR - Library publisher Understanding ice development in cumulus congestus (CuCg) clouds, which are ubiquitous globally, is critical for improving our knowledge of cloud physics, precipitation and climate prediction models. Results presented here are representative of data collected in 1008 penetrations of moderate to strong updrafts in CuCg clouds by five research aircraft in six geographic locations. The results show that CuCg with warm (similar to 23 degrees C) cloud-base temperatures, such as in tropical marine environments, experience a strong collision- coalescence process. Development of coalescence is also correlated with drop effective radius >similar to 12 to 14 mm in diameter. Increasing the cloud- base drop concentration with diameters from 15 to 35 mm and decreasing the drop concentration, 15 mm appears to enhance coalescence. While the boundary layer aerosol population is not a determinate factor in development of coalescence in most tropical marine environments, its impact on coalescence is not yet fully determined. Some supercooled large drops generated via coalescence fracture when freezing, producing a secondary ice process ( SIP) with production of copious small ice particles that naturally seed the cloud. The SIP produces an avalanche effect, freezing the majority of supercooled liquid water before fresh updrafts reach the -16 degrees C level. Conversely, CuCg with cloud-base temperatures <= similar to 8 degrees C develop significant concentrations of ice particles at colder temperatures, so that small supercooled water drops are lofted to higher elevations before freezing. Recirculation of ice in downdrafts at the edges of updrafts appears to be the primary mechanism for development of precipitation in CuCg with colder cloud-base temperatures. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright 2022 American Meteorological Society None eng geoscientificInformation