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Title: A case study of microphysical structures and hydrometeor phase in convection using radar Doppler spectra at Darwin, Australia

To understand the microphysical processes that impact diabatic heating and cloud lifetimes in convection, we need to characterize the spatial distribution of supercooled liquid water. To address this observational challenge, ground-based vertically pointing active sensors at the Darwin Atmospheric Radiation Measurement site are used to classify cloud phase within a deep convective cloud. The cloud cannot be fully observed by a lidar due to signal attenuation. Therefore, we developed an objective method for identifying hydrometeor classes, including mixed-phase conditions, using k-means clustering on parameters that describe the shape of the Doppler spectra from vertically pointing Ka-band cloud radar. Furthermore, this approach shows that multiple, overlapping mixed-phase layers exist within the cloud, rather than a single region of supercooled liquid. Diffusional growth calculations show that the conditions for the Wegener-Bergeron-Findeisen process exist within one of these mixed-phase microstructures.
Authors:
ORCiD logo [1] ; ORCiD logo [1] ;  [2] ; ORCiD logo [3] ; ORCiD logo [4]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. NASA Langley Research Center, Hampton, VA (United States)
  4. Univ. of Washington, Seattle, WA (United States)
Publication Date:
Report Number(s):
BNL-114428-2017-JA
Journal ID: ISSN 0094-8276; R&D Project: 2019‐BNL-EE630EECA-Budg; KP1701000; TRN: US1702870
Grant/Contract Number:
SC0012704; AC05-76RL01830
Type:
Accepted Manuscript
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 44; Journal Issue: 14; Journal ID: ISSN 0094-8276
Publisher:
American Geophysical Union
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; supercooled liquid; cloud phase; convection; Darwin Australia; radar Doppler spectra; k-means clustering
OSTI Identifier:
1402422
Alternate Identifier(s):
OSTI ID: 1375069