EOL Seminar - Ice cloud formation from in-situ airborne observations to a hierarchy of models

Tuesday, August 2, 2016 - 15:30 to 16:30
Contact Name: 
Steve Oncley
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Ice cloud formation from in-situ airborne observations to a hierarchy of models

Minghui Diao

San Jose State University

Department of Meteorology

Radiative forcings of water vapor and ice crystals are significantly different, and the conditions of ice supersaturation (ISS, where relative humidity with respect to ice is greater than 100%) hold a crucial pathway for ice crystal formation. Recent observations reported that ISS can frequently occur in both tropical and extratropical UT/LS, under clear-sky and in-cloud conditions. However, it is challenging to represent the microphysical and macrophysical characteristics of ISS in model simulations.

Our analysis will use in-situ airborne observations from eight NSF flight campaigns (2008-2016). Comparisons on ice clouds and ISS characteristics will be shown between in-situ observations and a hierarchy of models: the NCAR CM1 cloud-resolving model, WRF and CAM5.

We found that misrepresenting the in-situ observed ISS as artificial ice crystals leads to the TOA net radiation impacts of 54 (4.24) W/m2 at maximum (average) based on five flight campaigns. Comparisons among in-situ observations, WRF and CM1 simulations will be shown, focusing on the sensitivities to horizontal grid spacings and microphysical parameters. Recent observations from ORCAS campaign (2016) will be compared with CAM5 simulations, to examine the coexistence of supersaturation, ice crystals and liquid droplets. The most recent laboratory calibrations on the NCAR Vertical Cavity Surface Emitting Laser (VCSEL) hygrometer using two EOL environmental chambers will also be shown.

Seminar will be webcast at: http://www.fin.ucar.edu/it/mms/fl2-live.htm‚Äč


Tuesday, 2 August 2016, 3:30 PM

Refreshments 3:15 PM

NCAR-Foothills Laboratory

3450 Mitchell Lane

Bldg 2 Small Seminar Room (Rm1001)