Microphysical and Thermodynamic Retrievals in Deep Convective Clouds Using Polarimetric Radar Measurements and Spectral Cloud Models with Explicit Treatment of Aerosol Impact on Convective Processes

Principal Investigator(s):
Alexander Ryzhkov, University of Oklahoma

The proposed research will be focused on the improvement of microphysical treatment of convective updrafts and cold pools in the cloud models of mixed-phase deep convective clouds. This implies the development of novel methods for microphysical and thermodynamic retrievals using polarimetric radar measurements and cloud models with spectral microphysics. Microphysical retrievals will include advanced schemes for estimation of mass fluxes and mixing ratios of hydrometeors with different habits in the mixed-phase deep convective clouds. Thermodynamic retrievals will involve radar estimation of latent heat rates with an emphasis on heating rates caused by condensation in convective updrafts and cooling rates due to evaporation and melting of hydrometeors which lead to development of cold pools. The sensitivity of the microphysical and thermodynamic parameters of convective clouds to aerosols will be examined with the Hebrew University of Jerusalem cloud model (HUCM) which explicitly treats the aerosol impact on microphysical and thermodynamic processes within the cloud.

Large polarimetric radar datasets collected during the MC3E field campaign and complemented by the data from various ARM remote sensing instruments and aircraft in situ observations will be used for optimization of the spectral cloud models using the forward polarimetric radar operator via comparison of the polarimetric model output and direct radar observations.

Three major research objectives will be addressed in the proposed study.

  1. Developing novel techniques for microphysical and thermodynamic retrievals in convective storms using polarimetric radar data.
  2. Investigating the impact of aerosol processes on the properties of convective systems using advanced cloud models with spectral microphysics and polarimetric radar observations.
  3. Examining multifrequency polarimetric ARM radar data to improve microphysical parametrizations in the models, develop new radar retrieval methodologies, and validate their efficiency.

The proposed study will enhance our knowledge of microphysics of deep convective clouds which is crucially important for better understanding of large-scale processes and their reproduction in global circulation models. As a result of this study, an upgraded version of the WRF model with improved spectral microphysics package will be developed as well as methodologies for microphysical and thermodynamic retrievals using polarimetric radar data which can be used for improvement of bulk microphysical parametrization in large-scale models.