1.6 Physical Processes Leading to Elevated Convection Initiation during 25–26 June PECAN: Convective-Scale Reanalysis Based on a Radar Data Assimilation System

Tuesday, 9 January 2018: 9:45 AM
Room 6A (ACC) (Austin, Texas)
Juanzhen Sun, NCAR, Boulder, CO; and S. B. Trier

In this second part of a two-part study (Trier et al. for the first part), we use VDRAS (Variational Doppler Radar Analysis System) to conduct reanalysis of the 25-26 June elevated CI event. The goal is to gain understanding of the convective-scale processes that could have triggered the rearward initiation of two successive convective lines. VDRAS is a 4DVar-based data assimilation system that combines mesoscale model output, Doppler radar observations, and surface observations to produce detailed 3D structure and evolution (10 min updates) of convective-scale reanalysis. The specific scientific issues that we investigate in this second part study are: 1. Does the cold pool (or gravity waves) produced by precursor convective lines contribute to the initiation of subsequent lines? 2. Are there any other convective-scale processes involved in triggering the rearward initiations? 3.To what extent does the radar data assimilation in VDRAS lead to detection of important fine-scale features in the reanalysis that are not captured in the WRF simulation? Our initial examination of the reanalysis reveals potentially important physical processes that are not clearly evident from an analysis of observations from single data platforms. Detailed analysis of the results will be conducted and presented in the meeting.
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