Monday, 7 January 2019
Hall 4 (Phoenix Convention Center - West and North Buildings)
In this study, we retrieved total liquid water path (TLWP), including both rain liquid water path (RLWP) and cloud liquid water (CLWP) in stratiform precipitation systems. The retrieval methods use the measurements from the vertically pointing radars (VPRs) at 35 GHz and 3 GHz operated by the U.S Department of Energy Atmospheric Radiation Measurement (ARM) and National Oceanic and Atmospheric Administration (NOAA) during the field campaign Midlatitude Continental Convective Clouds Experiment (MC3E). The measured radar reflectivity and mean Doppler velocity from both VPRs and spectrum variance from the 35 GHz radar are utilized. With the aid of the cloud base detected by ceilometer, the liquid layer TLWP is retrieved under two different situations: (I) the cloud base is higher than the melting base, and (II) the cloud base is lower than the melting base. Under the situation I, the TLWP is primarily contributed by raindrops only, i.e., RLWP, which is estimated by analyzing the Doppler velocity differences between two VPRs. For the situation II, cloud droplets and raindrops are co-existed in the liquid layer. The CLWP is estimated using an attenuation-based algorithm and RLWP is estimated using parameterizations derived from radar reflectivity and RLWC retrievals near the surface layer. Preliminary results from the four selected cases during MC3E show that the mean value of CLWP can be up to ~0.8 kg m-2 and is much larger than RLWP (~0.3 kg m-2). The retrieved CLWP and RLWP in the stratiform precipitation systems will be useful to understand different cloud-precipitation processes, such as condensation, evaporation, autoconversion and accretion etc. Furthermore, independent cloud and precipitation retrieval data can provide invaluable data source for investigating the cloud-precipitation transition processes and shed light on improving the model simulations in the future.
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