Spectral Latent Heating Retrieval for the Midlatitudes Using GPM DPR. Part II: Development and Consistency Check of the Retrieval Algorithm

Abstract A new algorithm for estimating the latent heating profile for precipitation in the extratropics was developed to extend the current spectral latent heating (SLH) algorithm that applies only to the tropics. The new algorithm incorporates normalized relative height into the heating estimation for deep stratiform precipitation. The normalized relative height successfully determines the cloud-base heights, above and below which latent heating and cooling occur, from the precipitation profile and adapts well to quite diverse precipitation and related heating in the extratropics. Another important improvement is the detection of multiple precipitation layers in the precipitation profiles that are not implemented in the algorithm for the tropics, further ensuring a reasonable estimation of the heating profile for diverse precipitation in the extratropics. The retrieval algorithm was evaluated from several perspectives. A self-consistency check using the numerical simulation data to construct the lookup tables confirmed that our algorithm can reproduce the true heating profiles well. Application to Global Precipitation Measurement (GPM) Ku-band precipitation radar (KuPR)-measured precipitation further confirmed that our algorithm works well, especially in capturing the variability of cloud-base heights for deep stratiform precipitation. A zonal-mean meridional cross section of the heating, including both tropics and extratropics up to 65° latitude, is described for the first time for the SLH product. The estimated distribution of heating in the extratropics corresponds well to midlatitude storm-track activity.