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Climatology and Detection of Overshooting Convection From 4 Years of GPM...

Liu, C., C. Liu, and L. Hayden (2020), Climatology and Detection of Overshooting Convection From 4 Years of GPM Precipitation Radar and Passive Microwave Observations, J. Geophys. Res., 125, e2019JD032003, doi:10.1029/2019JD032003.
Abstract: 

A 4‐year Global Precipitation Measurement (GPM) Precipitation Feature (PF) data set is used to quantify the frequency and global distribution of overshooting convection. In this study, overshooting convection is defined as PFs with maximum 20 dBZ echo top height (MAXHT20) greater than the height of the lapse rate tropopause, derived from ERA‐Interim reanalysis data. The geographical distribution of overshooting convection exhibits a strong preference for specific land regions, such as over the central United States, Argentina, Central Africa, and Colombia. Larger areas and greater occurrence of 20 dBZ radar reflectivity at the tropopause are found in northern middle to high latitudes than in the tropics. The occurrence of 20 dBZ radar reflectivity reaching above the level of 380 K potential temperature (Z380K) in middle and high latitudes is found to be comparable to that in the tropics. Furthermore, a methodology is developed to detect overshooting convection using the GPM Microwave Imager measured brightness temperature at 183.31 ± 3 and 183.31 ± 7 GHz, and Polarization Corrected Temperature at 89 GHz. The geographical distribution of overshooting convection can be closely reproduced using the combinations of these brightness temperatures with an average Heidke skill score of 0.4 and probability of 0.38. This shows the possibility of identifying overshooting convection from microwave observations at high‐frequency channels near the water vapor absorption line centered at 183.31 GHz from other satellite missions.

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Research Program: 
Atmospheric Composition Modeling and Analysis Program (ACMAP)
Atmospheric Dynamics and Precipitation Program (ADP)
Mission: 
DCOTSS