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Comparing Tropopause-Penetrating Convection Identifications Derived From NEXRAD...

Cooney, J., K. M. Bedka, K. P. Bowman, K. V. Khlopenkov, and K. Itterly (2021), Comparing Tropopause-Penetrating Convection Identifications Derived From NEXRAD and GOES Over the Contiguous United States, J. Geophys. Res..

Overshooting tops (OTs) are a well-known indicator of updrafts capable of transporting air from the troposphere to the stratosphere and generating hazardous weather conditions. Satellites and radars have long been used to identify OTs, but the results have not been entirely consistent due to differences in sensor and measurement characteristics. OT detection approaches based on satellite infrared (IR) imagery have often been validated using human-expert OT identifications, but such datasets are time-consuming to compile over broad geographic regions. Despite radar limitations to detect the true physical cloud top, OTs identified within multi-radar composites can serve as a stable reference for comprehensive satellite OT analysis and detection validation. This study analyzes a large OT data set compiled from Geostationary Operational Environmental Satellites (GOES)-13/16 geostationary IR data and gridded volumetric Next-Generation Radar (NEXRAD) reflectivity to better understand radar and IR observations of OTs, quantify agreement between satellite and radar OT detections, and demonstrate how an increased spatial sampling from GOES-13 to GOES-16 impacts OT appearance and detection (∼60%) is ∼15% lower than GOES-16 (∼75%), which is mostly attributed to coarser spatial resolution. performance. For nearly time-matched scenes and moderate OT probability, the GOES-13 detection rate NEXRAD column-maximum reflectivity and tropopause-relative echo-top height as a function of GOES OT probability were quite consistent between the two satellites however, indicating that efforts to account for differing resolution were largely successful. GOES false detections are unavoidable because outflow from nearby or recently decayed OTs can be substantially colder than the tropopause and look like an OT to an automated algorithm.

Funding Sources: 
Funding for this work was provided by the National Science Foundation through grants AGS-1522906 and AGS-1522910 to Texas A&M University and the University of Oklahoma, respectively, the NASA ROSES award 18-DISASTER18-0008, and support from the NASA Earth Venture Suborbital DCOTSS mission. John Cooney's research was supported by an appointment to the NASA Postdoctoral Program at NASA Langley Research Center, administered by University Space Research Association under contract with NASA.