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Using Satellite Observations of Lightning and Precipitation to Diagnose the Behavior of Deep Convection in Tropical Cyclones Traversing the Midlatitudes
  • Lena Heuscher,
  • Patrick Gatlin,
  • Walter A. Petersen
Lena Heuscher
University of Alabama in Huntsville

Corresponding Author:[email protected]

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Patrick Gatlin
NASA Marshall Space Flight Center
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Walter A. Petersen
NASA Marshall Space Flight Center
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Abstract

This study uses a unique combination of geostationary and low-Earth orbiting satellite-based observations of lightning and precipitation, respectively, to examine the evolution of deep convection during the tropical cyclone (TC) lifecycle. The study spans the Atlantic Basin hurricane seasons of 2018-2021 and is unique as it provides the first known analysis of total lightning (intra cloud and cloud to ground) observed in TCs through their extratropical transition and post-tropical cyclone (PTC) phases. We consider the TC lifecycle stage, geographic location (e.g., land, coast, ocean), shear strength, and quadrant relative to the storm motion and environmental shear vectors. Total lightning maxima are found in the forward right quadrant relative to storm motion and downshear of the TC center, consistent with previous studies using mainly cloud-to-ground lightning. Increasing environmental shear focuses the lightning maxima to the downshear right quadrant with respect to the shear vector in tropical storm phases. Vertical profiles of radar reflectivity from the Global Precipitation Measurement mission show that super-electrically active convective precipitation features (>100 flashes) within the PTC phase of TCs have deeper mixed phase depths and higher reflectivity at -10°C than other phases, indicating the presence of more intense convection. Differences in the net convective behavior observed throughout TC evolution manifest in both the TC-scale frequency of lightning-producing cells and the intensity variations of amongst individual convective cells. The combination of continuous lightning observations and precipitation snapshots improves our understanding of convective-scale processes in TCs, especially in PTC phases, as they traverse the tropics and mid-latitudes.
18 Oct 2023Submitted to ESS Open Archive
27 Oct 2023Published in ESS Open Archive