The Illumination of Thunderclouds by Lightning: 3. Retrieving Optical Source Altitude

Journal Article · Mon Jan 10 00:00:00 EST 2022 · Earth and Space Science

DOI:https://doi.org/10.1029/2021EA001944· OSTI ID:1839118

Peterson, Michael ^[1]; Light, Tracy E. L. ^[1]; Mach, Douglas ^[2]

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1. ISR‐2 Los Alamos National Laboratory Los Alamos NM USA
2. Science and Technology Institute Universities Space Research Association Huntsville AL USA

Abstract

Optical space‐based lightning sensors such as the Geostationary Lightning Mapper (GLM) detect and geolocate lightning by recording rapid changes in cloud top illumination. While lightning locations can be determined to within a pixel on the GLM imaging array, these instruments are not individually able to natively report lightning altitude. It has previously been shown that thunderclouds are illuminated differently based on the altitude of the optical source. In this study, we examine how altitude information can be extracted from the spatial distributions of GLM energy recorded from each optical pulse. We match GLM “groups” with Lightning Mapping Array (LMA) source data that accurately report the 3‐D positions of coincident Radio‐Frequency (RF) emitters. We then use machine learning methods to predict the mean LMA source altitudes matched to GLM groups using metrics from the optical data that describe the amplitude, breadth, and texture of the group spatial energy distribution. The resulting model can predict the LMA mean source altitude from GLM group data with a median absolute error of <1.5 km, which is sufficient to determine the location of the charge layer where the optical energy originated. This model is able to capture changes to the source altitude distribution in response to convective processes in the thunderstorm, and the GLM predictions can reveal the vertical structure of individual flashes ‐ enabling 3‐D flash geolocation with GLM for the first time. Future work will account for differences in thunderstorm charge/precipitation structures and viewing angle across the GLM Field of View.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: National Aeronautics and Space Administration (NASA); USDOE; USDOE Laboratory Directed Research and Development (LDRD) Program
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 1839118
• Alternate ID(s): OSTI ID: 1839120; OSTI ID: 1999560
• Report Number(s): LA-UR--21-23257; e2021EA001944
• Journal Information: Earth and Space Science, Journal Name: Earth and Space Science Journal Issue: 1 Vol. 9; ISSN 2333-5084
• Publisher: American Geophysical Union (AGU)
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
GLM
GOES
lightning
satellite
thunderstorms