Lightning Distance Estimation Using LF Lightning Radio Signals via Analytical and Machine-Learned Models
Year: 2020
Type: article
Institution: University of Colorado Boulder
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: closed
Awards: THUNDERSTORMS ARE A SIGNIFICANT HAZARD TO PUBLIC SAFETY AND PROPERTY DAMAGES DUE TO THEIR ASSOCIATION WITH SEVERE WEATHER PHENOMENA E.G. INTENSE LIGHTNING AND STRONG WINDS. THE THUNDERSTORM PROCESSES DRIVING THE EVOLUTION OF SEVERE WEATHER ARE NOT WELL UNDERSTOOD INCLUDING PROCESSES THAT CONTROL STORM ELECTRIFICATION AND LIGHTNING PRODUCTION AND HOW THESE IN TURN AFFECT PRODUCTION OF OTHER SEVERE WEATHER. IN THE PAST TWO DECADES HOWEVER THE DISCOVERY OF DISTINCT TYPES OF ENERGETIC INTRA-CLOUD (IC) DISCHARGES OPENED A NEW PATH FOR THE STUDY OF ASSOCIATED ENERGETIC PHENOMENA INSIDE THUNDERSTORMS AND THE CONTROL PROCESSES THAT GOVERN THEM. LIGHTNING DICHARGES GENERATE RADIO SIGNALS (SFERICS) ALONG WITH THE BURST OF ENERGETIC RADIATION RELEASED WHICH CAN THEN BE USED TO DETERMINE PROPERTIES OF THE GENERATING DISCHARGE. THOUGH MOST PREVIOUS RESEARCH USING SFERICS FOCUSED ON CLOUD-TO-GROUND FLASHES (CGS) MORE RECENTLY ENERGETIC IC DISCHARGES HAVE BEEN SHOWN TO BE ASSOCIATED WITH OTHER LIGHTNING PHENOMENA BOTH IN AND ABOVE THE ATMOSPHERE AND ARE THUS IMPORTANT IN PROVIDING A BETTER UNDERSTANDING OF THUNDERSTORMS. WE ARE PARTICULARLY INTERESTED IN TWO ENERGETIC IC DISCHARGES: COMPACT INTRA-CLOUD LIGHTNING DISCHARGES (CIDS) WHICH ARE ISOLATED WITH VERY SHORT PULSE AND RISE TIMES; AND ENERGETIC INTRA-CLOUD PULSES (EIPS) WHICH HAVE SLOWER PULSE TIMES ARE FOLLOWED BY SMALLER DISCRETE PULSES AND HAVE BEEN RECENTLY ASSOCIATED WITH TERRESTRIAL GAMMA RAY FLASHES (TGFS). BOTH OF THESE EVENTS PRODUCE INTENSE RF RADIATION IMPLYING EXTREMELY LARGE CURRENTS INSIDE THE CLOUD. THUS WE EMPHASIZE THE NEED FOR FURTHER IDENTIFICATION OF CIDS AND EIPS. ADDITIONAL STUDY ON THE GENERATING MECHANISMS OF THESE EVENTS WILL ALLOW A BETTER UNDERSTANDING ON THE PHYSICAL PROCESSES GOVERNING THE DYNAMICS OF THUNDERSTORMS AND STUDY OF EIPS WILL FURTHER HELP IN IDENTIFYING TGFS. TGFS MIGHT EVENTUALLY BE DETECTED SOLELY FROM GROUND-BASED SOURCES THROUGH RADIO SIGNATURE PROXIES ENABLING RESEARCH INTO TGF-GENERATING PROCESSES AND PREDICTION OF TGF OCCURRENCE PROBABILITY. IN THE PROPOSED PROJECT WE WILL MEASURE THE PREVALENCE OF THESE INTENSE IC DISCHARGE TYPES AND THEIR ASSOCIATION WITH OTHER ENERGETIC PHENOMENA THUS IMPROVING OUR UNDERSTANDING OF SEVERE WEATHER EVOLUTION AND OUR CAPABILITY TO PREDICT EXTREME WEATHER EVENTS THROUGH RADIO SIGNATURES OF LIGHTNING. THE SOCIETAL BENEFITS APPLY DIRECTLY TO NASA'S 2014 STRATEGIC PLAN OBJECTIVE 2.2: ADVANCE KNOWLEDGE OF EARTH AS A SYSTEM TO MEET THE CHALLENGES OF ENVIRONMENTAL CHANGE AND TO IMPROVE LIFE ON OUR PLANET . WE WILL ALSO ACQUIRE ENERGETIC LIGHTNING DATA FOR FUTURE RESEARCH IN THIS FIELD HELPING FULFILL NASA'S 2007 EARTH SCIENCE DECADAL SURVEY RECOMMENDATION FOR SUSTAINING AND ENHANCING SURFACE-BASED SOUNDING NETWORKS NECESSARY TO SATISFY CLIMATE EARTH SCIENCE AND WEATHER FORECASTING NEEDS. IN ORDER TO ACCOMPLISH OUR SCIENTIFIC GOALS WE WILL USE DATA FROM I) THE GEOSTATIONARY LIGHTNING MAPPER (GLM) INFRARED CAMERA ON BOARD THE GOES-R SATELLITE; II) SFERIC DATA FROM OUR OWN LF (3-300 KHZ) MAGNETIC RECEIVERS TO BE INSTALLED IN CO UT PUERTO RICO AND ARGENTINA; III) NATIONAL LIGHTNING DETECTION NETWORK (NLDN) FLASH EVENTS DATA; AND IV) TGF EVENT DATA FROM GAMMA-RAY SPACE TELESCOPES RHESSI AND FERMI. FIRST WE WILL ASSEMBLE A DATASET OF EVENTS DETECTED BY GLM OF ONLY IC FLASHES BY REMOVING KNOWN CG FLASHES FROM NLDN DATA AND USE CORRESPONDING LF DATA TO CHARACTERIZE THE GLM CLUSTERING ALGORITHM. NEXT WE WILL REQUEST LOWER LEVEL IMAGE DATA PRODUCTS FROM GLM TO DEVELOP A METHOD VIA MACHINE LEARNING TECHNIQUES SUCH AS NEURAL NETWORKS FOR CLASSIFICATION OF ENERGETIC IC DISCHARGES IN GLM DATA. WITH THIS METHOD WE CAN THEN SAMPLE GLM IMAGE DATA TO FIND THE PREVALENCE OF DISTINCT ENERGETIC IC DISCHARGE TYPES. FINALLY WE CAN ANALYZE THE CONNECTION BETWEEN IC DISCHARGES ESPECIALLY EIPS AND TGFS BY USING DATA FROM THE RHESSI AND FERMI MISSIONS COINCIDENT WITH GLM DATA AND LF DATA., G673832657
OpenAlex ID: W3008419670