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Date: 08/08 (Thu)
Time: 14:45-16:30
Place: Cosmo Studio
Speaker: "Shunsuke Niwa"

Title:
"Estimation relationship between Typhoon intensity and lightning electrical properties in the case of Haiyan"

Abstract:
Typhoon cause severe damage in human society every year. In 2013, super typhoon Haiyan attacked Philippines and its damage was comparable to the Great East Earthquake in Japan. So typhoon forecast is very important to deduce the damage caused by typhoon. According to Japan Meteorological Agency (JMA), track forecast for typhoon is improving year by year, but intensity (minimum pressure and maximum sustained wind) forecast have problem.

Lightning is an good indicator of updraft intensity and typhoon intensify by convection in its region so lightning can be used for monitoring typhoon intensity. Previous studies implied lightning can be used for prediction of typhoon intensity. However, all previous studies used only lightning frequency, not electrical properties. Not only lightning frequency but also electrical properties are related to convection in the thundercloud. Therefore using electrical properties of lightning is important to understand relationship between lightning activity and typhoon intensity. I set area r < 200 km (r is distance from the center of Haiyan) for inner core and area 200 km < r < 600 km for rainband. I studied relationship between them for each area using peak current (Ip), Charge moment change (CMC) and charge amount (Q) for typhoon Haiyan as a sample. For this study, I obtained typhoon data from JMA and lightning data from World Wide Lightning Location Network (WWLLN) and Global ELF Observation Network (GEON) to calculate electrical properties.

This study found that Ip and Q were related to convection strength in typhoon region and CMC is related to not only convection strength but also asymmetric structure of typhoon. To investigate whether such like these relationship can be applied for all typhoons or not, I will explore more cases in the future.
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