HR: 1340h
AN: AE33A-0187    [Abstracts]
TI: The Contrast of the El Ni\~{n}o and La Ni\~{n}a Events on the Convection Over East Asia
AU: * Oita, S
EM: oita@comf5.comm.eng.osaka-u.ac.jp
AF: Osaka University, 2-1 Yamada-oka, Suita, 5650871 Japan
AU: Morimoto, T
EM: morimoto@comf5.comm.eng.osaka-u.ac.jp
AF: Osaka University, 2-1 Yamada-oka, Suita, 5650871 Japan
AU: Kawasaki, Z
EM: zen@comm.eng.osaka-u.ac.jp
AF: Osaka University, 2-1 Yamada-oka, Suita, 5650871 Japan
AU: Ushio, T
EM: ushio@aero.osakafu-u.ac.jp
AF: Osaka Prefecture University, 1-1 Gakuencho, sakai, 5997531 Japan
AB: The 1997-1998 El Ni\~{n}o is one of the strongest El Ni\~{n}o Southern Oscillation (ENSO) events. The 1997-1998 El Ni\~{n}o began to develop in March, 1997 and strengthened rapidly over the next year. After a gradual decline in the intensity of these thermal anomalies in early 1998, the El Ni\~{n}o event abruptly ended during May-June, 1998. After this strongest El Ni\~{n}o event, La Ni\~{n}a event started soon. This La Ni\~{n}a event continued more than a year, and then disappeared in the spring of 2000. {\it Lightning Research Group of Osaka University} (LRG-OU) asserted that the lightning activities are more frequent despite less convective storms during the El Ni\~{n}o period than during La Ni\~{n}a period in East Asia, especially in Indonesia. In this paper, the authors pay their attention to the contrast of the convective activities between El Ni\~{n}o and La Ni\~{n}a periods over the East Asia. The effects of El Ni\~{n}o and La Ni\~{n}a events to the precipitation and lightning activities are investigated. Their possible correlation with some parameters of storms is also considered. The authors studied the convection and lightning activities over the Pacific Ocean and the surrounding Maritime Continent, especially in East Asia, in terms of the Tropical Rainfall Measuring Mission (TRMM) observations. The data of lightning flash and precipitation are obtained from Lightning Imaging Sensor (LIS) and Precipitation Radar (PR) on TRMM, respectively. These PR data include the storm heights, number of observed precipitation, and so on. The increase in number of lightning flashes during El Ni\~{n}o over East Asia has been studied by making a comparison of convective activities between April, 1998, corresponding to El Ni\~{n}o period, and April, 1999, corresponding to El Ni\~{n}o period. The main differences are summarized as follows; 1) During the El Ni\~{n}o/La Ni\~{n}a period the number of lightning flashes increases/decreases. 2) During the El Ni\~{n}o/La Ni\~{n}a period the times of precipitation decreases/increases, but the mean intensity of precipitation is stronger/weaker than Normal period. So the total amount of precipitation is low/high. 3) During the El Ni\~{n}o/La Ni\~{n}a period the storms arise less/more, but the higher storms over 7000m are generated more/less. These results lead to the conclusion that during the La Ni\~{n}a period many storms arise and make a lot of precipitation, but storms do not grow up so high as to make heavy lightning activity. On the contrary, during the El Ni\~{n}o period the storms do not arise so frequently and consequently it does not rain so often. But more storms grow up to high altitude, and those storms increase the lightning flashes. Tough the results in this study are preliminary and further investigation and more evidences are needed, we found the implications of the change in convective precipitation due to El Ni\~{n}o and La Ni\~{n}a events on the lightning activity and their possible correlation with some parameters for storms.
DE: 1724 Ocean sciences
DE: 1600 GLOBAL CHANGE (New category)
DE: 1630 Impact phenomena
DE: 1640 Remote sensing
SC: Atmospheric and Space Electricity [AE]
MN: 2004 AGU Fall Meeting