****************************************************************************************************************

第 244回 大気海洋物理学・気候力学セミナー のおしらせ

日　時： 7月 18日(木) 午前 09:30
場　所： 環境科学院 D棟2階 D201号室

発表者： Var Limpasuvan (School of Coastal and Marine System Science, Coastal Carolina University)
題名：New Tales of the Major Stratospheric Sudden Warming Phenomenon

発表者： 高橋幸弘(大学院理学院・宇宙理学専攻/教授)
\\Yukihiro Takahashi(Graduate School of Science/Professor)
題名：雷放電活動及びOLRの一ヶ月変動
\\Lightning activity and OLR variations with one-month periodicity

****************************************************************************************************************

New Tales of the Major Stratospheric Sudden Warming Phenomenon 
\\(Var Limpasuvan）発表要旨 :
 
The major Stratospheric Sudden Warming (SSW) is a phenomenon in which
the wintertime polar stratosphere undergoes a rapid warming (for an
extended time period) as the circumpolar circulation becomes highly
distorted. Although this phenomenon has been known for over 40 years,
recent observations and advances in numerical simulations have revealed
new findings related to SSW that impacts our understanding of the winter
polar mesosphere/thermosphere, ozone variation, and the interacting
roles of planetary and gravity waves. This presentation highlights our
contributions to these findings and explorations of
SSW's potential global influence.


雷放電活動及びOLRの一ヶ月変動
\\Lightning activity and OLR variations with one-month periodicity
\\(高橋幸弘\\Yukihiro Takahashi）発表要旨 :

It has been recognized in this decade that lightning activity is an
excellent proxy of atmospheric circulation in thunderstorm. GEON, the
global ELF observation network, is the first lightning network covering the
world with globally uniform sensitivity, from which the charge moment
change caused by each lightning stroke is estimated for more than a year.
We show that in the period from February to June 2004 the variation of the
number of lightning strokes in Asia Maritime Continent (hereinafter: MC)
shows one-month oscillation clearly correlated with Outgoing Longwave
Radiation (OLR) in Western Pacific Warm Pool (hereinafter: WPWP) with
amplitudes of few 10s of percent but without apparent phase shift. In other
words, when the thunderstorm activity in MC is enhanced, the OLR in WPWP
becomes large, namely, less cloudy. Moreover, OLR in most part of other
tropical region, especially in central Africa, where the thunderclouds are
the main part of total cloud amount, shows negative correlation with the
number of lightning strokes in MC, implying the activities of thunderstorms
in tropical regions oscillate in the same phase. It was found that such
global oscillation seems to be synchronized with parameters that reflect
solar activity, such as galactic cosmic ray or F10.7 index.

-----
連絡先