不過呢,今天最重要的,是.......,我把海綿寶寶帶去氣象局領這個氣象學會學術論文獎了,果真是人生成就解鎖。為何演講中會提到海綿寶寶呢?因為這篇文章,講的是跟MJO有關,而MJO的故事,又跟海綿寶寶的比奇堡有關。
MJO這個近年來氣候學界非常熱門的議題,跟海綿寶寶的誕生有絕大的關係。MJO是Madden–Julian Oscillation的簡寫,是取名於發現的Madden與Julian這兩位學者。這兩位科學家在戰後1960年代,利用美軍於中太平洋試爆原子彈時所順便觀測的氣象資料,很聰明地提出了地球上有一種由西向東傳遞,時間尺度大約在三十到六十天繞地球一圈的震盪。MJO這種東西,對於氣候預報是非常有用的資訊,他對季風的肇始,對於臺灣梅雨的開始時間,對於颱風的生成,對於聖嬰的誕生與滅亡都有影響。
Hung, C.-w., and M. Yanai, 2004: Factors contributing to the
onset of the Australian summer monsoon.
Quart. J. Roy. Meteor. Soc., 130,
739-758. (SCI)
Hung, C.-w. and H.-H. Hsu, 2008: The First
Transition of the Asian Summer Monsoon, Intraseasonal Oscillation, and Taiwan Meiyu. J. Climate. 21, 1552–1568. (SCI)
之後呢,我們陸續又把臺灣不同季節跟MJO的相關給釐清,有關冬半年的部分,在這篇文章有詳細說明:
Hung, C.-w., H.-J. Lin and H.-H. Hsu, 2014: Madden–Julian Oscillation and the Winter Rainfall in Taiwan. J. Climate. 27, 4521-4530. DOI: 10.1175/JCLI-D-13-00435.1 (SCI)
本研究討論Madden–Julian
Oscillation(MJO)對臺灣冬半季(11月-4月)降雨的影響。結果顯示臺灣在MJO相位3及4時(MJO抵達印度洋與海洋大陸的西側),降 雨比較多,而在相位7及8時(西太平洋暖池海域),降雨比較少。本研究提出兩種機制說明此現象:(1)熱帶往中緯度傳送的波列:當MJO移動到中印度洋 時,激發了Matsuno-Gill 型態的波列。這是因為MJO的非絕熱加熱,其西側高層大氣會出現一個對稱於赤道的反氣旋距平。北側位於阿拉伯海及印度洋北側的反氣旋距平,將誘發向東北傳 送到中緯度的波列,這包括一個以東亞為中心,而會加強臺灣地區冬半季降雨的氣旋式距平。(2)MJO會增強從南海北傳的水氣供應:當MJO對流抵達海洋大 陸的蘇門達臘與爪哇時,向東發展的赤道區對流加強了低層的南來氣流,將水氣向北傳送到臺灣及華南地區。於是,因為南來水氣供應的增加,臺灣冬季季風的降雨 也會變多。
最後,則是台灣夏季降雨,西北太平洋颱風跟MJO,喔不,要改用BISIO的指數來看,一樣有關,也就是這次得獎得論文:
Hung C.-w. ,H.-J. Lin, P.-k. Kao, M.-f. Shih, W.-y. Fong, 2016:Impact of the Boreal Summer Intraseasonal Oscillation on the Western North Pacific Typhoons and Rainfall in Taiwan Terr. Atmos. Ocean. Sci.
(SCI)
因為有點懶得翻譯,英文摘要給大家參考,全文在此可以下載PDF
This study
discusses the boreal summer intraseasonal oscillation (BSISO) impact on the
western North Pacific (WNP) typhoons and the summer rainfall in Taiwan. The
real time BSISO1 and BISISO2 indices are created using the first two and the
third and fourth principal components of the multivariate empirical orthogonal
function analysis, based on outgoing long-wave radiation and zonal wind at 850
hPa from Lee et al. (2013). The results show that heavy rainfall in Taiwan and
the associated WNP typhoon frequency patterns are closely related to the 10 -
30 days BSISO2 phases during the typhoon season (July - October). Taiwan has
larger rainfall during BSISO2 phases 3, 4, and 5 when the major BSISO2
convection moves northwestward from the Philippine Sea to the Taiwan area.
During phases 3 and 4 the anomalous low-level cyclonic flow and the increased
typhoon frequency directly result in larger rainfall in Taiwan. Phase 5
exhibits enhanced low-level southwesterly flow which transports the moisture to
Taiwan responsible for more summer rainfall on the island.
其實今天的年會,還有頒發周佳學術論文獎,年度論文是我跟許晃雄老師指導的高培根博士獲得,而周佳這位我在UCLA非常照顧我的學長的愛徒陳昭安也得到研究新秀獎。我想,今天周佳一定也很替這些他的後輩們高興吧~ 就讓我們Rich get richer吧!
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