澳大利亞氣象局表示: 進入拉尼娜現象的早期階段
過去兩週，熱帶太平洋水溫持續變冷，現已接近拉尼娜水平。其他ENSO的指標也達到或越過拉尼娜的門檻。同時，電腦模式預測中太在未來幾個月內也會持續降溫，現在很有可能進入拉尼娜的早期階段，2010年將被視為拉尼娜年。
太平洋氣溫穩步下降，現在在赤道一些地區海溫比正常偏低1度。
南方濤動指數（SOI）增加，現在大約+14。信風強於正常水平，赤道中太平洋雲量減少。這些指標都預示著進入拉尼娜早期階段。
拉尼娜期間一般會但也不是絕對地——澳大利亞的大部分地區今年下半年雨量會超出正常水平，尤其是東部和北部地區。夜溫會高於平常，澳大利亞北部在風季受到熱帶氣旋侵襲的風險在增加。
translate from AUS 氣象局
Tropical Pacific Ocean temperatures continued to cool over the past fortnight, and are now approaching levels typical of a La Niña. Similarly, other ENSO indicators are also at or exceeding La Niña thresholds. As computer models predict the central Pacific will continue to cool over the coming months, it is now highly likely that the Pacific is in the early stages of a La Niña event, and that 2010 will be considered a La Niña year.
Signs of an emerging La Niña event have been apparent in the equatorial Pacific for several months. Pacific Ocean temperatures have cooled steadily throughout the year and are now more than 1°C cooler than average in some areas on the equator. The Southern Oscillation Index (SOI) has increased in value and is currently around +14, trade winds continue to be stronger than average and cloudiness has remained suppressed over the central Pacific. All of these key indicators are at levels typical of the early stages of a La Niña event.
La Niña periods are usually, but not always, associated with above normal rainfall during the second half of the year across large parts of Australia, most notably eastern and northern regions. Night time temperatures are typically warmer than average and Tropical Cyclone risk for northern Australia increases during the cyclone season (November-April).
反聖嬰現象持續發展中,且有加快的趨勢
最新的海表溫距平依舊顯示西太平洋海溫持續偏高
尤其是南海最為明顯
不過前兩個颱風似乎並未因此有爆發性的增強
而赤道中東太平洋海溫則有進一步降低,距平持續偏低
這些更加刺激反聖嬰加速發展
赤道西太海溫較高因此空氣受海溫加熱影響密度較小因此氣流上升,整體氣壓低於平均
赤道東太海溫偏低,空氣密度較大,盛行下沉氣流,整體氣壓高於平均
因此向東吹的赤道貿易風強度也高於平均
因此理論上較強之對流發展應該會處於西太平洋的
赤道海域垂直剖面距平圖中
最近這個月整體西太從淺層至深層海水皆呈現偏暖趨勢
中東太平洋則依舊被較冷水團覆蓋著
西太在這種情形更佳利於颱風發展
原因在颱風在海面上時,
強勁風力不只影響表層海水
較深層之海水也將被捲上表層
而由於此時整個垂直高度海溫皆偏高
因此不管颱風如何攪上深層海水,依舊將處在溫暖海域上!!
SOI指數在上次跌到一個谷底後
馬上現在快速及轉直上,斜率大的嚇人
目前大概已經登上20了...
反聖嬰的發展狀況在此展現的淋漓盡致
完全反映此時正快速的發展
部分學者甚至預測今年反聖嬰強度有機會來到中等
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