第26回サイエンスカフェ講演会・ICRE合同セミナーを下記のとおり開催します。

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講師：Ingo Richter博士　（海洋研究開発機構　研究員）

日時：２月２７日（水）　１３：１０～１４：４０

場所： B1-336 多目的室

講演題目：Challenges Facing GCM Models in the Tropical Atlantic Region

講演概要：
While the representation of tropical Pacific climate in　general circulation models (GCMs) has improved　substantially over the past two decades, the tropical Atlantic has largely resisted efforts by the community. Many current GCMs still fail to simulate the evolution of the equatorial Atlantic cold tongue in boreal summer and the performance of seasonal prediction systems is often matched by persistence forecasts. By analyzing output from a multi-model ensemble and by conducting sensitivity tests with one particular GCM, we show that equatorial Atlantic SST biases are largely due to weaker than observed equatorial easterlies in MAM, which deepen the thermocline one season before the peak of the observed cold tongue. Sensitivity tests demonstrate that the equatorial surface wind errors also contribute to the severe warm SST biases along the southwest African coast through Kelvin wave dynamics.
One cause for the equatorial surface wind biases is related to convection biases over tropical South America and Africa, which lead to a weakening of the Atlantic Walker circulation. Another reason is the tendency of the simulated intertropical convergence zone (ITCZ) to migrate south of the equator in MAM. Thus our results suggest that alleviating precipitation biases, particularly over tropical land surfaces, should be an important step toward improving simulation of the tropical Atlantic.

問い合わせ先：
相馬一義　（サイエンスカフェ）　内線：８３４５
馬籠　純　（ICREセミナー）　 　内線：８７２８