人為活動放出溫室氣體及氣膠，分別具有暖化與冷化的效應。大尺度的溫度變化造成熱帶環流及降水空間分布有明顯的改變，冷、暖兩種不同的效應造成的影響及其可能的氣候動力機制，在過去10年來已有一些研究成果，但海洋所扮演的角色尚未被詳細探討過。綜合過去的研究可知，部分熱帶大尺度環流及降水分布的變化具有冷、暖對稱的反應，但哈德里胞的強度變化及間熱帶輻合區(Intertropical Convergence Zone, ITCZ)的移動，則不具有此對稱變化。根據我們過去的研究結果，冷化時，哈德里胞及ITCZ的變化在氣候模式間具有明顯的一致性（哈德里胞一致的增強與ITCZ往南移動）。Hill et al. (2015)的結果指出由哈德里胞傳送的能量在暖化實驗中隨季節有明顯的南北方向的變化，但在冷化實驗中並無此年週期變化，可用來解釋我們發現的一致性。由氣候驅力產生的海表面溫度變異(Sea Surface Temperature Anomaly, SSTA)可以分成「平均變異」及「空間分布」兩部分，Hill et al. (2015) 指出，冷、暖兩種情況的大氣環流及其相關的經向能量傳送分別與不同的SSTA分量有關。因此，在此計畫中，將使用兩種不同複雜度的氣候模式(SPEEDY and CESM1)來模擬不同SSTA分量對大氣環流的影響，計算相關的經向能量傳送，探討高低緯度的能量差異如何透過海溫變異項及大氣經向環流或渦流能量傳送。
Human activities release greenhouse gases (GHGs) and aerosols which produce global warming and cooling, respectively. During the past years, several climate mechanisms have been suggested to explain the changes of tropical precipitation and large-scale circulation, and the position of the ITCZ due to global temperature change. However, the role of ocean is not explored in details, yet. We have found that some of the precipitation and circulation pattern changes show symmetric responses between warming and cooling, but the strength of Hadley cell and the position shift of the ITCZ are the exceptions. According to our past results, the strength of Hadley cell enhanced consistently between models in cooling simulations. The consistence of ITCZ shifting is clear in cooling simulations as well. Hill et al. (2015) showed that there is clear seasonal cycle in the meridional energy transport by Hadley cell in the warming simulation, but the seasonality does not exist in the cooling simulation, which may be used to support the consistence we found in our research. The SST anomaly induced by climate forcings (GHGs or aerosols) may be decomposed into a mean anomaly and the spatial patterns, which are associated with different atmospheric circulation components. We will investigate effects of the two SSTA components using a simplified global circulation model called SPEEDY and a standard climate model called CESM1. Then calculate the meridional energy transport by the mean meridional circulations and eddies to understand the details of the processes.
