本計畫延續人為氣膠對熱帶降雨的影響(MOST 103-2111-M-034 -003)之研究。在氣膠冷卻效應下，熱帶降雨的空間變化與溫室氣體的增溫影響相當類似，但是變化的符號相反。我們發現主要對流區傾向於移動到次要對流區（例如：由赤道西太平洋移動到印度洋），南太平洋輻合帶（South Pacific Convergence Zone ，SPCZ)也有明顯的位移，這樣的反應並未在暖化模擬中出現，也未在過去相關研究的冷化實驗出現（使用較簡單的模式及較低的空間解析度），代表氣候系統對不同的輻射驅力會透過不同機制產生變化達到不同的氣候平衡態，雖然各種輻射驅力對氣候系統的共同效應無法以簡單疊加的方式得知，透過探討氣候系統對個別輻射驅力的反應，仍有助於我們對氣候系統的動力過程有更深入的瞭解。本計畫使用Community Earth System Model version 1 (CESM1) 搭配一中等複雜度的氣候模式（the University of California, Los Angeles Quasi-Equilibrium Circulation Mode, UCLA QTCM）進行同樣的冷化實驗，先測試空間解析度是否為造成模擬結果差異的因素，並探討熱帶對流高度及環流型態如何透過海氣交互作用在全球溫度改變時產生變化。目前分析過的四組模式中，主要對流區出現的位置並不一致，我們亦將使用氣候變遷聯盟開發之Taiwan Earth System Model (TaiESM) 探討不同模式參數化是否會造成對流位置的模擬差異及其對熱帶大尺度環流強度及厚度可能產生的影響。
This is an extent research based on the results of climate impacts from anthropogenic aerosols on tropical precipitation using four CMIP 5 simulations (MOST 103-2111-M-034 -003). In the previous project, we found the tendency of tropical precipitation change due to aerosol cooling effect is nearly opposite to that of greenhouse gases in terms of its spatial pattern. The most important findings are the shift of major convective area (from western Pacific warm pool to India Ocean) and the shift of South Pacific Convergence Zone (SPCZ) which are not documented and discussed in any research. We propose to perform the same cooling simulation using the Community Earth System Model version 1 (CESM1) and use an intermediated complex climate model (the University of California, Los Angeles Quasi-Equilibrium Circulation Mode, UCLA QTCM) to investigate the possible processes that may modify tropical convection and circulations in the cooling simulations. We will analyze moisture budget and moist static energy budget and discuss influences from sea surface temperature spatial patterns and values. In our previous study, the major convective area appears differently in different models which may be due to model parameterizations. We will also investigate the influences from convection parameterizations or other schemes on tropical convection and large-scale circulations using the Taiwan Earth System Model (TaiESM) from the main project.
