Effects of Surface Conditions on Tropical Precipitation

这项研究的目的是帮助我们理解非洲和南美洲的降水分布是如何确定的。调查将通过比较不同复杂程度的气候模型进行。分析将侧重于了解热带大气动力学如何对特定的陆地表面条件和海洋表面温度(SST)异常作出反应，以及这种反应如何改变陆地上的降水模式。重点是使用气候模型来阐明物理机制，而不是尽可能地产生最真实的模拟。使用大气环流模式(GCM)的试验将被用来分离SST分布和陆面属性(如土壤湿度、地表反照率和粗糙度)对热带大陆降水场的影响。GCM上的线性化版本将用于进一步诊断GCM的响应。与更复杂的GCM模拟和观测结果的比较将被用来将结果与真实气候联系起来。这项研究很重要，因为它试图加强关于陆地表面特性如何影响气候的知识。

The purpose of this research is to contribute to our understanding of how precipitation distributions are established over Africa and South America. The investigation will be conducted by comparisons among climate models of various degrees of complexity. Analysis will focus on understanding how the tropical atmospheric dynamics responds to specified land surface conditions and sea surface temperature (SST) anomalies, and how this response modifies precipitation patterns over land. The focus is on using climate models to illuminate physical mechanisms, not to generate the most realistic simulation possible. Experiments with a general circulation model (GCM) will be used to isolate the effects of SST distributions and land surface attributes, such as soil wetness, surface albedo and roughness, on the continental precipitation field in the tropics. A linearized version on the GCM will be used to further diagnose the GCM's response. Comparisons with more complex GCM simulations and with observations will be used to relate results to the real climate. This research is important because it attempts to enhance knowledge about how land surface properties affect climate.