Collaborative Research into Indo-Asian Monsoon Variability: Data and Model Assessment of Northern- and Southern-Hemisphere Mechanisms

根据这一奖项，PIS将生成和分析亚洲季风系统在目前之前500万至200万年间的替代记录，并运行一套由8个GCM实验组成的核心实验，这些实验将测试关于导致印度和亚洲季风增强和演变的关键气候过程的三个假设：1)北半球夏季风的强烈时间对南半球的潜热输出比对亚洲地区直接感热加热更敏感。2)北半球大范围冰量的启动和发展加强了冬季季风。3)冬季和夏季风环流的强度与北半球的冰川演化是动态耦合的，并与北半球的冰川演化有关。利用地质记录验证这些假设将通过分析和比较3.2 Ma至今快速演化的高冰量区间和温暖、相对稳定的最小冰期5至3.2 Ma期间的季风响应来完成。在地球历史的两个不同的大尺度边界条件下分析季风变化的联合数据/模型策略将使在轨道时间尺度上区分负责季节季风变化的内部(气候反馈)和外部(太阳)机制。

Under this award the PIs will generate and analyze proxy records of the Asian monsoon system over the interval from 5 to 2 million years before present and to run a core set of eight GCM experiments which will test three hypotheses regarding key climate processes that lead to intensification and evolution of the Indian and Asian monsoons:1) The timing of strong Northern Hemisphere summer-monsoons is more sensitive to the export of latent heat from the Southern Hemisphere than to direct sensible heating over Asia.2) The initiation and development of large-scale ice volume in the Northern Hemisphere strengthens the winter monsoon, weakens the summer monsoon and is the root cause of the observed non-stationary phase response relative to orbital forcing (i.e. the timing of the strongest summer-monsoon drifts relative to insolation forcing).3) The intensity of winter- and summer-monsoon circulation is dynamically coupled and linked to glacial evolution in the Northern Hemisphere. Testing these hypotheses using the geological record will be accomplished by analyzing and comparing the monsoon response during the rapidly evolving, high ice-volume interval from 3.2 Ma to present and the warm, relatively stable, minimal ice interval 5 to 3.2 Ma. The combined data/model strategy of analyzing monsoon variability during two intervals of Earth history with very different large-scale boundary conditions will enable differentiation of internal (climate feedback) and external (insolation) mechanisms responsible for seasonal monsoon variability at orbital time scales.