Collaborative Research: Understanding Congo Rainfall Variability and Trends

中部非洲的森林是地球上最干燥和第二大的森林，经历了长期的干旱趋势。最近的一项研究发现，刚果盆地的森林光合作用能力普遍下降，并将这种大规模下降至少部分归因于这种干旱趋势。该地区持续干旱可能会改变刚果森林的组成和结构，从而可能有利于耐旱物种的传播，从而影响生物多样性、碳储存和全球水循环。了解干旱的性质和原因并评估其对森林的影响具有重要的社会、环境和经济意义。由于政治、经济和历史因素，缺乏观测和资源，极大地阻碍了对刚果盆地气候变异性的了解。在该项目下，将进行观测和模拟研究相结合的研究，以调查刚果20世纪降雨量变化的性质和原因。我们将研究全球海洋表面温度的作用。对于观测部分，将利用观测和再分析数据来确定变化的主要模式和驱动因素。在模拟部分，将研究耦合模式相互比较项目(CMIP5)模拟和理想化气候模式模拟，以研究刚果干旱的物理机制。将调查人为强迫和自然强迫对刚果盆地观测到的降雨量年代际变化的相对贡献。

Central African forests, the driest and second largest on Earth, have experienced a long-term drying trend. A recent study detected a widespread decline in forest photosynthetic capacity over the Congo Basin and attributed this large-scale decline, at least partially, to this drying trend. Persistent drought in the region could alter the Congolese forest composition and structure in a manner that might favor the spread of drought tolerant species and thus impact biodiversity, carbon storage, and the global water cycle. Understanding the nature and cause of this drought and assessing its impacts on the forests are of significant societal, environmental, and economic importance. Understanding of climatic variability in the Congo basin is greatly hindered by a lack of observations and resources due to political, economic and historical factors. Under this project, a combination of observational and modeling studies will be undertaken to investigate the nature and cause of the Congo rainfall variability in the 20th century. The role of global sea surface temperatures will be examined. For the observational component, observations and reanalysis data will be utilized to identify major patterns and drivers of the variability. For the modeling component, the Coupled Model Intercomparison Project (CMIP5) simulations and idealized climate model simulations will be examined to investigate the physical mechanisms for the Congo drought. The relative contribution of anthropogenic versus natural forcing on the observed rainfall decadal variability over the Congo Basin will be investigated.