Tropical Pacific Decadal Variability and Its Impact on the Atmosphere in Climate Models

热带太平洋的年代际变率对全球气候有很大的影响，它使我们区分自然气候变化和人为气候变化的能力变得复杂。因此，更好地了解造成这种变化的机制，对于评估热带海洋的可预测性及其对当地和偏远地区气候的影响至关重要。这项研究将利用为政府间气候变化专门委员会第四次评估报告进行的试验，审查全球气候模式集合输出中热带太平洋的十年变率。将查明有关的物理过程沿着起源区域，这些区域强迫将与大尺度大气环流有关，该项目还将研究未来气候中可能出现的十年变率的特征，沿着这种未来变率对人类重要的气候变化的影响，如美国的降雨量。这项工作将结合对现有模型输出的深入诊断和使用海洋模型的敏感性实验。鉴于地面风强迫对十年变化的核心作用，这些实验将在不同地区应用异常风强迫，以确定十年时间尺度上异常风的关键强迫区域和关键方面。对于具有更现实的年代际变化的气候模式，相关的风强迫将与大尺度大气环流相关，以确定该强迫的前兆和热带海表温度变化导致的大尺度大气异常。气候变化模拟将被用来研究在一个温暖的气候变化的特点，沿着其全球影响。这项工作的更广泛的影响包括与博士合作。科罗拉多大学的学生。进一步了解热带太平洋目前和未来气候的十年变化将有助于评估美国持续干旱的可预测性。

Tropical Pacific decadal variability can have large impacts upon the global climate, and it complicates our ability to separate anthropogenically induced trends from natural climate variations. Improved understanding of the mechanisms responsible for such variability is, therefore, fundamental for assessing the predictability of the tropical oceans and their local and remote climate influences. This study will examine tropical Pacific decadal variability in the output of an ensemble of global climate models using runs carried out for the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Relevant physical processes will be identified, along with their regions of origin, and these regional forcings will be related to the large-scale atmospheric circulation.The project will also examine the features of decadal variability likely to emerge in future climates, along with the impacts of this future variability on climate variations important to people, such as rainfall over the United States. The work will use a combination of in-depth diagnostics of existing model output and sensitivity experiments using an ocean model. Given the central role of surface wind forcing for decadal variations, these experiments will apply anomalous wind forcing in different areas, in order to identify key forcing regions and key aspects of the anomalous winds at decadal timescales. For climate models with more realistic decadal variations, the associated wind forcing will be related to the large-scale atmospheric circulation to identify precursors of that forcing and large-scale atmospheric anomalies resulting from the tropical sea surface temperature variations. Climate change simulations will be used to examine the characteristics of decadal variability in a warmer climate, along with its global influences.Broader impacts of this work include collaboration with a Ph.D. student at the University of Colorado. Improved understanding of tropical Pacific decadal variability in present and future climates will help in assessing the predictability of persistent droughts over the United States.