Assessing and Understanding Extratropical Control on Tropical Climate

人们早就认识到热带气候和变率可能受到温带气候过程的影响。以往关于温带对热带的影响的研究基本上是定性的，而且是从海洋-大气完全耦合的角度进行的。因此，温带气候对热带气候的影响在很大程度上仍未得到探索。该项目的目的是研究温带气候对热带气候的影响，重点是量化热带气候的温带影响及其变率。该项目将使用一种称为区域耦合数据同化（RCDA）的新型建模方法，该方法将耦合数据同化与耦合气候动力学相结合，以评估和了解现实世界中温带气候对热带气候的影响。在RCDA中，温带观测资料被同化到气候模式中，而热带海洋-大气过程保持完全耦合。这样就可以定量评估和了解温带对热带气候学和热带气候变率的影响，例如ENSO。研究小组还将在耦合的一般环流模式中探讨温带气旋对热带偏置的影响。这项资助的研究结合了耦合数据同化和耦合气候动力学，代表了对热带气候和热带气候变率的温带影响的系统研究。这项工作将发展一种新的模式策略，以评估和理解温带气候变率对热带气候学和气候变率的影响。这种理解将有助于进一步改进气候模型，用于气候预测、未来气候预测，以及它们的社会影响。这个项目将培养两名研究生。

It has long been recognized that tropical climate and variability can be affected by climate processes in the extratropics. Previous studies on the extratropical impact on the tropics have remained largely qualitative in nature and from the fully coupled ocean-atmosphere perspective. As such, the impact of extratropical climate on tropical climate has remained largely unexplored. The goal of this project is to investigate the extratropical impact on tropical climate with the focus on quantifying extratropical influences of tropical climate and its variability. The project will use a novel modeling approach called Regional Coupled Data Assimilation (RCDA) approach, which combines coupled data assimilation with coupled climate dynamics, to assess and understand the extratropical climate impact on tropical climate for the real world. In RCDA, observations in the extratropics are assimilated in climate models while the tropical ocean-atmosphere processes remain fully coupled. This allows the quantitative assessment and understanding of the extratropical impacts on both tropical climatology and tropical climate variability, such as ENSO. The research team will also explore the extratropical impact on the tropical bias in coupled general circulation models. The funded research represents a systematic study of the extratropical impact on tropical climate and tropical climate variability that combines coupled data assimilation with coupled climate dynamics. This work will develop a new modeling strategy to assess and understand the impact of extratropical climate variability on tropical climatology and climate variability. This understanding will help further improve climate models for climate predictions, future climate projections, and, in turn, their societal impacts. This project will train two graduate students.