SGER: Understanding Tropical-Subtropical Forcing and Predictability of Long-Term North American Drought in Coupled Models

SGER：了解耦合模型中的热带-亚热带强迫和北美长期干旱的可预测性

• 批准号: 0739658
• 负责人: Kristopher Karnauskas
• 金额: $ 3万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0739658&HistoricalAwards=false
• 关键词: SGER; Understanding; Tropical; Subtropical; Forcing

This is a grant under a Climate Variability and Predictability (CLIVAR) Program pilot project called DRICOMP, for the Drought in Coupled Models Project, which focuses on making initial explorations into the mechanisms of drought as they are represented in the output of global climate models and on attempting to assess the reliability of these models in simulating drought.A growing body of literature indicates that El Nino - Southern Oscillation (ENSO) is a fundamental driver of global drought variability and that La Nina-like conditions play a key role in the circulation anomalies leading to North American drought. An important yet poorly understood process with strong implications for understanding and predicting long-term North American drought is how the coupled ocean-atmosphere system maintains persistent cool conditions in the equatorial Pacific Ocean.This project will make an initial attempt to answer four questions: (1) how are persistent cool episodes in the equatorial Pacific Ocean represented in state-of-the-art coupled climate models, (2) through what physical mechanisms do such conditions lead to persistent North American drought, (3) how can an understanding of such questions serve to extend the predictive lead time for long-term North American drought, and (4) how do the mechanisms and prospects for predictability depend on the essence of a climate in transition?A two-pronged approach will be taken: first, a selection of coupled models as determined from the details of their ocean component will be used to characterize and explain the representation of persistent cool equatorial Pacific conditions; secondly, long-term North American drought variability (in terms of the Palmer drought severity index - PDSI) and its relationships with the equatorial Pacific, including how that appears to depend on anthropogenic forcing, will be analyzed in the full suite of Climate Model Intercomparison Project 3 (CMIP3) climate models. The problem of predictability at extended lead times will be explored by ascertaining how the remote forcing field itself (i.e., low-frequency evolution of equatorial Pacific SST) is modulated, and the coherence between that signal and the PDSI.Broader impacts of these are in its potential contribution to improved prediction of North American drought at extended leads and in supporting the principal investigator, who is a graduate student.

This is a grant under a Climate Variability and Predictability (CLIVAR) Program pilot project called DRICOMP, for the Drought in Coupled Models Project, which focuses on making initial explorations into the mechanisms of drought as they are represented in the output of global climate models and on attempting to assess the reliability of these models in simulating drought.A growing body of literature indicates that El Nino - Southern Oscillation (ENSO) is a fundamental driver of global干旱的变异性和类似拉尼娜的状况在导致北美干旱的流通异常中起着关键作用。 An important yet poorly understood process with strong implications for understanding and predicting long-term North American drought is how the coupled ocean-atmosphere system maintains persistent cool conditions in the equatorial Pacific Ocean.This project will make an initial attempt to answer four questions: (1) how are persistent cool episodes in the equatorial Pacific Ocean represented in state-of-the-art coupled climate models, (2) through what physical mechanisms do such conditions lead to （3）对此类问题的理解如何延长北美长期干旱的预测提前时间，（4）（4）可预测性的机制和前景如何取决于过渡中气候的本质？首先，将采取两种规定的方法：首先，偶尔的详细信息可以确定偶数的详细信息，并以众多的态度来确定态度的态度，并解释了特定的特征。其次，将在气候模型介绍项目3（CMIP3）气候模型中分析长期的北美干旱变异性（就Palmer干旱严重程度指数-PDSI而言）及其与赤道太平洋的关系及其与赤道太平洋的关系。 通过确定远程强迫场本身（即赤道太平洋SST的低频演变）如何进行调节，并调节该信号和PDSI之间的一致性。这些信号对这些信号的影响是对北美的潜在贡献，在扩展的领导者的潜在贡献中，该信号的潜在贡献是对学生的潜在贡献。