RAPID: Predictability of Atmospheric Teleconnections in Initialized Decadal Forecasts

这是由一封亲爱的同事来信(NSF 11-006)资助的16个快速反应(RAPID)项目之一，该信鼓励对为政府间气候变化专门委员会第五次评估报告(IPCC AR5)准备的气候模型模拟进行诊断分析。在这些项目中进行的研究预计将导致更详细的模型相互比较，更好地理解稳健的模型行为，以及更好地理解和量化未来气候模拟中的不确定性。这个项目考虑了为AR5准备的后播模拟中十年气候变化的潜在可预测性。这些为期10年的后预测实验是用模式进行的，其中海洋属性，主要是海洋表面温度(SST)，从1960年开始每五年使用一次观测数据进行初始化，另外从1960年、1980年和2005年开始进行30年后预测(实际上是后来几年的预测)。后预报实验是AR5中的一个新特征，在第四次评估报告中没有对应的特征，它们旨在确定在考虑到海洋状况和预报期开始的情况下，与政策制定者相关的十年尺度气候变化的可预测性程度。在该项目中进行的研究评估了后预报集合中可在十年时间尺度上可预测的太平洋和印度洋SST异常所强迫的大气遥相关的技能。通过比较观测到的和观测到的降雨、气温和环流异常的模式来评估技能。此外，还与20世纪因温室气体增加和其他外力(例如火山、气溶胶和太阳变率)而被迫进行的未初始化模拟进行了比较，从而可以评估可预测性在多大程度上取决于外部强迫而不是初始的内部变率。该项目的更广泛影响在于它支持IPCC AR5，该项目旨在向世界各地的决策者提供关于气候变化及其后果的信息。成功的十年气候预测对于资源管理者制定知情的适应战略可能是有价值的，但首先必须确定这种预测的可实现程度。

This is one of 16 Rapid Response (RAPID) projects funded as the result of a Dear Colleague Letter (NSF 11-006) encouraging diagnostic analyses of climate model simulations prepared for the Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5). Research conducted in these projects is expected to lead to more detailed model intercomparisons, better understanding of robust model behaviors, and better understanding and quantification of uncertainty in future climate simulations. This project considers the potential predictability of decadal climate variabiality in hindcast simulations prepared for the AR5. These 10-year hindcast experiments are performed with models in which ocean properties, principally sea surface temperature (SST), are initialized using observations every five years starting in 1960, with additional 30-year hindcasts starting in 1960, 1980, and 2005 (actually a forecast in the later years). The hindcast experiments are a novel feature in AR5 with no counterpart in the Fourth Assessment Report, and they are designed to determine the extent to which decadal-scale climate changes of relevance to policy makers are predictable given the state of the ocean and the beginning of the forecast period.Research conducted in this project assess the skill of atmospheric teleconnections forced by SST anomalies in the Pacific and Indian Oceans that are predictable on decadal timescales in the hindcast ensemble. Skill is assessed by comparisons between observed and hindcasted patterns of rainfall, air temperature, and circulation anomalies. Additional comparisons are performed with uninitialized simulations of the 20th century forced by greenhouse gas increases and other external forcings (e.g. volcanos, aerosols, and solar variability), so that the extent to which predictability depends on external forcing rather than initialized internal variability can be assessed.The broader impact of the project lies in its support of the IPCC AR5, which is intended to provide information on climate change and its consequences to decision makers worldwide. Successful decadal climate forecasts could be of value to to resource managers developing informed adaptation strategies, but first the degree to which such forecasts are achievable must be determined.