AGCM simulations of intraseasonal variability associated with the Asian summer monsoon
AGCM simulations of intraseasonal variability associated with the Asian summer monsoon
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DOI：
10.1007/s00382-003-0337-1
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发表时间：
2003-08
期刊：
影响因子：
4.6
通讯作者：
D. Waliser;K. Jin;In-Sik Kang;W. Stern;Siegfried D. Schubert;Man-Li C. Wu;Ka-Ming Lau;Myong-In Le
中科院分区：
文献类型：
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作者：
D. Waliser;K. Jin;In-Sik Kang;W. Stern;Siegfried D. Schubert;Man-Li C. Wu;Ka-Ming Lau;Myong-In Le
本文分析了几个大气环流模式（AGCMs）模拟的亚洲夏季风季节内变率，并与观测资料进行了比较。模式数据来自CLIVAR/Asian-Australian Monsoon Panel发起的Monsoon GCM Intercomparison项目。10个GCM组，即，海洋-陆地-大气研究中心（COLA）、数值数学研究所（DNM）、戈达德航天飞行中心（GSFC）、地球物理流体动力学实验室（GFDL）、大气物理研究所（IAP）、印度热带气象研究所（IITM）、气象研究所（MRI）、国家大气研究中心（NCAR）、首尔国立大学（SNU）、和纽约的州立大学（SUNY）参加了该项目的季节内部分。每个进行了一组10个集合模拟1996年9月1日至1998年8月31日，使用相同的观测每周SST值，但不同的初始条件。重点是与降雨的季节内变率（ISV）相关的空间和季节变化，每个模型的降雨时空变化的主要模式的结构[即它们对季节内振荡（ISO）的描述]，与每个模型的ISO相关的遥相关模式，以及模型的ISV对季节性季风可预测性的影响。结果表明，几个模型表现出的ISV水平或以上，发现在观察与空间模式的ISV，类似于观察到的模式。这包括一些相当详细的特征，包括海洋和陆地区域之间变异的相对分布。在面积平均方差方面，发现代表NH夏季与冬季ISV的模型的保真度似乎是密切相关的。此外，大多数模式的ISO模式确实表现出某种形式的东北传播。然而，模式ISO模式通常是不太连贯，缺乏足够的向东传播，并具有较小的纬向和纬向空间尺度比观察到的模式，并往往局限于一侧或另一侧的海洋大陆。模型对ISV和/或ISO模式的描述中最普遍和最有问题的特征是赤道印度洋总体上缺乏变化。在某些情况下，这种特征似乎是由于一些模式在赤道周围形成了双辐合区，而不是赤道上的一个强辐合区。这一缺陷导致了当地降雨模式的代表性差，也显着影响了模式的代表性的全球尺度遥相关模式与ISO。最后，模式集合的分析表明，一个模式的降雨的ISV的强度和季节性季风降雨的集合内的变化之间的正相关关系。后一种关系的影响进行了讨论的背景下，季节性季风的可预测性。
The intraseasonal variability associated with the Asian summer monsoon as simulated by a number of atmospheric general circulation models (AGCMs) are analyzed and assessed against observations. The model data comes from the Monsoon GCM Intercomparison project initiated by the CLIVAR/Asian–Australian Monsoon Panel. Ten GCM groups, i.e., the Center for Ocean–Land–Atmosphere Studies (COLA), Institute of Numerical Mathematics (DNM), Goddard Space Flight Center (GSFC), Geophysical Fluid Dynamics Laboratory (GFDL), Institute of Atmospheric Physics (IAP), Indian Institute of Tropical Meteorology (IITM), Meteorological Research Institute (MRI), National Center for Atmospheric Research (NCAR), Seoul National University (SNU), and the State University of New York (SUNY), participated in the intraseasonal component of the project. Each performed a set of 10 ensemble simulations for 1 September 1996–31 August 1998 using the same observed weekly SST values but with different initial conditions. The focus is on the spatial and seasonal variations associated with intraseasonal variability (ISV) of rainfall, the structure of each model's principal mode of spatial-temporal variation of rainfall [i.e. their depiction of the Intraseasonal Oscillation (ISO)], the teleconnection patterns associated with each model's ISO, and the implications of the models' ISV on seasonal monsoon predictability. The results show that several of the models exhibit ISV levels at or above that found in observations with spatial patterns of ISV that resemble the observed pattern. This includes a number of rather detailed features, including the relative distribution of variability between ocean and land regions. In terms of the area-averaged variance, it is found that the fidelity of a model to represent NH summer versus winter ISV appears to be strongly linked. In addition, most models' ISO patterns do exhibit some form of northeastward propagation. However, the model ISO patterns are typically less coherent, lack sufficient eastward propagation, and have smaller zonal and meridional spatial scales than the observed patterns, and are often limited to one side or the other of the maritime continent. The most pervasive and problematic feature of the models' depiction of ISV and/or their ISO patterns is the overall lack of variability in the equatorial Indian Ocean. In some cases, this characteristic appears to result from some models forming double convergence zones about the equator rather than one region of strong convergence on the equator. This shortcoming results in a poor representation of the local rainfall pattern and also significantly influences the models' representations of the global-scale teleconnection patterns associated with the ISO. Finally, analysis of the model ensemble shows a positive relationship between the strength of a model's ISV of rainfall and its intra-ensemble variability of seasonal monsoon rainfall. The implications of this latter relation are discussed in the context of seasonal monsoon predictability.