A piecewise-integration method for simulating the influence of external forcing on climate  

作　　者：Zhifu Zhang Chongjian Qiu Chenghai Wang 

机构地区：[1]Key Laboratory of ArM Climatic Changing and Reducing Disaster of Gansu Province, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China

出　　处：《Progress in Natural Science:Materials International》2008年第10期1239-1247,共9页自然科学进展·国际材料（英文版）

基　　金：supported by National Natural Science Foundation of China (Grant Nos.40575049,40633014,and 40575037)

摘　　要：Climate drift occurs in most general circulation models （GCMs） as a result of incomplete physical and numerical representation of the complex climate system, which may cause large uncertainty in sensitivity experiments evaluating climate response to changes in external forcing. To solve this problem, we propose a piecewise-integration method to reduce the systematic error in climate sensitivity studies. The observations are firstly assimilated into a numerical model by using the dynamic relaxation technique to relax to the current state of atmosphere, and then the assimilated fields are continuously used to reinitialize the simulation to reduce the error of climate simulation. When the numerical model is integrated with changed external forcing, the results can be split into two parts, background and pertur- bation fields, and the background is the state before the external forcing is changed. The piecewise-integration method is used to con- tinuously reinitialize the model with the assimilated field, instead of the background. Therefore, the simulation error of the model with the external forcing can be reduced. In this way, the accuracy of climate sensitivity experiments is greatly improved. Tests with a simple low-order spectral model show that this approach can significantly reduce the uncertainty of climate sensitivity experiments.气候飘移由于复杂气候系统的不完全的物理、数字的表示发生在很一般的发行量模型(GCM ) ，它可以在在外部强迫评估气候反应到变化的敏感实验引起大不确定性。解决这个问题，我们建议一个 piecewise 集成方法在气候敏感研究减少系统的错误。观察被使用动态松驰技术放松到空气的当前的状态第一吸收进一个数字模型，然后吸收领域连续地被用来重新初始化减少气候的错误的模拟模拟。当数字模型与改变的外部强迫是综合的时，结果能被分成二部分，背景和不安地，和背景在外部强迫被改变以前，是状态。piecewise 集成方法被用来连续地重新初始化有吸收领域的模型，而不是背景。因此，有外部强迫的模型的模拟错误能被减少。这样，气候敏感实验的精确性极大地被改进。测试与一简单低顺序光谱这条途径能显著地减少的模型表演气候敏感实验的不确定性。

关 键 词：Climate model External forcing Sensitivity experiment Low-order spectral model Dynamic relaxation technique 

分 类 号：P46[天文地球—大气科学及气象学]