谱逼近方法对区域气候模式性能的改进:不同权重函数的影响  

Impact of the spectral nudging on the simulation of a regional climate model: Different weight function

作　　者：曾先锋[1,2,3] 周天军[1] 

机构地区：[1]中国科学院大气物理研究所大气科学与地球流体力学数值模拟国家重点实验室,北京100029 [2]中国科学院研究生院,北京100049 [3]兰州军区空军气象中心,兰州730020

出　　处：《气象学报》2012年第5期1084-1097,共14页Acta Meteorologica Sinica

基　　金：海洋公益性行业科研专项(201105019-3);国家高新技术研究发展计划(863计划)项目(2010AA012304);中国科学院知识创新工程项目(KZCX2-YW-Q11-04);(中-英-瑞)中国适应气候变化项目--气候科学

摘　　要：为减小区域气候模式环流模拟偏差,对RegCM3中的风场采用谱逼近方法,并以2003年江淮梅雨过程为例,检验了谱逼近方法对模拟效果的改进能力。结果表明,采用谱逼近方法后,模拟技巧得到显著提高,能明显改进模式对梅雨过程的模拟能力,校正了模式模拟的梅雨期环流和梅雨锋偏北导致降水偏北的偏差。针对谱逼近方法中权重函数及其强度系数的敏感性数值试验表明,谱逼近方法的改进效果主要决定于强度系数的选择。采用von Storch等2000年提出的权重函数且强度系数取为0.05时改进效果最显著。但谱逼近方法并不能完全解决区域气候模拟面临的问题,该方法能够保证大气环流更接近强迫场,也能较大程度地改进模式对梅雨期降水位置和强度的模拟,但对于与模式物理过程联系更紧密的低层大气温度及高温高湿中心的南北位置等的模拟,则仍有赖于模式物理过程的进一步改进。The spectral nudging technique is incorporated into wind fields in the regional climate model, RegCM3, and validated with the 2003 meiyu event. The results show that, with the spectral nudging, the ability of the model to simulate a local short- time scale climate scenario, such as the meiyu event, can be improved obviously. It can correct efficiently the circulation and meiyu front northward biases which induce the precipitation northward biases during the meiyu produced by the model. Fur- thermore, two key variables to the spectral nudging., the weight function and the intensity index are tested. From the compari- son among two weight functions and two corresponding intensity indices respectively, we find that the improvement of the spec- tral nudging depend mainly on the intensity coefficient. The spectral nudging with the weight function designed by von Stortch, et al. in 2000 and the intensity coefficient set to 0.05, gets the greatest improvement in the simulation of 2003 meiyu among the five experiments. Although the spectral nudging can make simulated circulation close to the forcing fields and the position and intensity of meiyu rainbelt close to the observation, respectively, this technique can not eliminate all the biases of the model. The better simulation of those variables that are closely related to physics processes, such as the positions of the low level tem- perature and the high temperature and high humid areas, should be relied on the further physics process improvement.

关 键 词：谱逼近 REGCM3模式 梅雨 

分 类 号：P435[天文地球—大气科学及气象学]