Quantifying the attribution of model bias in simulating summer hot days in China with IAP AGCM 4.1  

作　　者：LIN Zhao-Hui YU Zheng ZHANG He WU Cheng-Lai 

机构地区：[1]International Center for Climate and Environment Sciences(ICCES),Institute of Atmospheric Physics(IAP),Chinese Academy of Sciences [2]Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science & Technology [3]College of Earth Science,University of Chinese Academy of Sciences

出　　处：《Atmospheric and Oceanic Science Letters》2016年第6期436-442,共7页大气和海洋科学快报（英文版）

基　　金：supported by the Special Scientific Research Fund of the Meteorological Public Welfare Profession of China[grant number GYHY01406021];National Key Research and Development Program[grant number 2016YFC0402702];the National Natural Science Foundation of China[grant numbers 41575095,41175073]

摘　　要：Using lAP AGCM simulation results for the period 1961-2005, summer hot days in China were calculated and then compared with observations. Generally, the spatial pattern of hot days is reasonably reproduced, with more hot days found in northern China, the Yangtze and Huaihe River basin, the Chuan-Yu region, and southern Xinjiang. However, the model tends to overestimate the number of hot days in the above-mentioned regions, particularly in the Yangtze and Huaihe River basin where the simulated summer-mean hot days is 13 days more than observed when averaged over the whole region, and the maximum overestimation of hot days can reach 23 days in the region. Analysis of the probability distribution of daily maximum temperature （Trnax） suggests that the warm bias in the model-simulated Tmax contributes largely to the overestimation of hot days in the model. Furthermore, the discrepancy in the simulated variance of the Tmax distribution also plays a non- negligible role in the overestimation of hot days. Indeed, the latter can even account for 22% of the total bias of simulated hot days in August in the Yangtze and Huaihe River basin. The quantification of model bias from the mean value and variability can provide more information for further model improvement.本文利用IAP大气环流模式1961–2005年的模拟结果,分析发现模式虽然可较好模拟出中国大陆夏季高温日数的空间分布特征,但对高温日数的模拟则普遍高估。通过分析观测和模式模拟的日最高温度的概率分布特征,定量评估了日最高温的均值和方差的模拟偏差对模式高估极端高温日数的相对贡献,指出日最高温度均值的模拟偏高是模式高估高温日数的主要原因,但日最高温方差的模拟偏差对高温日数的高估也有重要影响,以江淮地区8月份为例,其贡献可达22%。进一步分析表明,IAP模式未能模拟出江淮流域1980s年代前后极端高温日数的年代际减少,主要归因于模式未能模拟出1980s前后日最高气温均值的年代际减小,而模式未能模拟出日最高温方差的年代际减弱也起很大作用。

关 键 词：Hot days variance inprobability distribution bias attribution modelevaluation IAP AGCM 

分 类 号：P434[天文地球—大气科学及气象学]