MERRA再分析地面气温产品在青藏高原的适用性分析  

Applicability Analysis of MERRA Surface Air Temperature over the Qinghai-Xizang Plateau

作　　者：除多[1,2] 杨勇[3] 罗布坚参 边巴次仁[2] 

机构地区：[1]中国气象局成都高原气象研究所拉萨分部,拉萨850000 [2]西藏高原大气环境科学研究所,拉萨850000 [3]西藏自治区气候中心,拉萨850000 [4]西藏自治区气象台,拉萨850000

出　　处：《高原气象》2016年第2期337-350,共14页Plateau Meteorology

基　　金：公益性行业(气象)科研专项(GYHY201206040);国家自然科学基金项目(41561017)

摘　　要：利用1981-2010年青藏高原60个气象站地面观测气温对MERRA再分析资料地面气温产品T2m进行了评估检验和适用性分析。结果表明:(1)MERRA T2m在青藏高原存在系统性偏低,平均偏低3.2℃,地势相对平坦、地表类型较为单一的高原内陆和北部MERRA T2m更为接近实测气温,而地形和地表类型复杂的高原东南部和南部河谷地区MERRA T2m偏差较大,但是在气温的长期变化趋势上与实测气温具有较好的一致性,MERRA T2m年平均气温升幅要小于实测气温升幅(0.18℃·(10a)^(-1));(2)MERRA T2m与观测气温之间具有较好的线性相关关系,平均相关系数为0.76,96.7%的气象站点通过了P<0.05的显著性检验,85%的站点则通过了P<0.001显著性检验,相关程度相对较低的站点位于纬度较高的高原北部;(3)MERRA T2m产品相比其他全球再分析资料在青藏高原地面气温表达方面具有一定的优势,是弥补青藏高原观测台站不足,开展高原气候变化、能量平衡和水循环研究以及选取区域气候模式初始场的较好再分析资料。Atmospheric reanalyses integrate a variety of observing systems with numerical models to produce a temporally and spatially consistent synthesis of data for weather and climate variability studies. Products provided by reanalyises are the objectively analyzed fields over the globe,including regions with minimal observations,and also for fields that are rarely or never observed. In order to evaluate the applicability of MERRA products over the Qinghai-Xizang Plateau（QXP）MERRA reanalysis surface air temperature product T2m with surface observation air temperature from 60 meteorological stations over 30 years from 1981 to 2010 were compared for the seasonal variations and long tern trends of temperature over the QXP. Main results are as follows：（1）MERRA T2m shows very high correlation with observation temperature with a correlation coefficient of0. 76 on average,in which 96. 7% of the total stations is significant at the 95% level and 85. 0% of the total stations is significant at the 99. 9% level. The correlation in winter is better than that in summer. The relatively low correlation coefficients are found at higher latitude regions of northern QXP.（2）MERRA T2m is lower than the in-situ observations in most of stations on the QXP with lower 3. 2 ℃ on average,and is more close to observation temperature in relatively flat terrain and homogeneous surface features in interior and northern region of the QXP while higher bias is found in complex terrain and surface features in the southeastern and southern mountain and river valleys where land – atmosphere interactions strongly affect the physical parameterizations in the numerical models and complex terrain and heterogeneous surface features as well as persistent cloud cover may contribute to these differences. MERRA T2m standard deviation is smaller than observed as well. However,for long term trends the increase in observation temperature（0. 525 ℃·（10a）^（-1））is well represented by MERRA（0. 342 ℃·（10a）^（-1））though MERRA

关 键 词：青藏高原 MERRA 地面气温 适用性分析 

分 类 号：P468.021[天文地球—大气科学及气象学]