NCAR分析资料在大气边界层内误差的初步分析

通过比较1998年南海季风试验(SCSMEX)期间(1998年5月5日～5月25日,6月4日～6月20日)7个站点的探空加密观测资料与NCAR分析资料,分析了在大气边界层内分析资料存在的误差.结果表明:在大气边界层内,NCAR分析资料存在较大的误差.位温和比湿误差随着高度的增加呈现下高上低的特征.比湿的误差要大于位温的误差,7个站点的位温均方差最小值基本都小于1 K,最大均方差也不大于2 K,而比湿均方差最小值基本都大于1.0 g·kg~(-1),部分站点的误差最大值超过2.0 g·kg~(-1).初步说明,下垫面对NCAR分析资料误差的产生有较大影响,内陆地区和海岛地区的分析资料位温的误差比沿海地区大,而比湿数据则相反;在垂直方向上,分析资料的位温误差在0.98～1.33 K之间,比湿误差介于1.39～1.60 g·kg~(-1)之间.

Preliminary Error Analysis of the NCAR Analysis Datasets in the Atmospheric Boundary Layer

Some comparative analysis of the seven stations sounding data during the South China Sea Monsoon Ex-periment(SCSMEX)in 1998 and NCAR analysis datasets(during 5-25 May 1998 and 5-25 June 1998)within the atmospheric boundary layer.The results show that:In the atmospheric boundary layer,NCAR analysis datasets have a big error.The error of the potential temperature and specific humidity of the andysis dataset decrease with el-evation;the error of the specific humidity is bigger than the error of the potential temperature with the analysis data-sets,basically,the square deviation of the potential temperature are less than 1 K at the seven stations,the greatest square deviation is not more than 2 K.while the square deviation of the specific humidity are greater than 1.0 g·kg~(-1),the greatest error are more than 2.0 g·Kg~(-1) at some stations;preliminarily,it can illuminate that the differ-ent underlying surfaces lead to a relatively large impact on the error of the NCAR analysis datasets,the potential temperature of the analysis datasets are not precise in inlands and islands than the values of the littorals,on the con-trary,the specific humidity is precise in inlands and islands than the values of the littorals;in the vertical direction,the range of the potential temperature square deviation is 0.98-1.33 K,and the range of the specific humidity square deviation is 1.39-1.60 g·kg~(-1).