再分析资料中可降水量与地面水汽压关系检验(英文)

Validation of the Relationship between Precipitable Water and Surface Vapor Pressure by Means of Reanalysis Data

利用ERA-40、JRA-25、NCEP/NCNR、NCEP/DOE4种再分析资料,计算了各种时空尺度的可降水量(W)与地面水汽压(e)关系式,通过对比不同资料W-e关系式,验证再分析资料可降水量数据的可信度,为其应用提供依据和参考。结果表明,①在中国区域内,ERA-40再分析资料W-e关系式与探空资料W-e关系式最接近,ERA-40再分析资料可降水量数据可信度高于其他再分析资料。②对比全球范围内4种再分析资料W-e关系式发现,年平均W-e关系式在中纬度地区差异较小,低纬度和高纬度地区差异较大;季节平均W-e关系式在北半球中纬度地区春、秋、冬三季差异较小,夏季差异较大。因此北半球中纬度地区春、秋、冬三季,再分析资料可降水量数据可信度较高,其他区域和季节可降水量数据可信度较低。③不同年份间,NCEP/NCNR、NCEP/DOE再分析资料W-e关系式稳定性较好,而ERA-40、JRA-25再分析资料W-e关系式稳定性较差。

By means of ERA-40, JRA-25, NCEP/NCAR and NCEP/DOE reanalysis data, empirical relations between precipitable water and surface vapor pressure in spatial and temporal scale were calculated. The reliabilities of precipitable water from reanalysis data were validated based on comparing different W-e empirical relations of various reanalysis data, in order to provide basis and reference for reasonable application. The results showed that W-e empirical relation of ERA-40 was closest to that of sounding data in China, and precipitable water from ERA-40 was the most credible. The worldwide comparison among W-e empirical relations of four reanalysis data showed that there was little difference in annual mean W-e empirical relations in the middle latitudes and great differences in low and high latitudes. Seasonal mean W-e empirical relations in the middle latitudes of the northern Hemisphere had little difference in spring, autumn and winter, but great difference in summer. Therefore, the reliabilities of precipitable water from reanalysis data in spring, autumn and winter in the middle latitudes of the northern hemisphere were higher than other areas and seasons. W-e empirical relations of NCEP/NCAR and NCEP/DOE had good stability in different years, while there was poor stability in ERA-40 and JRA-25.