中国探空位势高度资料的非均一性检验与订正

Inhomogeneity Test and Correction of China Radiosonde Geopotential Height Data

利用加拿大环境部气候研究中心研发的PMFT均一化检验方法,结合国家气象信息中心整理的中国区域各探空台站元数据信息,对我国123个探空台站各标准等压面月平均探空位势高度资料进行了非均一性检验和订正。结果表明:仪器换型、探测系统升级以及辐射订正方法改变是造成中国区域月平均探空位势高度资料不均一的主要原因。两个观测时次位势高度序列不均一的台站数随高度的增加而增加。各标准等压面上月平均位势高度序列不均一的探空台站平均订正幅度也随着位势高度的升高而增大。并且两个观测时次各标准等压面位势高度序列均为负订正,表明我国各标准等压面位势高度资料存在系统性偏高的问题。123个探空台站在对流层顶和对流层高层位势高度序列订正前是位势高度降低趋势,订正后位势高度序列呈增高趋势。对流层中低层原始位势高度序列呈增高趋势,订正后这种增高趋势更加明显。

Using the PMFT method developed by Environment Canada and the metadata collected by National Meteorological Information Centre of China Meteorological Administration, the inhomogeneity test and corrections are carried out to the monthly geopotential height data of 123 radiosonde stations in China. The result shows that shifts of instruments, update of sounding systems and change of radiation correction method are the main causes for the inhomogeneity in the regional sounding geopotential height data in China. With the height increasing, both the number of the inhomogeneous stations in two observation time and the mean magnitude of correction increase significantly. The correction values are negative at all mandatory levels, which indicates the radiosonde geopotential height data in China is higher systematically. The raw monthly mean geopotential height series of the 123 radiosonde stations in the tropopause and the higher levels of troposphere present decreasing trends, after correction, the trends change to increasing trends. In the middle and lower levels of the troposphere, the increasing trend of the geopotential height becomes more obvious after the correction.