Merge on daily temperature data by adjusting two series of adjacent meteorological stations with observation type alternation
类型变更的相邻气象观测站的日气温资料整合

Based on the daily temperature records from adjacent meteorological observation stations with observation type alternation from the period 1951-2010,we analyzed the discontinuity and inhomogeneity of their observed meteorological data,and presented an approach to merge these discontinuous meteorological data from these stations.The results could be concluded as follows.(1) The discontinuity of meteorological records caused by the alternation of observation stations would lead to the inhomogeneity of meteorological data and misunderstandings in climate change study.The estimated difference of variation trends in the mean air temperature in January during the past 60 years can reach as high as 6% whether we take into consideration temperature data of stations whose type changed after 1980.(2) Although elevation gradient has significant effects on the daily temperature between adjacent stations,differences in circumjacent environments and underlying surfaces such as rural and urban regions show greater impacts which could lead to an error of over 0.50℃ in monthly mean air temperature between two stations located closely to each other.(3) The adjustment of daily temperature based on difference analysis of observed monthly mean air temperature between adjacent stations can eliminate the inhomogeneity caused by the differences in circumjacent environments,underlying surfaces and elevation gradient.Adjusted temperature series could reflect the actual interannual variability of climate and serve as a set of reliable basic data for the ongoing studies on climate regionalization in China,the impact on climate regionalization from recent climate changes,and the variation of environmental patterns during the cold and warm periods.