基于昼夜温差序列非均一性的高空温度订正

Adjustment of upper air temperature based on inhomogeneity of day-night temperature difference series

利用中国东部地区75个高空探测站1958—2005年逐日08时和20时资料和元数据信息,采用昼夜温度对比和二相线性回归法,对不同等压面的温度序列进行均一性检测和订正。在此基础上,以最大缺测率30%作为序列取舍标准,对49个探空站订正前后的年平均温度变化趋势进行对比分析。结果表明:探空仪器变化和辐射订正方法改变是造成中国东部地区高空温度序列非均一性的主要原因,1966年前后和2000年前后是两个较为可靠的间断点,且1966年前后的非均一性更突出。非均一性最明显的等压面主要在100 hPa。1958—2005年,500 hPa以下等压面温度的上升趋势较订正前减弱,但200 hPa到50 hPa等压面温度的下降趋势也被削弱,削弱幅度为0.04—0.08℃/10 a。与1958—2005年相比,1979年以来东部地区对流层各层温度增温趋势明显,而平流层底层降温趋势也较为显著,该时段内订正前后温度变化趋势差异较小。

Based on the daily temperature data from 75 radiosonde stations in the eastern China at 08：00 and 20：00 during 1958 to 2005 and the corresponding metadata,homogeneity of temperature at different levels was tested and adjusted using methods of a temperature difference between daytime and nighttime and a two-phase linear regression.The annual trends of the observed and revised temperature at 49 stations were analyzed by selecting data using 30％ maximum missing rate as a standard.The results indicate that inhomogeneity of temperature is caused by changes of radiosonde instrument and radiation correction method in upper level over the eastern China.The credible breakpoints for inhomogeneity occur in 1966 and 2000,especially in 1966.The most obvious inhomogeneity appears at 100 hPa.Compared with the original temperature series,warming trend of temperature below 500 hPa weakens from 1958 to 2005,so is its decreasing trend from 200 hPa to 50 hPa and the ratio is 0.04-0.08 ℃ every decade.Troposphere temperature increases and lower stratosphere temperature decreases significantly since 1979.Therefore,temperature discrepancy of adjusted and original time series during 1979 to 2005 is small compared with that during 1958 to 2005.