自动气象站温湿度传感器更换的影响评估

Impact Evaluation for Replacement of Temperature-humidity Sensor of Automatic Weather Station

选取湖北省自动观测记录较长的38个站作为被检站,每个被检站选取3个邻近站,统计相对湿度、水汽压序列与邻近站的相关系数、平均值及方差变化情况,分析由人工观测改变为自动气象站观测后,两者存在的差异,并对其中4个国家基准气候站2003—2011年自动观测和同期人工观测进行对比,得到这4个站9年内每次更换温湿度传感器对相对湿度、水汽压记录的影响情况。结果表明:对比自动观测与人工观测两个序列,被检站与对应邻近站的相对湿度、水汽压的相关系数呈减小趋势,两种观测差值的平均值和方差差异显著;温湿度传感器的更换易产生相对湿度和水汽压记录的跳变;温湿度传感器的检定示值误差是加剧自动观测与人工观测序列显著差异的重要因素;改进观测方法,完善自动气象站检定规程,是自动观测与人工观测序列均一性的重要保证。

To discuss the differences between automatic and manual observations for relative humidity and water vapor pressure, some comparative researches are implemented, analyzing the correlation coefficient, mean and variance between 38 long time automatic observation meteorological stations and their adjacent stations in Hubei Province. Furthermore, based on the automatic and manual observations of four national reference climatological stations where the temperature humidity sensors have been replaced 28 times from 2003 to 2011, impacts on relative humidity and water vapor pressure measurements are studied. The correlation coefficients for relative humidity, water vapor pressure between the checked station and its adjacent stations show a decreasing trend when mannual observation is replaced by automatic observation, the mean and variance for relative humidity and water vapour pressure are also obviously different, and these differences may be caused by the change of observation method.The relative humidity and water vapour pressure records jump caused by replacement of the temperature humidity sensor appears in the ratio of 64%. The average relative humidity record jump is 3.4%, and the maximum reaches 8.5%, while the average for water vapor pressure is 0.74 hPa, and the maximum is up to 1.93 hPa. The main cause for such difference appearing at the same station as described above is that calibration error of indication, for old temperature humidity sensor is much different from the new one when replacing. So improving the method of observation and perfecting the verification procedure of automatic weather station are vary important to ensure the homogeneity of data.Therefore, it suggests choosing the temperature humidity sensor whose calibration error is smaller, and an error calibration module should be added to the data processing software or operational software of automatic weather stations.