The Homogeneity Test And Adjustment To Chinese Precipitation And Humidity Of The Last 50 Years

As the trend of global warming more and more obvious, the climatal changeresearch is becoming the most concerned problem. Long homogeneous data is thebasis of climatal change research. A homogenous time serial means a serial that onlyincludes weather change and climatal change. The moving of stations, changing ofequipment and the variety of observation rules result in the inhomogeneity od dataseries. These inhomogeneious climatal series influence the improvement of qualityand standard of climatical operation and climatical research.In this paper, monthly precipitation and humidity dataset are used. North test andSNHT are used here to analyze the inhomogeniity of precipitation and humidity andmake adjustment to these inhomogeneious series using SNHT. Main results areconcluded as follows:1. Homogeneious test is used to monthly precipitation and humidity dataset whichis more than 20 years. The result show that only 4％of stations' precipitationseries is inhomogeneious and about 48.8％of humidity stations isinhomogeneious.2. The adjust value of yearly precipitation series is between -3％～-7％, which isconsistent with the summer monthly precipitation. The reason is that precipitationin summer is more than winter. The yearly humidity series adjust value tl isbetween -5.38～4.76, and 47.3％is below zero. 3. The correlation of tested stations and reference stations is not very high. Themain problem of the difficult to inhomogeneious adjustment is the poorprecipitation station density. Humidity stations' correlation is better thanprecipitation, but there is still 7.3％of stations failed to be tested, and the poordensity is still the main problem.4. According to the analysis of 613 stations linear trend between 1970 and 2000, theyearly relative humidity has obvious positive and negative changes, and most ofthe stations are negative. The negative trend reached 5％confidence is 56.60％before corrected and 54.93％after. In the northeast of china and Neimeng arenegative, while the Yangzi River and west of china are positive. The positivetrend reached 5％confidence is mainly in the southeast of Tibet and Xinjiang,and the area becomes larger after corrected. The negative trend reached 5％confidence is mainly along the seaside of Guangxi and Guangdong, and the areabecomes smaller. The negative trend of the seaside of Jiangsu and Shandongbecomes smaller and the positive trend in the north of Xinjiang becomes smaller,the new data is more believable.