The Characteristics Of Potential Climate Productivity Of Grassland And Prediction Research From 1959 To 2008 In Gansu, Qinghai And Xinjiang

Based on the observed data of monthly temperature and precipitation of 106 weather stations from 1959 to 2008 in Gansu, Qinghai and Xinjiang, characteristics of the temporal and spatial of the potential productivity of grassland are analyzed with methods of the linear trend, Miami and Tharnthwaite Memorial model, ArcGIS. Predict the future potential productivity of grassland according to the R/S method and the binary linear regression equations. The main conclusions are as following:1. In the recent 50 years, both the annual temperature and precipitation show a linear increase in Qinghai and Xinjiang, the change rate are respectively 0.309℃/10a, 0.34℃/10a, 4.479mm/10a and 6.77mm/10a. The change rate of annual temperature is 0.297℃/10a in Gansu, while the precipitation has a distinctly decreasing tendency,with a speed of -3.574mm/10a.2. In the recent 50 year, the temperature potential productivity of grassland appear obvious increasing tendency by linear trend in study area. The precipitation and evapotranspiration potential productivity of grassland in Qinghai and Xinjiang also show the increasing tendency, but they come to decrease in Gansu. In spring, summer and autumn, also in growth season the temperature, precipitation and evapotranspiration potential productivity of grassland change tendency is consistent with the annual variation tendency.3. Through contrast and correlation analysis, it shows the linear correlation basically between the potential productivity of grassland and precipitation in Gansu, Qinghai and Xinjiang. The smallest correlation coefficient reaches as high as 0.861 (α=0.001), but the biggest correlation coefficient is only 0.598 between the potential productivity of grassland and temperature. Obviously, the dominant factor of grassland production potential in the study area is moisture condition.4. In recent 50 years, the precipitation mostly assumes increasing in study area, the region to be few, mainly in Gansu. The average annual precipitation performed the middle part is the fewest,and increase to either south or north. The potential productivity of grassland change tendency is consistent with the precipitation, the increased area mainly in Xinjiang and Qinghai. In the decreasing area, Gansu accounts for the proportion to reach as high as 76.92%. The potential productivity of grassland is also increases from the middle to south and north.5. By the R/S method, the temperature, precipitation and the potential productivity of grassland will continue present's change tendency in the future. By establishing a binary linear regression equation, the temperature, precipitation and evapotranspiration potential productivity of grassland in the three regions all present the proportional relations. The potential productivity of grassland will decrease 19.597kg/(hm~2·a) every 10 years in Gansu, while in Qinghai and Xinjiang, it will increase 106.863kg/(hm~2/·a) and 170.601kg/(hm~2/·a) every 10 years.