Spatiotemporal Changes of Precipitation and Temperature at Water Resources Conservation Forests Area in Qilian Mountains,China

Study on temporal and spatial variations of precipitation and temperature has significant meaning for the establishment of climate change early warming system.In this paper,the meteorology and hydrology automatic monitoring equipments were used to observe precipitation and temperature at the water resources conservation forests area in the Pailugou River basin in Qilian Mountains along the environmental grades and the vegetation types.Results showed that the inter-year precipitation variation in the forest area in Qilian Mountains presented a single peak curve,and it mainly took place in summer which accounting about 72% of the annual precipitation.The precipitation also showed obviously environmental grade difference,and it was the biggest at the arbor and shrub mixture area(3 300 m),and the precipitation increased with the increase of the altitude below 3 300 m but decreased with the increase of the altitude above 3 300 m.As for temporal variation,precipitation decreased before 2004 but increased significantly after 2004.The annual average temperature increased slowly since 1986 in the forest area in Qilian Mountains,and it was below 0 ℃ in the most years,and the smallest was-1.33 ℃.The annual average temperature increased sharply since 2003,and the biggest annual average temperature was 2.5 ℃.The annual average temperature increased by 3.83 ℃during the recent 24 years at the study area.Because of air temperature increase,the soil temperature increased rapidly,especially in the top and deep soil,and the conclusion was basically the same with other observation results.