Climate Change Of Shiyang River Basin And Its Influence On Agricultural Production Of Rain-fed Agriculture Areas

The Shiyang River Basin is located in Northesat edge, Qinghai-Tibet plateau and the regional climate system is complex because many kinds of climate systems have a lot of influence on it. So, climate change research of this region was significance. Rapid climate change on agriculture is particularly significant, especially in Rain-fed Agriculture areas of agricultural production is more significant.Using climate data from 1959 to 2008 of Shiyang River Basin from 5 weather stations. The trend of climate was analyzed by climatic liner trend and Mann-Kendall trend methods. Then abrupt,periods,and spatial distribution of climate were analyzed respectively by the Mann-Kendall abrupt analysis,the wavelet analysis and GIS. At last, analysis of Climate Warming on Rain-fed Agricultural areas of agricultural production.The main findings can be summarized as follows:(1)Shiyang River Basin average sunshine was an increasing trend. To increase the number of the main spring sunshine and winter and summer at least. The abrupt time is 1963a. After 1983a the rate of sunshine hours are further increasing. The periods of 25a of sunshine hours is the most significant. The distribution is characterized by sunshine: Long duration of sunshine in northern and southern mountain sunshine time is short, Central Corridor plain sunshine and latitude roughly parallel contour. Dark island effect to some extent, affected the city sunshine duration changes.(2)The temperature of River is warming in recent 50a. Climatic trend rate is 0.321℃/10a. Middle and lower reaches of the temperature were much higher than the upstream. The temperature is lower in 20th century of 60-80, 90 years of the 20th century and early 21st century is mostly positive temperature anomalies. Mainly in the winter warming, mainly from the contribution of the lowest temperatures. The abrupt time is 1996a, which from low to high temperature warming. There is change in temperature cycle of about 12a. Temperature distribution is high temperature in northern and the low temperature in southern, the difference in temperature is from south to north into small units. Urban heat island effect on the temperature has a great influence.≥0℃accumulated temperature and≥10℃accumulated temperature were increasing trend in Gulang station from 1971a to 2007a. The abrupt time of≥0℃accumulated temperature was 1991a and 1992a, and it had 14a periods. Abrupt change of≥10℃accumulated temperature was 1989a, and it had 14a and 8a periods. (3)Mean annual of precipitation in Shiyang River Basin is 247.53mm in recent 50a, climatic trend rate of annual precipitation for every 10 year was 7.3mm. So there was wet trend in study area. The abrupt of annual precipitation was not obvious. The periods of 13a is the first cycle. The spatial distribution of precipitation is similar to the sunshine, Precipitation of the southern mountain areas was more than in the northern. Island effect rain did not affect the city of precipitation increases.(4)There was a decreasing trend of wind speed in Shiyang River Basin in recent 50a, no other than the upriver of Wushaoling station was an increasing trend .The lowest wind speed in the 60 years, from 90 years to so far wind speed is 3m/s. Spring,autumn and winter wind speed is gradually decreasing, but in summer there was a increasing trend which rate was 0.004m/(s·10a). In 1988a occurred in high to low abrupt. Wind speed had 19a periods. High values mainly in the south of the mountain and low values in the north of Wuwei areas.(5)Rain-fed Agriculture areas of Shiyang River Basin had the distinct warming trend, heat resources had increased, suitable for growing thermophilic crops, the scope of thermophilic crops were expanding, spring wheat acreage were reduction, which led to significant changes in the structure of summer and autumn crops. Due to climate warming, growth period of spring wheat was shorter nearly two days, 5-9 days before sow period.(6)Grassland area was severely degraded because of the climate change. The pasture growth is lack of heat conditions but the moisture conditions were adequate, heat is the main factor which limited pasture growth. Sunshine and wind speed play a role in weakening grassland climate productivity, climate yield increases with the precipitation. The increase of temperature play the role to promoting the increase of the climate output.