The Main Agricultural Meteorological Disasters And The Evolution Of Main Grain Yield In Shaanxi Area Under The Background Of Climate Change

Climate change and disastrous weather have important effects on agricultural production.Shaanxi province which is located in the hinterland of China,is an important grain production base in China,the study of climate change on food production in Shaanxi area is of great significance for food security.Based on 84 meteorological stations meteorological observation data from 1980 to 2010,we first analyzes air temperature,precipitation and sunshine characteristics and change characteristics in three areas including Northern Shaanxi,Guanzhong and southern;then analyzed the characteristics change of drought,floods,hail and frost and other weather disasters from 1980 to 2010 in Shaanxi area and its effects on wheat and corn production.On this basis,taking winter wheat as an example,by using the trend analysis we analyzes agricultural climate resources distribution of winter wheat growing period in Shaanxi.The main conclusions of this paper are as follows:(1)Statistical analysis that the routine observation of meteorological elements showed that the annual average temperature of three regions in Shaanxi province included Northern Shaanxi,Guanzhong and southern Shaanxi were showing a rising trend whithin 31 years from 1980 to 2010.The warming trend in Northern Shaanxi was the most significant which was much higher than that in Guanzhong and southern Shaanxi.The average annual precipitation anomaly dropped in Shaanxi area was declining by ways of range in ways of wave type,distribution and variation trend of precipitation with regional characteristics were obvious.The change range of precipitation in Northern Shaanxi area was more significant than that in Guanzhong and southern Shaanxi.Research on sunshine duration in Shaanxi showed that average summer sunshine hours in Shaanxi area was the most,winter sunshine hours was the least,sunshine hours in spring and autumn were in between.The change trend of sunshine hours in northern Shaanxi was less than that in Guanzhong and southern Shaanxi.(2)The main meteorological disasters including drought,floods,hail and frost and the rate of agricultural production and the hazard rate analysis in Shaanxi Province shows that drought disaster rate and hazard rate in the early 90 s of the 20 th century appeared an obvious turning point,from the 1990 till 2010,drought disaster rate change was significant,the frequency increased obviously in exceptional drought at the same time.Flood disaster rate and hazard rate in Shaanxi province declined slightly,but the varied in a wide range.The change trend of Shaanxi hail disaster rate and hazard rate was almost the same,before 1990 the disaster rate and the hazard rate were rising in an obviously trend;During the period of 1990 to 2005,the disaster rate and the hazard rate fluctuated widely;The rate after 2005 and the trend of disaster rate and hazard rate were reduced.Frost hazard rate rised significantly,so do the hazard rate.(3)The data of winter wheat planting and growing period in Shaanxi Province from 1980 to 2010 show that due to the gradually increasing temperature in Shaanxi,the winter wheat sowing temperature was generally increased and the effectively accumulated temperature was increased significantly which caused the heat condition in winter wheat planting area was enhanced before overwintering;0 ? all day hours in 1980 s to 90 s at the beginning fluctuated a lot,after 90 s was in a postponed trend,0 ? all day hours in Guanzhong delayed for 0.2~0,6 a day in annual average,the change in Shannan area was not obvious,which cause the date of winter wheat overwintering in south and Shaanxi and Guanzhong was delayed,wheat growing period prolonged 4~8 days before the winter;growth and development period of winter wheat after winter was general in advance,the regreening stage of Winter Wheat in Guanzhong area was ahead of schedule to mid February,early jointing stage ahead to late March,Spike period ahead to late April,the milky stage and mature period were also in advance.(4)Analysis of wheat and corn production in Shaanxi Province from 1980 to 2010 showed that the production of wheat rarely fluctuated in this area and corn production was in an increasing trend.