| Agricultural stability is critical to the sustainable development of a country,Agriculture is one of the most sensitive areas of climate change,Shanxi,Shaanxi and Inner Mongolia is an important geographical transition area in China,The agricultural development is more affected by climate change in Shanxi.Shaanxi and Inner Mongolia.The daily mean temperature,daily minimum temperature,monthly precipitation,monthly sunshine hours,monthly average temperature,hottest month and coldest monthly mean temperature were analyzed by using the linear trend line method,Mann-Kendall mutation test,wavelet analysis and spatial analysis of ArcGIS based on meteorological observed data from 75 meteorological stations in Shanxi and Shaanxi and Inner Mongolia from 1960 to 2015.The main conclusions showed that:(1)Accumulated temperature>0?(ATO),accumulated temperature>10 ?(AT10)showed an increasing trend,the increasing rates were 76.03?·d·10a-l?73.32?C.d.d lOa-1.In the age of accumulated temperature,AT0,AT10 is the largest in 2000s and the smallest in 1960s.ATO and AT 10 mutated in 1992 year in Shanxi and Shaanxi and Inner Mongolia.From the spatial distribution.ATO and AT 10 in the whole region decreased with latitude increasing and altitude increasing,temperature tendency value of ATO and AT 10 is high in low latitude and high altitude area,temperature tendency value of ATO and AT 10 is low in high latitude,low altitude area.(2)The number of days of ATO and AT 10 are increasing during 1960?2015 years in Shanxi and Shaanxi and Inner Mongolia,the rate of increasing were 2.77d/10a?2.74d/10a.The increasing rate of the number of days of ATO were 3.25 d/lOa.3.08 d/1Oa.2.83 d/lOa in Shaanxi,Shanxi,Inner Mongolia.The increasing rate of the number of days of AT10 were 3.38d/10a.3.94 d/10a.2.16 d/lOa in Shaanxi,Shanxi,Inner Mongolia.The increasing rate of the number of days of ATO and AT 10 passed the significant level test of 0.01.The number of days of ATO and AT10 was long in low latitude and was short in high latitude,the number of days of ATO and AT1O was increasing in the whole region,the increasing trend of the number of days of ATO and AT 10 was high in the low latitude and high altitude,was small in the high latitude.The first day of ATO and AT 10 arrived in advance,there are differences in the rate of advance in different regions.The last day of ATO and AT10 arrived late.(3)The number of frost-free days in the Shanxi,Shaanxi and Inner Mongolia was increasing from 1960 to 2015,and the rate of increase was 3.69 d/10a,which passed the significant level test of 0.01.The increasing rate of frost-free period in Shaanxi Province,Shanxi Province and Inner Mongolia was 2.38 d/10a,3.31 d/10a and 4.22 d/10a.The mutation time of the frost-free period was 1994 in the Shanxi,Shaanxi and Inner Mongolia,which was not significant.The mutation time of the frost-free period was 1989 in Inner Mongolia,which was not significant.The mutation time was 1996 and 2000 in Shaanxi and Shanxi respectively.The first day of frost arrived in late,the last day of frost arrived in advance,and the first day of frost pushed back 9d and the last day of frost arrived ahead of 12d from 1960 to 2015 years.The tendency of first and last day of frost were passed by the significant level test of 0.01 in Shanxi,Shaanxi and Inner Mongolia from 1960 to 2015.The first day of frost respectively pushed back 5d,8d and 1Od in Shanxi,Shaanxi and Inner Mongolia,and the last day of frost respectively arrived ahead of 8d,l1d and 14d.The tendency of the first day of frost in the high latitude was greater than that in the low latitude,the tendency of the last day of frost in the high latitude was greater than that in the low latitude.(3)During the growing season,the precipitation showed a decrease in Shanxi,Shaanxi and Inner Mongolia from 1960 to 2015,the decreasing rate was 3.69mm/10a,the decreasing rate of Shanxi,Shaanxi and Inner Mongolia respectively' was 10.06mm/10a,6.12mm/10a,0.86 mm/1Oa.There were no significant mutations in precipitation during the growing period of Shanxi,Shaanxi and Mongolia.There are two cycles in precipitation during the growth period of Shanxi,Shaanxi and Inner Mongolia,the cycle was 3a and 6-7a,the main cycle is 7a.In areas with low precipitation,the precipitation is increasing;in areas with high precipitation,the precipitation is decreasing.(4)During the growing season,the sunshine hours showed a significant decrease in Shanxi,Shaanxi and Inner Mongolia from 1960 to 2015,the rate of change was-22.29h/10a.The rate of change in sunshine hoiurs were-14.36h/10a,-43.29h/10a,-18.40h/10a in Shaanxi,Shanxi,Inner Mongolia.The rates of variability in sunshine hours were 39%,32%,13%in Shaanxi,Shanxi,Inner Mongolia.During the growing season,the sunshine hours mutated in 1991/1992 in Shanxi,Shaanxi and Inner Mongolia,the sunshine hours mutated 1994/1995 in Shanxi,the sunshine hours mutated in 1986/1987 in Inner Mongolia.During the growing season,there are three obvious oscillatory cycles of the sunshine hours in Shanxi,Shaanxi and Inner Mongolia,the cycle was 27a,10a,3a,the main cycle was 27a.The coefficient of variation of the sunshine hours showed a spatial difference,it decreased from east to west and from south to north.The sunshine hours was characterized by the spatial distribution characteristics of "west high east low,north high south low".(5)The average temperature of hottest month and the coldest month showed an increasing trend,the rising rate were 0.272 ?/10a,0.327 ?/10a.The average temperature of hottest month had two cycle in Shanxi,Shaanxi and Inner Mongolia,the cycle were 11a,5a,the main cycle was 11a;the average temperature of coldest month had two cycle in Shanxi,Shaanxi and Inner Mongolia,the cycle were 8a,3a,the main cycle was 8a.(6)The climate zone extended to the direction of temperature increase in Shanxi,Shaanxi and Inner Mongolia from 1980 to 2015,the northern subtropics showed a tendency to expand around,the warm temperate zone expanded eastward,westward,high latitude and high altitude,The area of medium temperature zone and the cold temperate zone reduced.AT10,frost-free period,sunshine hours,the coldest month temperature and the hottest month temperature had a negative effect on the climate yield of wheat and corn,the precipitation had a positive effect on the climate yield of wheat and corn,there was a significant positive correlation(P<0.05)between climate yield and precipitation in Shanxi,Shaanxi,Inner Mongolia,there was a significant negative correlation between climate yield and hottest month temperature in Shanxi and Shaanxi,there was a significant negative correlation between climate yield and sunshine hours in Inner Mongolia. |
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