Temporal-spatial Characterization Of Atmospheric Environment And Climatic Resources Over The Yunnan-Guizhou Plateau

Yunnan-Guizhou Plateau(YGP) is situated in Southwest China with elevation between 400m and 3500m and north-south and northeast-southwest mountains in China.In contrast to central and eastern China, the atmospheric environment and climatic variations on the YGP,a remote region in Southwest China are required to further studied.a 31-year data set of meteorological observation data、population and energy consumption within the provinces of Yunnan and Guizhou from 1980 to 2010 were used in this analysis, we studied climate changes and atmospheric environment including visibility and haze over the YGP and climate resources changes in Guizhou Province to comprehensively understand the relationship between the atmospheric environment changes and regional climate changes on the YGP.The main and findings are as follows:(1)The climate change of the YGP:1)The YGP is a typical region of subtropical monsoon in the upland,on the average, the annual mean temperature over the YGP was higher in its southern part than its northern part, the maximum and the minimum respectively existed in its southwestern part and northwestern part, and the annual mean temperature on most area of the YGP varied from 11℃ to 23℃.The distribution of annual mean wind speed over the YGP were stronger in its central and northwestern part than its eastern and western part, the downward trend of wind speed was in good agreement with the altitude falling trend over the YGP, as the weak wind area in China, the annual mean wind speed over the low altitude area of the YGP varied from 0.6m/s to 1.1m/s.The distribution of precipitation over the YGP was of a large spatial variation and the precipitation over the YGP was more in its southwestern and southeastern part than its central and northern part, annual precipitation over the YGP varied from 500mm to 2100mm.The annual sunshine duration on the YGP given the overall sloping topography of the YGP from west to east, the annual sunshine duration over the most area of the YGP varied from 1000 hours to 2600 hours and its eastern part belonged to the less sunshine duration areas of China.2)Temperature、precipitation、wind speed and sunshine duration over the YGP all seem to be of obviously seasonal variation.Relative to other areas of China, the climate over the YGP was not cold in winter and not hot in summer,suggesting the temperature on the YGP was good for our health. The YGP climatology of precipitation was directly connected to the East Asian monsoon and South Asian monsoon,forming the distinct regional seasonal precipitation over the YGP which was dry in winter and wet in summer.The wind speed and sunshine duration over the YGP all had significant seasonal variations with the maximums in spring and the minimums in autumn,and the seasonal mean values of wind speed and sunshine duration over the YGP in summer were all less than in winter.3)Taking the YGP as a whole5the temperature over the YGP had obvious changes from year 1980 to 2010,the annual、spring、 summmer、autumn and winter mean temperature all increased over the YGP during the same time with the trends of 0.28℃、0.34℃、0.1℃、0.23℃ and 0.47℃ per decade;The interannual variation in wind speed over the YGP were indistinct,the decreasing trends in annual、spring、 summer and winter mean wind speed had the negative values reaching -0.04m/s、-0.1m/s、-0.03m/s and -0.04m/s per dacade,the increasing trend in autumn mean wind speed inversely reached 0.01m/s per dacade;The annual precipitation and sunshine duration over YGP were both found to have negative trends, seasonal precipitation over the YGP experienced positive trends while and sunshine duration experienced negative trends in spring and summer,this phenomenon was inversely confirmed by the decreasing trends in seasonal precipitation and the increasing trends in sunshine duration over the YGP in autumn and winter.(2)The variations of Atmospheric environment were characterized by dry visibility over the YGP:After a 31-year data set of visibility observed at 204 weather stations over the YGP from year 1980 to 2010 being corrected by humidity,we studied the tempor-spatial characterization of dry visibility over the YGP to show the variation of atmosphere environment over the YGP,the result showed that 1)The annual and seasonal mean dry visibility on the YGP decreased from west to east,the maximum and minimum value respectively existed in its northwestern part and northeastern part.Taking the YGP as a whole.the annual、spring、summer、 autumn and winter mean dry visibility of the YGP were 30.3km,29.4km,33.7km,30.2km, 27.9km;In contrast to other areas of China,there was a good atmosphere environment on the remote YGP. It was found that,the atmosphere environment on the YGP over recent 31 year period was gradually getting worse,the annual、spring、summer、autumn and winter mean dry visibility of the YGP were decreasing with the negative values reaching-1.52km、-0.94km、-2.29km、-1.98km and -0.89km per dacade.2)For annual mean dry visibility of city over the YGP,its change rate of Yunnan Province in the western YGP was less than Guizhou Province in the eastern YGP.The annua、spring、summer、autumn、winter mean dry visibility of country in Yunnan and Guizhou Province all experienced negative trends,the annual、spring、summer and autumn mean visibility of country in Yunnan Province decreased less than Guizhou Province,this relationship was inversely confirmed by decreasing trends in winter mean visibility in country in Yunnan and Guizhou Province with the negative trends reaching-1.43km and-1.18km per decade.3)The atmospheric environment over the YGP was expected to be of a large spatial variation due to the differences in geographic altitude, on the average, dry visibility had positive trends as altitude increased over the Yunnan-Guizhou Plateau with the change rate of 5.1km per 1 km.Taking the YGP as a whole.the annual change of dry visibility was found to be in good agreement with wind speed over the YGP,on the contry,the annual change of dry visibility showed a bad agreement with air temperature、energy consumption and population over the YGP.As a result, the atmospheric environment across the YGP was on the conference of climatological variation and atmospheric pollution over the YGP.(3)The characterization of haze wealther over the YGP:Based on 31 years(from 1980 to 2010) available visibility and relativity humidity data from 202 meteorological stations over the YGP,the characteristics and changes of temporal and spatial distribution of haze days across the YGP were analyzed,the results showe d that 1)the annual and seasonal mean haze days presented less in western and more in eastern YGP.The atmospheric environment across the northwestern YGP,a high latitude area without haze days,was good.Haze days occured mainly in the northeastern YGP where latitude was low,what’s more, Xishuangbanna,the southwestern YGP,had serious hazy weather in spring,which may resulted from local energy consumption and movement of biomass burning in South Asia.2)Taking the YGP as a whole,the spring、summer、 autumn and winter mean haze days of the YGP were 1.3d,0.2d.0.9d and2.9d, the spring and winter mean haze days were more than the autumn and winter haze days;The annual mean haze days of the YGP had a increasing trend with the negative value reaching 0.24d/10a.Furthermore.the spring、summer、autumn and winter mean haze days of the YGP were found to vary with the trends of -0.06d/10a、0.09d/10a、0.22d/10a and -0.1d/10a respectively.3)The annua. spring. summer、autumn and winter mean haze days of city in Guizhou and Yunnan Province all experienced the indistinctly positive trends,in contrast to the city,the annual、spring. autumn and winter mean haze days of country in two province all varied less than the city.The monthly mean haze day(from January to December) of city and country in Guizhou and Yunnan Province during three decades(1980-1990,1991-2000,2001-2010) were mainly characterized by positive trends.(4)Variation in agricultural climate resources in Guizhou Province under the environment climate change:By using the observational data of annual sunshine duration,annual average temperature and annual precipitation from 84 meteorological stations in Guizhou Province from 1982 to 2010,this study is focused on the issues including the spatial distributions and temperial variations of annual sunshine duration、annual average temperature、 annual precipitation and agricultural climate resources in Guizhou Province are analyzed,the results indicate that 1)The annual sunshine duration in Guizhou Province varied most in its northern part and changed less in its southern part,the least area areas were mainly in the western Guizhou Province;The regions with the best temperial variation of annual mean temperature were distributed in the western areas of Guizhou Province,and the variation rate of the annual mean temperature in Guizhou Province were found to decrease from west to east;The annual precipitation changed most in the western Guizhou Province and had little change in its eastern part.2)As affected by regional variations in climate and environment,the resource configuration of Shuicheng Country in northern Guizhou Province was fair and had a positive trend;the resource configuration of Dejiang Country in northeastern Guizhou Province was fair and had a negative trend;The resource configuration of Xingren Country in southwestern Guizhou Province was good and had a positive trend;The resource configuration of Rongjiang Country in southeastern Guizhou Province was fair and had a negative trend;The resource configuration of Pingba Country in central Guizhou Province was good and had a negative trend.3)In the region with the good resource configuration over the southwestern、central and eastern edge areas of Guizhou Province,the configuration coefficients had negative trend;In the region with the fair resource configuration over the southern edge and northern areas of Guizhou Province, the configuration coefficients had the negative trends;The regions with poor or very poor resource configuration were situated in the western edge of Guizhou Province, the configuration coefficient had the positive change trends.The regional climate change resulted in the same climate resources allocation in Guizhou Province.