| The change of surface radiation balance condition reflects the climate change.The research on radiation and energy balance process and the change of related environmental factors has important significance to objectively measure the climate condition and predict future climate change.Qinhuai area is an important geographical demarcation zone about China.Studying on the surface radiation budget of this area can explore the regional climate change characteristics under the background of global climate change.Base on the CERES(the Clouds and the Earth's Radiant Energy System)data,the paper analyzed the temporal and spatial variation of land surface radiation budget in Qinhuai area.Then combined with the cloud radiative forcing,Vegetation Coverage and El Nino index,using statistical methods,the relationship between the spatial and temporal variation of surface radiation budget and this three factors were analyzed.Finally,the following conclusions can be achieved:(1)The characteristics of shortwave radiation flux in Qinhuai area are as follows:(1)The multi-year mean of downward shortwave radiation flux was 140.88 W·m-2,which had experienced three decline period(2001-2004/2007-2011/2013-2015)and three increased period(2000-2001/2004-2007/2011-2013);While the multi-year mean of upward shortwave radiation flux was 18.59 W·m-2,which had experienced a trend of decline(2000-2003)-rise(2003-2013)-decline(2013-2015)three stages.(2)On the amplitude of seasonal variation,the downward shortwave were showed that the autumn is the maximum and summer is the minimum;While the upward shortwave showed that spring is the maximum and autumn is the minimum.(3)In terms of the amplitude in monthly scale: February is most,the downward shortwave of March is minimum and the upward shortwave of June is minimum.there was some mutations of downward shortwave happened in July during 2002 while upward shortwave happened in July,September and December during 2002,2004,2004.(4)In terms of space,the downward shortwave presents a heterogeneity between northwest and southeast,the provinces of Sichuan,Gansu,Shaanxi,Henan were rosen,of which the provinces of Anhui,Jiangsu and other provinces were decreased;while the upward shortwave presents a heterogeneity between north and south,of which the provinces of Shaanxi,Henan,Shandong,Anhui and the northern of Jiangsu showed an upward trend,and the province of Chongqing and Hubei showed a downward trend.(2)The characteristics of longwave radiation flux in Qinhuai area are as follows:(1)The multi-year mean of upward longwave radiation flux was 393.49W·m-2,which had experienced twice decline(2000-2002/2007-2012)-rise(2002-2007/2012-2015)changes;While the multi-year mean of downward longwave radiation flux was 349W·m-2,and take the year of 2008 as a boundary,before that is a downward trend and after that is an upward trend.(2)On the amplitude of seasonal variation: the upward longwave showed that the spring is the maximum and summer is the minimum;while the downward longwave showed that winter is the maximum and summer is the minimum,there were some mutations of the upward longwave happened in summer of 2004.there were some mutations of the downward longwave happened in winter of 2002.(3)In terms of the amplitude in monthly scale: February is the most,the minimum of the upward longwave is in September and the minimum of downward longwave is June.There were some mutations of upward longwave happened in Auguest during 2006 while downward longwave happened in April,July,and November during 2004,2014,2006.(4)In terms of space,the upward longwave presents a heterogeneity between west and east,the provinces of Gansu,Shaanxi,Sichuan showed an upward trend,while the provinces of Shandong and Anhui showed a downward trend;And there was only a small rise of the downward longwave in the province of Chongqing and Gansu.(3)The correlation between Qinhuai area radiation budget components and cloud radiative forcing,Vegetation Coverage,El Nino shows that:(1)The effect of cloud on the downward shortwave radiation is significant,and the enhancement effect of the long wave radiation flux is not obvious.(2)The influence of vegetation cover on the upward radiation flux is not significant,but the influence of atmospheric composition on the radiation flux is greater than that of the surface cover.(3)in terms of temporal,the shortwave radiation flux in March,May has a significant negative correlation to El Nino;The longwave radiation flux in July and August has a significant negative correlation.in terms of spatial distribution,When the El Nino event occurred,the radiation budget components of the study area showed the spatial heterogeneity between the west,North and central and south. |
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