我国南方中东部地区地面太阳总辐射变化规律

Variation of Surface Solar Radiation over the Central and East of Southern China

  • 摘要: 为进一步探讨我国地面太阳辐射的变化规律及其原因,选择我国南方中东部地区,利用该区域1961—2007年33个站点的地面太阳总辐射资料,结合云量、大气水汽含量和能见度等观测资料,综合研究该区域地面太阳总辐射的变化规律及其原因。结果表明:1961—1989年,我国南方中东部地区地面太阳总辐射呈下降趋势,之后发生逆转,1995年后其变化趋于缓和,1961—2007年总体呈现变暗—变亮—变缓的趋势。究其原因,该区域云量平均值由峰入谷、云量下降速率由快变慢可能是产生此变化趋势的原因之一;其次,20世纪80年代到21世纪初,气溶胶光学厚度上升趋势减缓,气溶胶地面辐射强迫变化趋于缓和,某些区域甚至出现下降,也导致部分站点地面太阳总辐射由暗变亮。

     

    Abstract: Surface solar radiation is one of most essential variables that influence the climate and environment. Various studies analyzing long-term records of surface radiation measurements suggest a widespread decrease in surface solar radiation between the 1950s and 1980s (global dimming), with a partial recovery more recently at many locations (brightening). To provide reasonable evidence for predicting the future trend of climate changes, the spatial and temporal variation of surface solar radiation and the causes are analyzed comprehensively by using observational solar radiation data together with conventional meteorological data of the central and east of southern China from 1961 to 2007.Solar radiation is obviously declining during 1961—1990 over the central and east of southern China, and a widespread brightening is observed during 1989—1995, but from 1995 to 2007 brightening doesn't persist and the solar radiation tendency tends to moderation. Increase of aerosol may be the main causes of solar radiation from dimming to brightening during 1961—1990, and the difference of cloud cover tendency maybe the main causes of solar radiation dimming.Model simulation shows that in recent 50 years water vapor is rising, which has decreased solar radiation by 0.55 W·m-2 at the beginning of the 21st Century than that of the 1980s, but it is not main cause of solar radiation from dimming to bighting in recent 50 years. A widespread ascending aerosol optical depth (8.8%) is observed from 1980 to 2007, but the tendency tends to moderation. Due to the joint effect of atmosphere moisture and aerosol optical depth, a variation of aerosol direct radiative forcing is weakened, and the overall trend shows that aerosol direct radiative forcing variation trend to moderation (0.22 W·m-2 in the country and 0.29 W·m-2 in the city).Entering the 21st Century, solar radiation tends to moderation. This tendency indicates the cause for solar radiation change of China in the 1990s is different from Europe and America, and aerosol decline is not the major contributor. On the other hand, it also demonstrates if the air quality improves in the future, the solar radiation over the central and east of southern China may rise again.

     

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