| 近50 a西安太阳辐射变化特征及相关影响因子分析 |
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| 引用本文： | 彭艳,王钊,李星敏,堇妍.近50 a西安太阳辐射变化特征及相关影响因子分析[J].干旱区地理,2012,35(5):738-745. |
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| 作者姓名： | 彭艳 王钊 李星敏 堇妍 |
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| 作者单位： | 1. 陕西省气象科学研究所,陕西西安,710015
2. 陕西省农业遥感信息中心,陕西西安,710015 |
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| 基金项目： | 陕西省气象局基金，陕西省气象局重点项目 |
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| 摘 要： | 根据常规气象观测资料以及MODIS卫星气溶胶产品，分析了西安近50 a总辐射变化特征及其相关影响因子。结果表明：西安地区1961-2005年总辐射变化经历了“持续”、“变暗”、“变亮”、“再变暗”4个阶段，西安总辐射的变化幅度较全国平均变化幅度大，其“变亮”过程开始于1985年，较全国平均时间略早；西安4个季节总辐射总体均呈现出下降趋势，其变化幅度存在一定差异。通过对云量、气溶胶、水汽压、相对湿度等影响因子的分析，水汽压和相对湿度对总辐射变化影响不明显，总云量和气溶胶的变化对西安总辐射的变化存在较显著的影响，春、夏季总辐射的变化主要受云量和气溶胶直接辐射强迫的共同影响，其中总云量的变化在一定程度上决定了总辐射变化的振幅，城市发展所导致的气溶胶增加所产生的直接辐射强迫作用可能决定了总辐射的总体下降趋势；秋、冬季节的总辐射下降趋势主要与气溶胶的直接辐射强迫有关。
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| 关 键 词： | 总辐射 气溶胶 云量 直接辐射强迫 |
| 收稿时间： | 2011-11-21; |
Variation of surface solar radiation and its impact factors of Xi 'an in recent 50 years |
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| PENG Yan
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WANG Zhao
,
LI Xing-min
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DONG Yan.Variation of surface solar radiation and its impact factors of Xi 'an in recent 50 years[J].Arid Land Geography,2012,35(5):738-745. |
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| Authors: | PENG Yan WANG Zhao LI Xing-min DONG Yan |
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| Institution: | 1 Meteorological Institute of Shaanxi Province, Xi’an 710015,Shaanxi,China； 2 Shaanxi Remote Sensing Information Center for Agriculture, Xi’an 710015,Shaanxi,China |
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| Abstract: | In this study, nearly 50 years of diurnal surface solar radiation data and nearly 60 years of diurnal meteorological data, including total cloud amount, visibility, water vapor pressure and humidity, and 10 years of MODIS aerosol products, have been analyzed to examine the regional surface solar radiation change and its impact factors over Xi’an City,Shaanxi Province,China. We find that there is a significant decreasing of surface solar radiation from 1970s to 1980s. From 1974 to 1984, surface solar radiation over Xi’an decreased by approximately 18.2 %·(10 a)-1, and increased by 14.9 %·(10 a)-1 from 1985 to 1995, form 1996 to 2005 there also a decrease by 15.2 %·(10 a)-1. The average decreasing trend of surface solar radiation over XiJP8]’aJP]n was larger than that over the mainland in China and the time of “brightening” period was a little earlier over Xi’an. The seasonal variation of surface solar radiation shows that although there was some difference in variation scope of total solar radiation, there was a basically downtrend in four seasons. The variation in summer and autumn was most similar with annual change. While in spring there was an obviously decreasing from 1963 to the end of 1980s, then it began to increase slowly. In winter there was a steady decline of surface solar radiation since 1963. In order to find out the main course of decrease in surface solar radiation, we analyzed the principal meteorological factors contributed to surface solar radiation. First we studied the variation of total cloud amount, which may be one of the dominant affecting factors. Generally the increasing of total cloud amount can reduce the amount of solar radiation reaching the surface of the earth. The average decreasing trend of annual total cloud amount suggested that there may be another important factor for the decrease of annual solar radiation. Further more, after analyzed water vapor pressure, relative humidity, visibility and aerosol optical depth. We concluded that there also a decrease of water vapor pressure and relative humidity, so these two factors have little effect on decrease of total solar radiation over Xi’an. While there were an obviously decrease of visibility and an increase of AOD over Xi’an. This means that from 1980s there was an increase of anthropogenic aerosol due to the development of cities. Moreover with the effect of special terrain and prevailing winds, anthropogenic aerosols accumulated at east part of Guanzhong in Shaanxi province, thus there is a high aerosol concentration above the surface layer at Xi’an and its east region. It implies that AOD plays a major role in reducing the solar radiation reaching the surface. In generally, we notice that impact factors of solar radiation were various in different seasons. In spring and summer, the total cloud amount and direct radiation force of aerosol play the same role for the variation of solar radiation, total cloud amount limited the variation range while the direct radioactive stress resulting from the increase of anthropogenic aerosols determined the downward trend. And in autumn and winter the direct radioactive stress of anthropogenic aerosols may be more important. |
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| Keywords: | surface solar radiation aerosols total cloud amount direct radiative stress |
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