Using the total ozone mapping spectrometer (TOMS) aerosol optical depth (AOD) data and the sunshine duration, fog days, low cloud cover (LCC), etc. meteorological data in 1979-2000 in North China, as well as empirical...Using the total ozone mapping spectrometer (TOMS) aerosol optical depth (AOD) data and the sunshine duration, fog days, low cloud cover (LCC), etc. meteorological data in 1979-2000 in North China, as well as empirical orthogonal function (EOF) mode statistical analyses method, the winter aerosol distributive character of Beijing and peripheral city agglomeration and its influence effect on regional climate are investigated in this paper, especially the relation between aerosol influence effect and distinct change regions of eigenvectors of EOF mode. It is found from analyzing the regional distribution of the long-term averaged winter TOMS AOD that there is a large-scale relatively stable high value zone of aerosol concentration in the valley of the Beijing and peripheral U-shape megarelief. A high correlation area of AOD between Beijing and its southern peripheral exists in winter, and in this significant region of aerosol interaction, there is 'in-phase' character of the interannual variations of winter AOD, fog days, and LCCs. It indicates that the variations of aerosol in Beijing and its peripheral areas have impacts on interannual changes of fog days and LCCs in this area. The EOF analyses of the meteorological data further reveal the climate change regions and long-term trends of winter sunshine duration-reducing, and LCC- and fog days-increasing in North China. The areas of significant changes of the first EOF eigenvectors (FEE) of sunshine duration, fog days, LCCs almost superpose on corresponding marked regions of interdecadal differences between the 1990s and 1980s, and all accord with the S-N zonal high value pattern and high correlation region of winter AOD in Beijing and its peripheral areas. Interannual variations of their associated time coefficients (ATC) are in phase with that of regional mean AOD, and both of them have a secular rising trend. Results by EOF mode analyses depict the regional climatic change principal character of winter sunshine duration-reducing, and LCC- and fog days-increasing in peripheral areas to the south of Beijing, and reveal the regional influence effect of aerosol, i.e. the high value zone of long-term averaged winter AOD, significant change regions of FEE of sunshine duration, fog days, and LCC all lie in peripheral city agglomeration to the south of Beijing. These distributive features above suggest that there exists a regional strengthening trend of aerosol climatic effect within influence domain in peripheral city agglomeration to the south of Beijing.展开更多
在全球气候变化背景下,极端高温事件频发,且自21世纪以来其发生频率明显增加,对农业生产及人体健康造成深远影响。为探究地形复杂的伊犁河流域极端高温时空演变规律,本文利用1991—2020年该流域11个气象站逐日气温数据,计算夏季日数(SU...在全球气候变化背景下,极端高温事件频发,且自21世纪以来其发生频率明显增加,对农业生产及人体健康造成深远影响。为探究地形复杂的伊犁河流域极端高温时空演变规律,本文利用1991—2020年该流域11个气象站逐日气温数据,计算夏季日数(SU25)、热夜日数(TR20)、暖昼日数(TX90p)、暖夜日数(TN90p)、日最高气温极高值(TXx)和日最低气温极高值(TNx)6个极端高温指数,并通过线性趋势分析、Mann-Kendall突变检验、经验正交函数分解(Empirical Orthogonal Function decomposition,EOF)以及克里金插值法(Kriging),系统分析伊犁河流域6个极端高温指数的时空变化特征。结果表明:伊犁河流域大部分极端高温指数整体呈快速增长趋势,且在20世纪90年代至21世纪初发生显著突变。其中SU25、TX90p、TXx和TNx的增长速率突出,2015年后各指数处于加速增长阶段。空间分布上,流域大部分极端高温指数呈现明显的“西北高、东南低”格局:西北部为高温指数高值区,昭苏东北部、特克斯、巩留及尼勒克西南部形成稳定低值中心。由EOF分解得到TXx与TNx的空间分布存在两种典型模态,其演变特征与流域极端高温整体变化趋势具有高度一致性。展开更多
文摘Using the total ozone mapping spectrometer (TOMS) aerosol optical depth (AOD) data and the sunshine duration, fog days, low cloud cover (LCC), etc. meteorological data in 1979-2000 in North China, as well as empirical orthogonal function (EOF) mode statistical analyses method, the winter aerosol distributive character of Beijing and peripheral city agglomeration and its influence effect on regional climate are investigated in this paper, especially the relation between aerosol influence effect and distinct change regions of eigenvectors of EOF mode. It is found from analyzing the regional distribution of the long-term averaged winter TOMS AOD that there is a large-scale relatively stable high value zone of aerosol concentration in the valley of the Beijing and peripheral U-shape megarelief. A high correlation area of AOD between Beijing and its southern peripheral exists in winter, and in this significant region of aerosol interaction, there is 'in-phase' character of the interannual variations of winter AOD, fog days, and LCCs. It indicates that the variations of aerosol in Beijing and its peripheral areas have impacts on interannual changes of fog days and LCCs in this area. The EOF analyses of the meteorological data further reveal the climate change regions and long-term trends of winter sunshine duration-reducing, and LCC- and fog days-increasing in North China. The areas of significant changes of the first EOF eigenvectors (FEE) of sunshine duration, fog days, LCCs almost superpose on corresponding marked regions of interdecadal differences between the 1990s and 1980s, and all accord with the S-N zonal high value pattern and high correlation region of winter AOD in Beijing and its peripheral areas. Interannual variations of their associated time coefficients (ATC) are in phase with that of regional mean AOD, and both of them have a secular rising trend. Results by EOF mode analyses depict the regional climatic change principal character of winter sunshine duration-reducing, and LCC- and fog days-increasing in peripheral areas to the south of Beijing, and reveal the regional influence effect of aerosol, i.e. the high value zone of long-term averaged winter AOD, significant change regions of FEE of sunshine duration, fog days, and LCC all lie in peripheral city agglomeration to the south of Beijing. These distributive features above suggest that there exists a regional strengthening trend of aerosol climatic effect within influence domain in peripheral city agglomeration to the south of Beijing.
文摘在全球气候变化背景下,极端高温事件频发,且自21世纪以来其发生频率明显增加,对农业生产及人体健康造成深远影响。为探究地形复杂的伊犁河流域极端高温时空演变规律,本文利用1991—2020年该流域11个气象站逐日气温数据,计算夏季日数(SU25)、热夜日数(TR20)、暖昼日数(TX90p)、暖夜日数(TN90p)、日最高气温极高值(TXx)和日最低气温极高值(TNx)6个极端高温指数,并通过线性趋势分析、Mann-Kendall突变检验、经验正交函数分解(Empirical Orthogonal Function decomposition,EOF)以及克里金插值法(Kriging),系统分析伊犁河流域6个极端高温指数的时空变化特征。结果表明:伊犁河流域大部分极端高温指数整体呈快速增长趋势,且在20世纪90年代至21世纪初发生显著突变。其中SU25、TX90p、TXx和TNx的增长速率突出,2015年后各指数处于加速增长阶段。空间分布上,流域大部分极端高温指数呈现明显的“西北高、东南低”格局:西北部为高温指数高值区,昭苏东北部、特克斯、巩留及尼勒克西南部形成稳定低值中心。由EOF分解得到TXx与TNx的空间分布存在两种典型模态,其演变特征与流域极端高温整体变化趋势具有高度一致性。
