Studies on the impact of solar activity on climate system are very important in understanding global climate change. Previous studies in this field were mostly focus on temperature, wind and geopotential height. In th...Studies on the impact of solar activity on climate system are very important in understanding global climate change. Previous studies in this field were mostly focus on temperature, wind and geopotential height. In this paper, interdecadal correlations of solar activity with Winter Snow Depth Index （WSDI） over the Tibetan Plateau, Arctic Oscillation Index （AOI） and the East Asian Winter Monsoon Index （EAWMI） are detected respectively by using Solar Radio Flux （SRF）, Total Solar Irradiance （TSI） and Solar Sunspot Number （SSN） data and statistical methods. Arctic Oscillation and East Asian winter monsoon are typical modes of the East Asian atmospheric circulation. Research results show that on inter-decadal time scale over 11-year solar cycle, the sun modulated changes of winter snow depth over the Tibetan Plateau and East Asian atmospheric circulation. At the fourth lag year, the correlation coefficient of SRF and snow depth is 0.8013 at 0.05 significance level by Monte-Carlo test method. Our study also shows that winter snow depth over the Tibetan Plateau has significant lead and lag correlations with Arctic Oscillation and the East Asian winter monsoon on long time scale. With more snow in winter, the phase of Arctic Oscillation is positive, and East Asian winter monsoon is weak, while with less snow, the parameters are reversed. An example is the winter of 2012/2013, with decreased Tibetan Plateau snow, phase of Arctic Oscillation was negative, and East Asian winter monsoon was strong.展开更多
The distribution of winter-spring snow cover over the Tibetan Plateau （TP） and its relationship with summer precipitation in the middle and lower reaches of Yangtze River Valley （MLYRV） during 2003-2013 have been ...The distribution of winter-spring snow cover over the Tibetan Plateau （TP） and its relationship with summer precipitation in the middle and lower reaches of Yangtze River Valley （MLYRV） during 2003-2013 have been investigated with the moderate-resolution imaging spectrometer （MODIS） Terra data （MOD10A2） and precipitation observations. Results show that snow cover percentage （SCP） remains approximately 20% in winter and spring then tails off to below 5% with warmer temperature and snow melt in summer. The lower and highest percentages present a declining tendency while the middle SCP exhibits an opposite variation. The maximum value appears from the middle of October to March and the minimum emerges from July to August. The annual and winter-spring SCPs present a decreasing tendency. Snow cover is mainly situated in the periphery of the plateau and mountainous regions, and less snow in the interior of the plateau, basin and valley areas in view of snow cover frequency （SCF） over the TP. Whatever annual or winter-spring snow cover, they all have remarkable declining tendency during 2003-2013, and annual snow cover presents a decreasing trend in the interior of the TP and increasing trend in the periphery of the TP. Hie multi-year averaged eight-day SCP is negatively related to mean precipitation in the MLYRV. Spring SCP is negatively related to summer precipitation while winter SCP is positively related to summer precipitation in most parts of the MLYRV. Hence, the influence of winter snow cover on precipitation is much more significant than that in spring on the basis of correlation analysis. The oscillation of SCF from southeast to northwest over the TP corresponds well to the beginning,development and cessation of the rain belt in eastern China.展开更多
利用美国冰雪资料中心（National Snow and Ice Data Center）提供的前苏联1948~1994年逐日积雪深度资料,定义了冬季雪深增量的概念,探讨了欧亚大陆秋末雪深、冬季雪深、冬季雪深增量的时空演变规律,通过比较分析三者的异常变化特征,揭...利用美国冰雪资料中心（National Snow and Ice Data Center）提供的前苏联1948~1994年逐日积雪深度资料,定义了冬季雪深增量的概念,探讨了欧亚大陆秋末雪深、冬季雪深、冬季雪深增量的时空演变规律,通过比较分析三者的异常变化特征,揭示了三者之间可能存在的联系。经验正交函数分解（EOF）结果表明：欧亚大陆冬季雪深、冬季雪深增量的第一模态的空间分布特征均为大致以50°N为界的南北反相变化,欧亚大陆北部的积雪深度和冬季雪深增量都呈现出一致性的变化趋势;两者对应的时间序列均反映了显著的年代际变化特征,且年代际转变均发生在20世纪70年代中期前后。第二模态则呈现出欧亚大陆东、西部反相的偶极型空间分布特征。进一步分析表明,欧亚大陆秋末雪深无论从空间分布还是时间演变来看与冬季雪深几乎不存在相关性。欧亚大陆冬季雪深变化主要是冬季雪深增量影响所致,与秋末雪深无关。展开更多
基金funded by the National Science Foundation of China (No. 41575091)the National Basic Research and Development (973) Program of China (Grant No. 2012CB957803 and No. 2012CB957804)
文摘Studies on the impact of solar activity on climate system are very important in understanding global climate change. Previous studies in this field were mostly focus on temperature, wind and geopotential height. In this paper, interdecadal correlations of solar activity with Winter Snow Depth Index （WSDI） over the Tibetan Plateau, Arctic Oscillation Index （AOI） and the East Asian Winter Monsoon Index （EAWMI） are detected respectively by using Solar Radio Flux （SRF）, Total Solar Irradiance （TSI） and Solar Sunspot Number （SSN） data and statistical methods. Arctic Oscillation and East Asian winter monsoon are typical modes of the East Asian atmospheric circulation. Research results show that on inter-decadal time scale over 11-year solar cycle, the sun modulated changes of winter snow depth over the Tibetan Plateau and East Asian atmospheric circulation. At the fourth lag year, the correlation coefficient of SRF and snow depth is 0.8013 at 0.05 significance level by Monte-Carlo test method. Our study also shows that winter snow depth over the Tibetan Plateau has significant lead and lag correlations with Arctic Oscillation and the East Asian winter monsoon on long time scale. With more snow in winter, the phase of Arctic Oscillation is positive, and East Asian winter monsoon is weak, while with less snow, the parameters are reversed. An example is the winter of 2012/2013, with decreased Tibetan Plateau snow, phase of Arctic Oscillation was negative, and East Asian winter monsoon was strong.
基金supported by the National Natural Science Foundation of China(Grant No.41130960)the Project of the China Meteorological Administration(Grant Nos.CCSF201515 and CMAGJ2013M51)
文摘The distribution of winter-spring snow cover over the Tibetan Plateau （TP） and its relationship with summer precipitation in the middle and lower reaches of Yangtze River Valley （MLYRV） during 2003-2013 have been investigated with the moderate-resolution imaging spectrometer （MODIS） Terra data （MOD10A2） and precipitation observations. Results show that snow cover percentage （SCP） remains approximately 20% in winter and spring then tails off to below 5% with warmer temperature and snow melt in summer. The lower and highest percentages present a declining tendency while the middle SCP exhibits an opposite variation. The maximum value appears from the middle of October to March and the minimum emerges from July to August. The annual and winter-spring SCPs present a decreasing tendency. Snow cover is mainly situated in the periphery of the plateau and mountainous regions, and less snow in the interior of the plateau, basin and valley areas in view of snow cover frequency （SCF） over the TP. Whatever annual or winter-spring snow cover, they all have remarkable declining tendency during 2003-2013, and annual snow cover presents a decreasing trend in the interior of the TP and increasing trend in the periphery of the TP. Hie multi-year averaged eight-day SCP is negatively related to mean precipitation in the MLYRV. Spring SCP is negatively related to summer precipitation while winter SCP is positively related to summer precipitation in most parts of the MLYRV. Hence, the influence of winter snow cover on precipitation is much more significant than that in spring on the basis of correlation analysis. The oscillation of SCF from southeast to northwest over the TP corresponds well to the beginning,development and cessation of the rain belt in eastern China.
文摘利用美国冰雪资料中心（National Snow and Ice Data Center）提供的前苏联1948~1994年逐日积雪深度资料,定义了冬季雪深增量的概念,探讨了欧亚大陆秋末雪深、冬季雪深、冬季雪深增量的时空演变规律,通过比较分析三者的异常变化特征,揭示了三者之间可能存在的联系。经验正交函数分解（EOF）结果表明：欧亚大陆冬季雪深、冬季雪深增量的第一模态的空间分布特征均为大致以50°N为界的南北反相变化,欧亚大陆北部的积雪深度和冬季雪深增量都呈现出一致性的变化趋势;两者对应的时间序列均反映了显著的年代际变化特征,且年代际转变均发生在20世纪70年代中期前后。第二模态则呈现出欧亚大陆东、西部反相的偶极型空间分布特征。进一步分析表明,欧亚大陆秋末雪深无论从空间分布还是时间演变来看与冬季雪深几乎不存在相关性。欧亚大陆冬季雪深变化主要是冬季雪深增量影响所致,与秋末雪深无关。
