The impact of E1 Nino on the precipitation in China for different seasons are investigateddiagnostically. It is found that E1 Nino can influence the precipitation in China significantly duringits mature phase. In the ...The impact of E1 Nino on the precipitation in China for different seasons are investigateddiagnostically. It is found that E1 Nino can influence the precipitation in China significantly duringits mature phase. In the Northern winter, spring and autumn, the positive precipitation anomaliesare found in the southern part of China during the E1 Nino mature phase. In the Northernsummer, the patterns of the precipitation anomalies in the E1 Nifio mature phase are different fromthose in the other seasons. The negative precipitation anomalies appear in both southern andnorthern parts of China, while in between around the lower reaches of the Yangtze River and theHuaihe River valleys the precipitation anomalies tend to be positive.In the Northern winter, spring and autumn, the physical process by which E1 Nino affects theprecipitation in the southern part of China can be explained by the features of the circulationanomalies over East Asia during the E1 Nino mature phase (Zhang et al. 1996). The appearance ofan anticyclonic anomaly to the north of the maritime continent in the lower troposphere during theE1 Nino mature phase intensifies the subtropical high in the western Pacific and makes it shiftwestward. The associated southwesterly flow is responsible for the positive precipitation anomaliesin the southern part of China. In the Northern summer, the intensified western Pacific subtropicalhigh covers the southeastern periphery of China so that the precipitation there becomes less. In addition, the weakening of the indian monsoon provides less moisture inflow to the northern part ofChina.展开更多
Using the automatic weather station data obtained from the Tibetan Plateau (TP), the normalized dif- ference vegetation index and the monthly precipitation data of China and by the methods of correlation and composite...Using the automatic weather station data obtained from the Tibetan Plateau (TP), the normalized dif- ference vegetation index and the monthly precipitation data of China and by the methods of correlation and composite analysis, preliminary analytical results are achieved concerning the relationships be- tween TP NDVI change and its surface heat source and precipitation of China. The results of our re- search may lead to the following conclusions: (1) A positive correlation relationship exists between TP NDVI change and its surface heat source, including the sensible heat and the latent heat. As to the correlation of the former, it is more remarkable in western TP than in eastern TP, and as to the correla- tion of the latter, however it turns out contrary. (2) With the improvement of TP vegetation, its surface heat source of every season is also mainly reinforced, especially in summer. As to the contribution of the sensible heat and the latent heat to the increment of the TP surface heat source intensity, the for- mer is comparatively more significant than the latter in winter and spring, while in summer and autumn, the two have almost the same importance. (3) The correlation coefficient between summer NDVI over TP and the corresponding period precipitation of China displays a belt distribution of "+?+" from south to north China. (4) Anomalous surface heating field over TP derived from vegetation change is probably an important factor to affect summer precipitation of China.展开更多
By using the NCAR CCM1 model, we have designed six sensitive experiments, which are increased and decreased SST (sea surface temperature) by 1℃ each in the SCS (South China Sea) and in the West Pacific warm pool, inc...By using the NCAR CCM1 model, we have designed six sensitive experiments, which are increased and decreased SST (sea surface temperature) by 1℃ each in the SCS (South China Sea) and in the West Pacific warm pool, increased and decreased SST by 1℃ in the warm pool with increased SST by 1℃ in the SCS. All experiments are integrated from April to July. Comparing with the control experiment, we have analyzed the anomalies of the wind field at the upper and lower layers, the anomalies of the seasonal variability of the monsoon and precipitation for each experiment. In the result, we have found that the SST anomaly (SSTA) in the SCS greatly affects the seasonal variability of the SCS monsoon and precipitation in China, especially during the cold period of SST in the SCS. The impact of SSTA in the warm pool on SCS monsoon is also found. but is weak as compared to the effect of SST anomaly in the SCS. Besides, its impact on rainfall in China is uncertain.展开更多
利用1979—2014年ERA-Interim逐月的风场、海平面气压场和位势高度场等再分析资料以及中国160站降水观测资料,采用回归分析等方法分析了盛夏(7、8月)南海(South China Sea,SCS)低空越赤道气流(Cross-Equatorial Flow,CEF)的变化及其与...利用1979—2014年ERA-Interim逐月的风场、海平面气压场和位势高度场等再分析资料以及中国160站降水观测资料,采用回归分析等方法分析了盛夏(7、8月)南海(South China Sea,SCS)低空越赤道气流(Cross-Equatorial Flow,CEF)的变化及其与东亚夏季风的联系,结果表明:盛夏南海低空越赤道气流(SCEF)强度指数与南海夏季风强度指数呈显著的正相关关系,与东亚副热带夏季风强度指数呈显著的负相关关系。当盛夏SCEF偏强(弱)时,亚洲热带低压及西太平洋赤道辐合带增强(减弱),西太平洋副热带高压强度减弱(增强)、东撤(西伸),南海北部和西北太平洋地区为明显的气旋式(反气旋式)环流异常,使得南海夏季风增强(减弱)和东亚副热带夏季风减弱(增强)。此外,当盛夏SCEF偏强时,由于东亚副热带夏季风减弱,我国华南地区为东北风异常,华北地区为偏南风异常,受其影响,我国华南地区为显著的水汽辐合区,华中地区为显著的水汽辐散区,使得盛夏华南地区降水增多,华中地区降水减少;反之亦然。展开更多
The relationship of Kuroshio sea surface temperature anomaly (SSTA) in theprevious winter and summer rainfall in China was analyzed based on observational studies andnumerical simulations. Observational results indica...The relationship of Kuroshio sea surface temperature anomaly (SSTA) in theprevious winter and summer rainfall in China was analyzed based on observational studies andnumerical simulations. Observational results indicate that there is a close relation betweenKuroshio SSTA and precipitation in China. When Kuroshio SSTA is positive, the western Pacificsubtropical high will be stronger and extend farther westward in, the following summer, with Asiansummer monsoon weaker and the frontal precipitation further southward. As a result, summerprecipitation increases (decreases) in the mid-lower reaches of the Yangtze River (in North andNortheast China), and vice versa. Conclusions drawn by NCAR-CCM3 testify the observational results.展开更多
In this study, seasonal predictions were applied to precipitation in China on a monthly basis based on a multivariate linear regression with an adaptive choice of predictors drawn from regularly updated climate indice...In this study, seasonal predictions were applied to precipitation in China on a monthly basis based on a multivariate linear regression with an adaptive choice of predictors drawn from regularly updated climate indices with a two to twelve month lead time. A leave-one-out cross validation was applied to obtain hindcast skill at a 1% significance level. The skill of forecast models at a monthly scale and their significance levels were evaluated using Anomaly Correlation Coefficients （ACC） and Coefficients Of Determination （COD）. The monthly ACC skill ranged between 0.43 and 0.50 in Central China, 0.41-0.57 in East China, and 0.41 0.60 in South China. The dynamic link between large-scale climate indices with lead time and the precipitation in China is also discussed based on Singular Value Decomposition Analysis （SVDA） and Correlation Analysis （CA）.展开更多
文摘The impact of E1 Nino on the precipitation in China for different seasons are investigateddiagnostically. It is found that E1 Nino can influence the precipitation in China significantly duringits mature phase. In the Northern winter, spring and autumn, the positive precipitation anomaliesare found in the southern part of China during the E1 Nino mature phase. In the Northernsummer, the patterns of the precipitation anomalies in the E1 Nifio mature phase are different fromthose in the other seasons. The negative precipitation anomalies appear in both southern andnorthern parts of China, while in between around the lower reaches of the Yangtze River and theHuaihe River valleys the precipitation anomalies tend to be positive.In the Northern winter, spring and autumn, the physical process by which E1 Nino affects theprecipitation in the southern part of China can be explained by the features of the circulationanomalies over East Asia during the E1 Nino mature phase (Zhang et al. 1996). The appearance ofan anticyclonic anomaly to the north of the maritime continent in the lower troposphere during theE1 Nino mature phase intensifies the subtropical high in the western Pacific and makes it shiftwestward. The associated southwesterly flow is responsible for the positive precipitation anomaliesin the southern part of China. In the Northern summer, the intensified western Pacific subtropicalhigh covers the southeastern periphery of China so that the precipitation there becomes less. In addition, the weakening of the indian monsoon provides less moisture inflow to the northern part ofChina.
基金the National Natural Science Foundation of China (Grant No. 40675037)the Key Program of the Sichuan Province Youth Science and Tech-nology Foundation (Grant No. 05ZQ026-023)
文摘Using the automatic weather station data obtained from the Tibetan Plateau (TP), the normalized dif- ference vegetation index and the monthly precipitation data of China and by the methods of correlation and composite analysis, preliminary analytical results are achieved concerning the relationships be- tween TP NDVI change and its surface heat source and precipitation of China. The results of our re- search may lead to the following conclusions: (1) A positive correlation relationship exists between TP NDVI change and its surface heat source, including the sensible heat and the latent heat. As to the correlation of the former, it is more remarkable in western TP than in eastern TP, and as to the correla- tion of the latter, however it turns out contrary. (2) With the improvement of TP vegetation, its surface heat source of every season is also mainly reinforced, especially in summer. As to the contribution of the sensible heat and the latent heat to the increment of the TP surface heat source intensity, the for- mer is comparatively more significant than the latter in winter and spring, while in summer and autumn, the two have almost the same importance. (3) The correlation coefficient between summer NDVI over TP and the corresponding period precipitation of China displays a belt distribution of "+?+" from south to north China. (4) Anomalous surface heating field over TP derived from vegetation change is probably an important factor to affect summer precipitation of China.
基金The paper is jointly supported by the National Natural Science Foundation of China under the Program of 49375245by the Monsoon Fund of China Meteorological Administration
文摘By using the NCAR CCM1 model, we have designed six sensitive experiments, which are increased and decreased SST (sea surface temperature) by 1℃ each in the SCS (South China Sea) and in the West Pacific warm pool, increased and decreased SST by 1℃ in the warm pool with increased SST by 1℃ in the SCS. All experiments are integrated from April to July. Comparing with the control experiment, we have analyzed the anomalies of the wind field at the upper and lower layers, the anomalies of the seasonal variability of the monsoon and precipitation for each experiment. In the result, we have found that the SST anomaly (SSTA) in the SCS greatly affects the seasonal variability of the SCS monsoon and precipitation in China, especially during the cold period of SST in the SCS. The impact of SSTA in the warm pool on SCS monsoon is also found. but is weak as compared to the effect of SST anomaly in the SCS. Besides, its impact on rainfall in China is uncertain.
文摘利用1979—2014年ERA-Interim逐月的风场、海平面气压场和位势高度场等再分析资料以及中国160站降水观测资料,采用回归分析等方法分析了盛夏(7、8月)南海(South China Sea,SCS)低空越赤道气流(Cross-Equatorial Flow,CEF)的变化及其与东亚夏季风的联系,结果表明:盛夏南海低空越赤道气流(SCEF)强度指数与南海夏季风强度指数呈显著的正相关关系,与东亚副热带夏季风强度指数呈显著的负相关关系。当盛夏SCEF偏强(弱)时,亚洲热带低压及西太平洋赤道辐合带增强(减弱),西太平洋副热带高压强度减弱(增强)、东撤(西伸),南海北部和西北太平洋地区为明显的气旋式(反气旋式)环流异常,使得南海夏季风增强(减弱)和东亚副热带夏季风减弱(增强)。此外,当盛夏SCEF偏强时,由于东亚副热带夏季风减弱,我国华南地区为东北风异常,华北地区为偏南风异常,受其影响,我国华南地区为显著的水汽辐合区,华中地区为显著的水汽辐散区,使得盛夏华南地区降水增多,华中地区降水减少;反之亦然。
基金This study is supported by the National Natural Science Foundation of China under No. Grant 40175023 and by the GradateEducation and Innovation Project of Jiangsu Province: No. E30000008098-2.
文摘The relationship of Kuroshio sea surface temperature anomaly (SSTA) in theprevious winter and summer rainfall in China was analyzed based on observational studies andnumerical simulations. Observational results indicate that there is a close relation betweenKuroshio SSTA and precipitation in China. When Kuroshio SSTA is positive, the western Pacificsubtropical high will be stronger and extend farther westward in, the following summer, with Asiansummer monsoon weaker and the frontal precipitation further southward. As a result, summerprecipitation increases (decreases) in the mid-lower reaches of the Yangtze River (in North andNortheast China), and vice versa. Conclusions drawn by NCAR-CCM3 testify the observational results.
基金funded by agrant (CATER 2009-1147) from the Korea Meteorological Administration ResearchDevelopment Program of the Republic of Korea
文摘In this study, seasonal predictions were applied to precipitation in China on a monthly basis based on a multivariate linear regression with an adaptive choice of predictors drawn from regularly updated climate indices with a two to twelve month lead time. A leave-one-out cross validation was applied to obtain hindcast skill at a 1% significance level. The skill of forecast models at a monthly scale and their significance levels were evaluated using Anomaly Correlation Coefficients （ACC） and Coefficients Of Determination （COD）. The monthly ACC skill ranged between 0.43 and 0.50 in Central China, 0.41-0.57 in East China, and 0.41 0.60 in South China. The dynamic link between large-scale climate indices with lead time and the precipitation in China is also discussed based on Singular Value Decomposition Analysis （SVDA） and Correlation Analysis （CA）.
