Relationship between summer rainfall over the east part of China and East-Asian Summer Monsoon (EASM) was studied based on the summer rainfall grade data set from 1470 to 1999 and the rain gauge data set from 1951 to ...Relationship between summer rainfall over the east part of China and East-Asian Summer Monsoon (EASM) was studied based on the summer rainfall grade data set from 1470 to 1999 and the rain gauge data set from 1951 to 1999 over the east part of China, and sea level pressure (SLP) data for the period of 1871-2000. A distinct 80a-oscillation of summer rainfall was found over North China (NC), southern part of Northeast China, over the middle and lower reaches of the Yangtze River (YR) and South China (SC). The 80a oscillation of summer rainfall over NC was varied in phase with that over SC, and was out of phase to that along the middle and lower reaches of the Yangtze River. Summer rainfall over NC correlated negatively with the SLP averaged for the area from 105 degreesE to 120 degreesE, and from 30 degreesN to 35 degreesN, but positively to that for the area from 120 degreesE to 130 degreesE, and from 20 degreesN to 25 degreesN. Therefore, an index of EASM was defined by the difference of averaged SLP over the two regions. The summer rainfall over NC was greater than normal when the EASM was strong, and while drought occurred along the middle and lower reaches of the Yangtze River. The drought was found over NC, and flood along the middle and lower reaches of the Yangtze River when the EASM was close to normal. Finally, the interdecadal variability of EASM was studied by using of long term summer rainfall grade data set over NC for the past 530 years.展开更多
A regional climate model coupled with an aerosol model is employed to numerically simulate the direct climate effects of the anthropogenic aerosol emitted in South Asia and China in the East Asian summer monsoon durin...A regional climate model coupled with an aerosol model is employed to numerically simulate the direct climate effects of the anthropogenic aerosol emitted in South Asia and China in the East Asian summer monsoon during1988 to 2009.Based on the data of the numerical simulation,composite analysis and correlation analysis are used to make diagnostic study of climate dynamics.Results show that the month of maximum emission of the mean column burden of the anthropogenic aerosol in the main emission areas of South Asia is opposite in phase to that in China.Summer is the season of maximum emission amount in China,but the emission amounts are more in South Asia in spring and winter.On the whole,the mean column burden of the anthropogenic aerosol in China is relatively high compared with that in South Asia.The trend of distribution of aerosol is SW-NE in China,and Sichuan Basin is the emission center of aerosol.The effect of negative short wave radiative forcing alters the gradient of pressure between land and sea,weakening the development of East Asian summer monsoon over the northern part of Yangtze-Huaihe River Basin.We also discuss the feedback effect of East-Asian summer monsoon which is changed by the anthropogenic aerosol on the concentration and distribution of aerosol in China.展开更多
Based on the data analyses by using NCEP/ NCAR reanalysis data and other data (OLR, precipitation and temperature), it is shown that the tropospheric circulation and climate in East Asia and the northwestern Pacific ...Based on the data analyses by using NCEP/ NCAR reanalysis data and other data (OLR, precipitation and temperature), it is shown that the tropospheric circulation and climate in East Asia and the northwestern Pacific region have the evident quasi-biennial oscillation (TBO) feature. It is also shown that anomalous East Asian winter monsoon can impact the atmospheric circulation and climate variations in the following summer, particularly in East Asian region; there is clear interaction between anomalous East Asian winter monsoon and ENSO cycle. The continuous strong (weak) East Asian winter monsoon can excite El Ni o (La Ni a) through the air-sea interaction, the El Ni o (La Ni a) event can lead the East Asian winter monsoon to be weak (strong) through the teleconnections or remote responses. The strong or weak winter monsoon and ENSO cycle are linked each other. It can be suggested that interaction between anomalous East Asian winter monsoon and ENSO cycle is a fundamental origin of the TBO.展开更多
The impact of intraseasonal oscillation on the onset of summer monsoon in the South China Sea (SCS) region is studied by using NCEP reanalysis data,the SCSMEX data and precipitation data in China.It is shown that the ...The impact of intraseasonal oscillation on the onset of summer monsoon in the South China Sea (SCS) region is studied by using NCEP reanalysis data,the SCSMEX data and precipitation data in China.It is shown that the onset of summer monsoon in the South China Sea region is closely related to the activity of intraseasonal oscillation.Particularly,the existence of low frequency cyclone over the east of Philippines and its expanding into the South China Sea play an important role in the onset of the SCS summer monsoon.The analyses of the circulation pattern and summer rainfall showed that the climate variations in China caused by the strong and weak summer monsoons are completely different,even are out of the phase.Analyzing the activity of atmospheric intraseasonal oscillation (ISO),we found that the atmospheric ISO at 850 hPa over the SCS and neighboring regions is strong (weak) corresponding to strong (weak) SCS summer monsoon.The comparison of the atmospheric circulation pattern with the circulation pattern of atmospheric ISO showed that strong and weak East-Asian summer monsoon circulations (200 hPa and 850 hPa) should mainly result from the abnormal activity of atmospheric ISO.展开更多
Based on diagnostic results,a numerical study is made of the processes of Australian cold air activity affecting East Asian summer monsoon by using Kuo-Qian P-σ incorporated coordinate five-layer primitive equation s...Based on diagnostic results,a numerical study is made of the processes of Australian cold air activity affecting East Asian summer monsoon by using Kuo-Qian P-σ incorporated coordinate five-layer primitive equation spherical band model.Analysis is done of the response to the Southern Hemisphere circulation with and without cold air activity in Australia of the flow,rainfall and diabatic heating fields in the monsoon area of Asia,especially,East Asia,with special attention to the intensification and northward march of the monsoon due to the activity.It is found that the processes for the effect transmission are very analogous to the meridional propagation of quasi-40-day oscillation,together with the meridional wind disturbance showing south-north travel and the flow/rainfall fields exhibitirg corresponding movement in this direction,only with a 12-day lag.展开更多
Investigated statistically is the interrelation between East Asian winter monsoon(EAWM) and SST over sensitive areas of the Indian and Pacific Oceans.with focus on the relation of EAWM to strong ENSO signal area.i.e.,...Investigated statistically is the interrelation between East Asian winter monsoon(EAWM) and SST over sensitive areas of the Indian and Pacific Oceans.with focus on the relation of EAWM to strong ENSO signal area.i.e.,the equatorial eastern Pacific(EEP)SST.Evidence suggests that the EAWM variation is intimately associated not only with the EEP SST but with the equatorial western Pacific“warm pool”and equatorial Indian/northwestern Pacific Kuroshio SST as well:the EAWM and ENSO interact strongly with each other on the interannual time scales, exhibiting pronounced interdecadal variation mainly under the joint effect of the monsoon QBO and the monsoon/SST background field features on an interdecadal basis—when both fields are in the same phase(anti-phase).strong EAWM contributes to EEP SST rise(drop)in the following winter,corresponding to a warm(cold)ENSO cycle;the EAWM QBO causes ENSO cycle to be strong phase-locked with seasonal variation,making the EEP SST rise lasting from April—May to May—June of the next year,which plays an important role in maintaining a warm ENSO phase.展开更多
Zonal wind anomaly over the equatorial west- ern Pacific plays an important role in the occurrence of ENSO. The mechanism to produce zonal wind anomaly over the equatorial western Pacific is studied in this paper. It ...Zonal wind anomaly over the equatorial west- ern Pacific plays an important role in the occurrence of ENSO. The mechanism to produce zonal wind anomaly over the equatorial western Pacific is studied in this paper. It is shown clearly that zonal wind anomaly over the equatorial western Pacific is closely related to the anomaly of East- Asian winter monsoon. Anomalous strong (weak) East-Asian winter monsoon can excite not only the westerly (easterly) anomaly over the equatorial western Pacific but also a cyc- lonic (an anticyclonic) circulation over the east of the Philip- pines. The above anomalous circulation results from dy- namical impacts of anomalous pressure pattern due to the East-Asian winter monsoon. Because there is westward (eastward) pressure gradient over the equatorial western Pacific, i.e. there is ?? xp <0(> 0), during strong (weak) East-Asian winter monsoon.展开更多
By prescribing sea surface temperature anomalies(SSTAs)over eastern equatorial Pacific in January—March,the lag influence of ENSO(El Nino and La Nina)on monsoon over East Asia has been studied.The results suggest tha...By prescribing sea surface temperature anomalies(SSTAs)over eastern equatorial Pacific in January—March,the lag influence of ENSO(El Nino and La Nina)on monsoon over East Asia has been studied.The results suggest that,due to the excitation of atmospheric low-frequency oscillation by the SSTA,ENSO has significant lag influence on the monsoon over East Asia. During the summer after E1 Nino,the subtropical high over western Pacific is intensified and shows the northward and westward displacement,meanwhile,the rainfall over East China is below normal,especially in North China:during the winter after E1 Nino,both the Asian trough and the winter monsoon over East Asia are strengthened.During the summer after La Nina,the anomalous subtropical high prevails over the lower reaches of Yangtze(Changjiang)River,the rainfall between Yangtze and Huaihe Rivers is below normal:during the winter after La Nina, both the Asian trough and the winter monsoon over East Asia are weaker.Compared with La Nina,the effect of El Nino is stronger,but it is not always opposite to the one of La Nina.展开更多
基金This research was supported by National Key Program for Developing Basic Sciences(G 199804900-Part 1 ).
文摘Relationship between summer rainfall over the east part of China and East-Asian Summer Monsoon (EASM) was studied based on the summer rainfall grade data set from 1470 to 1999 and the rain gauge data set from 1951 to 1999 over the east part of China, and sea level pressure (SLP) data for the period of 1871-2000. A distinct 80a-oscillation of summer rainfall was found over North China (NC), southern part of Northeast China, over the middle and lower reaches of the Yangtze River (YR) and South China (SC). The 80a oscillation of summer rainfall over NC was varied in phase with that over SC, and was out of phase to that along the middle and lower reaches of the Yangtze River. Summer rainfall over NC correlated negatively with the SLP averaged for the area from 105 degreesE to 120 degreesE, and from 30 degreesN to 35 degreesN, but positively to that for the area from 120 degreesE to 130 degreesE, and from 20 degreesN to 25 degreesN. Therefore, an index of EASM was defined by the difference of averaged SLP over the two regions. The summer rainfall over NC was greater than normal when the EASM was strong, and while drought occurred along the middle and lower reaches of the Yangtze River. The drought was found over NC, and flood along the middle and lower reaches of the Yangtze River when the EASM was close to normal. Finally, the interdecadal variability of EASM was studied by using of long term summer rainfall grade data set over NC for the past 530 years.
基金National Key Fundamental Research Development and Planning 973 Project(2011CB403405)Natural Science Foundation of China(41075039+2 种基金41175065)Specialized Project of Public Welfare Industries(GYHY200806009)"Qing-lan"Project of Jiangsu Province(2009)
文摘A regional climate model coupled with an aerosol model is employed to numerically simulate the direct climate effects of the anthropogenic aerosol emitted in South Asia and China in the East Asian summer monsoon during1988 to 2009.Based on the data of the numerical simulation,composite analysis and correlation analysis are used to make diagnostic study of climate dynamics.Results show that the month of maximum emission of the mean column burden of the anthropogenic aerosol in the main emission areas of South Asia is opposite in phase to that in China.Summer is the season of maximum emission amount in China,but the emission amounts are more in South Asia in spring and winter.On the whole,the mean column burden of the anthropogenic aerosol in China is relatively high compared with that in South Asia.The trend of distribution of aerosol is SW-NE in China,and Sichuan Basin is the emission center of aerosol.The effect of negative short wave radiative forcing alters the gradient of pressure between land and sea,weakening the development of East Asian summer monsoon over the northern part of Yangtze-Huaihe River Basin.We also discuss the feedback effect of East-Asian summer monsoon which is changed by the anthropogenic aerosol on the concentration and distribution of aerosol in China.
基金National Key Basic Science Program in China (G1998040900)NSFC (49823002).
文摘Based on the data analyses by using NCEP/ NCAR reanalysis data and other data (OLR, precipitation and temperature), it is shown that the tropospheric circulation and climate in East Asia and the northwestern Pacific region have the evident quasi-biennial oscillation (TBO) feature. It is also shown that anomalous East Asian winter monsoon can impact the atmospheric circulation and climate variations in the following summer, particularly in East Asian region; there is clear interaction between anomalous East Asian winter monsoon and ENSO cycle. The continuous strong (weak) East Asian winter monsoon can excite El Ni o (La Ni a) through the air-sea interaction, the El Ni o (La Ni a) event can lead the East Asian winter monsoon to be weak (strong) through the teleconnections or remote responses. The strong or weak winter monsoon and ENSO cycle are linked each other. It can be suggested that interaction between anomalous East Asian winter monsoon and ENSO cycle is a fundamental origin of the TBO.
基金National Key Basic Science Program in China (G1998040903)State Key Project-SCSMEX
文摘The impact of intraseasonal oscillation on the onset of summer monsoon in the South China Sea (SCS) region is studied by using NCEP reanalysis data,the SCSMEX data and precipitation data in China.It is shown that the onset of summer monsoon in the South China Sea region is closely related to the activity of intraseasonal oscillation.Particularly,the existence of low frequency cyclone over the east of Philippines and its expanding into the South China Sea play an important role in the onset of the SCS summer monsoon.The analyses of the circulation pattern and summer rainfall showed that the climate variations in China caused by the strong and weak summer monsoons are completely different,even are out of the phase.Analyzing the activity of atmospheric intraseasonal oscillation (ISO),we found that the atmospheric ISO at 850 hPa over the SCS and neighboring regions is strong (weak) corresponding to strong (weak) SCS summer monsoon.The comparison of the atmospheric circulation pattern with the circulation pattern of atmospheric ISO showed that strong and weak East-Asian summer monsoon circulations (200 hPa and 850 hPa) should mainly result from the abnormal activity of atmospheric ISO.
基金National Natural Science Foundation of ChinaState Meteorological Administration Monsoon Research Funds
文摘Based on diagnostic results,a numerical study is made of the processes of Australian cold air activity affecting East Asian summer monsoon by using Kuo-Qian P-σ incorporated coordinate five-layer primitive equation spherical band model.Analysis is done of the response to the Southern Hemisphere circulation with and without cold air activity in Australia of the flow,rainfall and diabatic heating fields in the monsoon area of Asia,especially,East Asia,with special attention to the intensification and northward march of the monsoon due to the activity.It is found that the processes for the effect transmission are very analogous to the meridional propagation of quasi-40-day oscillation,together with the meridional wind disturbance showing south-north travel and the flow/rainfall fields exhibitirg corresponding movement in this direction,only with a 12-day lag.
基金Supported by the National Natural Science Foundation of China under Grant ATM-49705062.
文摘Investigated statistically is the interrelation between East Asian winter monsoon(EAWM) and SST over sensitive areas of the Indian and Pacific Oceans.with focus on the relation of EAWM to strong ENSO signal area.i.e.,the equatorial eastern Pacific(EEP)SST.Evidence suggests that the EAWM variation is intimately associated not only with the EEP SST but with the equatorial western Pacific“warm pool”and equatorial Indian/northwestern Pacific Kuroshio SST as well:the EAWM and ENSO interact strongly with each other on the interannual time scales, exhibiting pronounced interdecadal variation mainly under the joint effect of the monsoon QBO and the monsoon/SST background field features on an interdecadal basis—when both fields are in the same phase(anti-phase).strong EAWM contributes to EEP SST rise(drop)in the following winter,corresponding to a warm(cold)ENSO cycle;the EAWM QBO causes ENSO cycle to be strong phase-locked with seasonal variation,making the EEP SST rise lasting from April—May to May—June of the next year,which plays an important role in maintaining a warm ENSO phase.
基金supported by the National Natural Science Foundation of China(Grant No.40233033)the Blazing New Trails Program of the Chinese Academy of Sciences(Grant No.ZKCX3-SW-226).
文摘Zonal wind anomaly over the equatorial west- ern Pacific plays an important role in the occurrence of ENSO. The mechanism to produce zonal wind anomaly over the equatorial western Pacific is studied in this paper. It is shown clearly that zonal wind anomaly over the equatorial western Pacific is closely related to the anomaly of East- Asian winter monsoon. Anomalous strong (weak) East-Asian winter monsoon can excite not only the westerly (easterly) anomaly over the equatorial western Pacific but also a cyc- lonic (an anticyclonic) circulation over the east of the Philip- pines. The above anomalous circulation results from dy- namical impacts of anomalous pressure pattern due to the East-Asian winter monsoon. Because there is westward (eastward) pressure gradient over the equatorial western Pacific, i.e. there is ?? xp <0(> 0), during strong (weak) East-Asian winter monsoon.
基金国家重点基础研究发展计划(973计划)，Prediction Theory of Severe Climate Disasters in China，科技部"攀登计划"
文摘By prescribing sea surface temperature anomalies(SSTAs)over eastern equatorial Pacific in January—March,the lag influence of ENSO(El Nino and La Nina)on monsoon over East Asia has been studied.The results suggest that,due to the excitation of atmospheric low-frequency oscillation by the SSTA,ENSO has significant lag influence on the monsoon over East Asia. During the summer after E1 Nino,the subtropical high over western Pacific is intensified and shows the northward and westward displacement,meanwhile,the rainfall over East China is below normal,especially in North China:during the winter after E1 Nino,both the Asian trough and the winter monsoon over East Asia are strengthened.During the summer after La Nina,the anomalous subtropical high prevails over the lower reaches of Yangtze(Changjiang)River,the rainfall between Yangtze and Huaihe Rivers is below normal:during the winter after La Nina, both the Asian trough and the winter monsoon over East Asia are weaker.Compared with La Nina,the effect of El Nino is stronger,but it is not always opposite to the one of La Nina.
