A nested circulation model system based on the Princeton ocean model （POM） is set up to simulate the currentmeter data from a bottom-mounted Acoustic Doppler Profiler （ADP） deployed at the 30 m depth in the Lunan...A nested circulation model system based on the Princeton ocean model （POM） is set up to simulate the currentmeter data from a bottom-mounted Acoustic Doppler Profiler （ADP） deployed at the 30 m depth in the Lunan（South Shandong Province, China） Trough south of the Shandong Peninsula in the summer of 2008, and to study the dynamics of the circulation in the southwestern Huanghai Sea （Yellow Sea）. The model has reproduced well the observed subtidal current at the mooring site. The results of the model simulation suggest that the bottom topography has strong steering effects on the regional circulation in summer. The model simulation shows that the Subei （North Jiangsu Province, China）coastal current flows north- ward in summer, in contrast to the southeastward current in the center of the Lunan Trough measured by the moored currentmeter. The analyses of the model results suggest that the southeastward current at the mooring site in the Lunan Trough is forced by the westward wind-driven current along the Lunan coast, which meets the northward Subei coastal current at the head of the Haizhou Bay to flow along an offshore path in the southeastward direction in the Lunan Trough. Analysis suggests that the Subei coastal current, the Lunan coastal current, and the circulation in the Lunan Trough are independent current systems con- trolled by different dynamics. Therefore, the current measurements in the Lunan Trough cannot be used to represent the Subei coastal current in general.展开更多
The spring of 2018 was the hottest on record since 1951 over eastern China based on station observations,being 2.5°C higher than the 1961−90 mean and with more than 900 stations reaching the record spring mean te...The spring of 2018 was the hottest on record since 1951 over eastern China based on station observations,being 2.5°C higher than the 1961−90 mean and with more than 900 stations reaching the record spring mean temperature.This event exerted serious impacts in the region on agriculture,plant phenology,electricity transmission systems,and human health.In this paper,the contributions of human-induced climate change and anomalous anticyclonic circulation to this event are investigated using the newly homogenized observations and updated Met Office Hadley Centre system for attribution of extreme events,as well as CanESM2(Second Generation Canadian Earth System Model)simulations.Results indicate that both anthropogenic influences and anomalous anticyclonic circulation played significant roles in increasing the probability of the 2018 hottest spring.Quantitative estimates of the probability ratio show that anthropogenic forcing may have increased the chance of this event by ten-fold,while the anomalous circulation increased it by approximately two-fold.The persistent anomalous anticyclonic circulation located on the north side of China blocked the air with lower temperature from high latitudes into eastern China.Without anthropogenic forcing or without the anomalous circulation in northern China,the occurrence probability of the extreme warm spring is significantly reduced.展开更多
In September 2021,southern China witnessed an extreme high-temperature and high-humidity event.The average regional wet bulb globe temperature(WBGT)anomaly(relative to 1961-1990 mean)in 110.0°-120.0°E,27.5&#...In September 2021,southern China witnessed an extreme high-temperature and high-humidity event.The average regional wet bulb globe temperature(WBGT)anomaly(relative to 1961-1990 mean)in 110.0°-120.0°E,27.5°-32.5°N region was the highest on record at 3.28°C and exceeded three times the observed standard deviation.To investigate the underlying causes,we examine the effects of anthropogenic forcings and anomalous circulation patterns on this event using the multi-model ensembles from the Coupled Model Intercomparison Project Phase 6.Results indicate that 2021-like events would happen extremely rarely without anthropogenic warming(would not occur in counterfactual world simulations)and have become a 1-in-16-year event in the factual world.For the threshold of the second most extreme year,the occurrence probability of extreme WBGT events increases approximately 50 times due to the impact of anthropogenic forcings.The effect of anthropogenic warming under similar atmosphere circulation increases the probability of extreme WBGT events by 13-60 times,and that of corresponding circulation patterns under the same anthropogenic warming increases the probability by 1.3-1.8 times.展开更多
A 5-layer numerical model with p-σ incorporated coordinate system and primitive equations is used to simulate the effects of heating anomaly at and over the Tibetan(Qinghai-Xizang)Plateau on the circulations in East ...A 5-layer numerical model with p-σ incorporated coordinate system and primitive equations is used to simulate the effects of heating anomaly at and over the Tibetan(Qinghai-Xizang)Plateau on the circulations in East Asia in sum- mer,The model is described briefly in the text and the results are analysed in somewhat detail.Results show that the sur- face albedo,the drag coefficient,the evaporation rate and the ground temperature all have large influences on the circula- tion near the Plateau and in East Asia.When the heating at the surface increases,the Tibetan high in the upper troposphere intensifies,too.Its area enlarges and its axis tilts to northwest.The upper tropical easterly increase and shifts to north.The southwesterly in the lower troposphere,in consistence,also increases.The cross-equatorial low-lev- el currents along Somali and South India are influenced to increase their speeds while those over North Australia de- crease.The land low over the Asian Continent deepens.Meanwhile the upward motions over the land of east China and over the Indo-China Peninsula intensify and therefore the precipitation over those areas increases.However,along the coastal area of China the upward motions and therefore the precipitation decrease. Atmospheric heat source anomaly has large influence on the circulation,too.Simulated results indicate that heat source anomaly in the lower atmosphere over the Plateau influences the intensity and the position of the monsoon circu- lation while that in the upper atmosphere only affects the intensity.The heating status over the Plateau has slight influ- ence on the westerly jet,north of the Plateau,while it has strong effect on the subtropical jet at the mid and low latitudes.展开更多
The therapeutic effects of activating blood circulation to remove stasis of Chinese medicine （CM） in the prevention and treatment of atherosclerotic diseases such as coronary artery disease and angina are generally ...The therapeutic effects of activating blood circulation to remove stasis of Chinese medicine （CM） in the prevention and treatment of atherosclerotic diseases such as coronary artery disease and angina are generally acknowledged. In recent years, to further improve the therapeutic effects of those Chinese herbs on such diseases, we have carried out a series of studies of CM medications with the function of clearing heat and removing toxic substances combined with activating blood circulation to remove stasis.展开更多
A non-dimensional secondary circulation equation for typhoons has been derived and then 11-yr com- positing typhoon data were used to estimate the thermally forced secondary circulation.The main results have been obta...A non-dimensional secondary circulation equation for typhoons has been derived and then 11-yr com- positing typhoon data were used to estimate the thermally forced secondary circulation.The main results have been obtained as follows: (1)The diabatic heating and Cu vertical heat mixing are major thermal forcing factors.They have the same magnitude of order.(2)The effects of eddy flux and Cu horizontal mixing of heat are of minor im- portance.(3)Ekman pumping and Cu vertical heat mixing cooperatively work.This feedback process is favorable for the enhancement of the secondary circulation of typhoons.展开更多
The present work is intended to simulate, in a rotating annulus of stratified liquid, the me-chanical effect of the Xizang (Tibetan) Plateau on the zonal circulation. The main featuresof three flow patterns around the...The present work is intended to simulate, in a rotating annulus of stratified liquid, the me-chanical effect of the Xizang (Tibetan) Plateau on the zonal circulation. The main featuresof three flow patterns around the plateau for different Rossby number R and rotating Eulernumber E are analysed. and a division diagram of the flow pattern in (R, E) plane is given.It has been found that under the condition that similarity criterions R and E of the experimentalfluid are the same as those existing in the atmosphere for monthly mean states in spring, au-tumn and winter months, the experimental results are satisfied for the following weathersystems over the plateau and its vicinities: the low vortex, trough and shear line over thesoutheast part of the plateau, the tilted ridge over the northwest part of the plateau, the troughpatterns over the upstream and dewnstream of the plateau, the vertical circulation structure, thejets on both north and southeast sides of the plateau, and so on. This shows that the mechanicaleffect of the Tibetan Plateau on the general circulation over East Asia deserves close atten-tion.展开更多
The characteristics and dynamics associated with the distribution, intensity, and triggering factors of local severe precipitation in Zhejiang Province induced by Super Typhoon Soudelor(2015) were investigated using m...The characteristics and dynamics associated with the distribution, intensity, and triggering factors of local severe precipitation in Zhejiang Province induced by Super Typhoon Soudelor(2015) were investigated using mesoscale surface observations, radar reflectivity, satellite nephograms, and the final(FNL) analyses of the Global Forecasting System(GFS) of the National Center for Environmental Prediction(NCEP). The rainfall processes during Soudelor's landfall and translation over East China could be separated into four stages based on rainfall characteristics such as distribution, intensity, and corresponding dynamics. The relatively less precipitation in the first stage resulted from interaction between the easterly wind to the north flank of this tropical cyclone(TC) and the coastal topography along the southeast of Zhejiang Province, China. With landfall of the TC in East China during the second stage, precipitation maxima occurred because of interaction between the TC's principal rainbands and the local topography from northeastern Fujian Province to southwestern Zhejiang Province. The distribution of precipitation presented significant asymmetric features in the third stage with maximal rainfall bands in the northeast quadrant of the TC when Soudelor's track turned from westward to northward as the TC decayed rapidly. Finally, during the northward to northeastward translation of the TC in the fourth stage, the interaction between a mid-latitude weather system and the northern part of the TC resulted in transfer of the maximum rainfall from the north of Zhejiang Province to the north of Jiangsu Province,which represented the end of rainfall in Zhejiang Province. Further quantitative calculations of the rainfall rate induced by the interaction between local topography and TC circulation(defined as "orographic effects") in the context of a one-dimensional simplified model showed that orographic effects were the primary factor determining the intensity of precipitation in this case,and accounted for over 50% of the total precipitation. The asymmetric distribution of the TC's rainbands was closely related to the asymmetric distribution of moisture resulted from changes of the TC's structure, and led to asymmetric distribution of local intense precipitation induced by Soudelor. Based on analysis of this TC, it could be concluded that local severe rainfall in the coastal regions of East China is closely related to changes of TC structure and intensity, as well as the outer rainbands. In addition, precipitation intensity and duration will increase correspondingly because of the complex interactions between the TC and local topography, and the particular TC track along large-scale steering flow. The results of this study may be useful for the understanding, prediction, and warning of disasters induced by local extreme rainfall caused by TCs, especially for facilitating forecasting and warning of flooding and mudslides associated with torrential rain caused by interactions between landfalling TCs and coastal topography.展开更多
基金The 973 Project of China under contract No.2012CB95600the National Natural Science Foundation of China under contract Nos 40888001 and 41176019+1 种基金the Chinese Academy of Sciences under contract No. KZCX2-YW-JS204Qingdao Municipal under contract No.10-3-3-38jh
文摘A nested circulation model system based on the Princeton ocean model （POM） is set up to simulate the currentmeter data from a bottom-mounted Acoustic Doppler Profiler （ADP） deployed at the 30 m depth in the Lunan（South Shandong Province, China） Trough south of the Shandong Peninsula in the summer of 2008, and to study the dynamics of the circulation in the southwestern Huanghai Sea （Yellow Sea）. The model has reproduced well the observed subtidal current at the mooring site. The results of the model simulation suggest that the bottom topography has strong steering effects on the regional circulation in summer. The model simulation shows that the Subei （North Jiangsu Province, China）coastal current flows north- ward in summer, in contrast to the southeastward current in the center of the Lunan Trough measured by the moored currentmeter. The analyses of the model results suggest that the southeastward current at the mooring site in the Lunan Trough is forced by the westward wind-driven current along the Lunan coast, which meets the northward Subei coastal current at the head of the Haizhou Bay to flow along an offshore path in the southeastward direction in the Lunan Trough. Analysis suggests that the Subei coastal current, the Lunan coastal current, and the circulation in the Lunan Trough are independent current systems con- trolled by different dynamics. Therefore, the current measurements in the Lunan Trough cannot be used to represent the Subei coastal current in general.
基金the National Key Research and Development Program of China(Grant No.2018YFC1507702)the National Natural Science Foundation of China(Grant No.41775082)+3 种基金Y.SUN was supported by the National Key Research and Development Program of China(Grant No.2016YFA0600701)the National Natural Science Foundation of China(Grant No.41790471)N.CHRISTIDIS and P.A.STOTT were supported by the Met Office Hadley Centre Climate Programme funded by BEIS,Defrathe UK−China Research and Innovation Partnership Fund through the Met Office Climate Science for Service Partnership(CSSP)China as part of the Newton Fund,China.
文摘The spring of 2018 was the hottest on record since 1951 over eastern China based on station observations,being 2.5°C higher than the 1961−90 mean and with more than 900 stations reaching the record spring mean temperature.This event exerted serious impacts in the region on agriculture,plant phenology,electricity transmission systems,and human health.In this paper,the contributions of human-induced climate change and anomalous anticyclonic circulation to this event are investigated using the newly homogenized observations and updated Met Office Hadley Centre system for attribution of extreme events,as well as CanESM2(Second Generation Canadian Earth System Model)simulations.Results indicate that both anthropogenic influences and anomalous anticyclonic circulation played significant roles in increasing the probability of the 2018 hottest spring.Quantitative estimates of the probability ratio show that anthropogenic forcing may have increased the chance of this event by ten-fold,while the anomalous circulation increased it by approximately two-fold.The persistent anomalous anticyclonic circulation located on the north side of China blocked the air with lower temperature from high latitudes into eastern China.Without anthropogenic forcing or without the anomalous circulation in northern China,the occurrence probability of the extreme warm spring is significantly reduced.
基金National Natural Science Foundation of China(42025503)National Key Research and Development Program of China(2018YFA0605604)。
文摘In September 2021,southern China witnessed an extreme high-temperature and high-humidity event.The average regional wet bulb globe temperature(WBGT)anomaly(relative to 1961-1990 mean)in 110.0°-120.0°E,27.5°-32.5°N region was the highest on record at 3.28°C and exceeded three times the observed standard deviation.To investigate the underlying causes,we examine the effects of anthropogenic forcings and anomalous circulation patterns on this event using the multi-model ensembles from the Coupled Model Intercomparison Project Phase 6.Results indicate that 2021-like events would happen extremely rarely without anthropogenic warming(would not occur in counterfactual world simulations)and have become a 1-in-16-year event in the factual world.For the threshold of the second most extreme year,the occurrence probability of extreme WBGT events increases approximately 50 times due to the impact of anthropogenic forcings.The effect of anthropogenic warming under similar atmosphere circulation increases the probability of extreme WBGT events by 13-60 times,and that of corresponding circulation patterns under the same anthropogenic warming increases the probability by 1.3-1.8 times.
文摘A 5-layer numerical model with p-σ incorporated coordinate system and primitive equations is used to simulate the effects of heating anomaly at and over the Tibetan(Qinghai-Xizang)Plateau on the circulations in East Asia in sum- mer,The model is described briefly in the text and the results are analysed in somewhat detail.Results show that the sur- face albedo,the drag coefficient,the evaporation rate and the ground temperature all have large influences on the circula- tion near the Plateau and in East Asia.When the heating at the surface increases,the Tibetan high in the upper troposphere intensifies,too.Its area enlarges and its axis tilts to northwest.The upper tropical easterly increase and shifts to north.The southwesterly in the lower troposphere,in consistence,also increases.The cross-equatorial low-lev- el currents along Somali and South India are influenced to increase their speeds while those over North Australia de- crease.The land low over the Asian Continent deepens.Meanwhile the upward motions over the land of east China and over the Indo-China Peninsula intensify and therefore the precipitation over those areas increases.However,along the coastal area of China the upward motions and therefore the precipitation decrease. Atmospheric heat source anomaly has large influence on the circulation,too.Simulated results indicate that heat source anomaly in the lower atmosphere over the Plateau influences the intensity and the position of the monsoon circu- lation while that in the upper atmosphere only affects the intensity.The heating status over the Plateau has slight influ- ence on the westerly jet,north of the Plateau,while it has strong effect on the subtropical jet at the mid and low latitudes.
文摘The therapeutic effects of activating blood circulation to remove stasis of Chinese medicine （CM） in the prevention and treatment of atherosclerotic diseases such as coronary artery disease and angina are generally acknowledged. In recent years, to further improve the therapeutic effects of those Chinese herbs on such diseases, we have carried out a series of studies of CM medications with the function of clearing heat and removing toxic substances combined with activating blood circulation to remove stasis.
文摘A non-dimensional secondary circulation equation for typhoons has been derived and then 11-yr com- positing typhoon data were used to estimate the thermally forced secondary circulation.The main results have been obtained as follows: (1)The diabatic heating and Cu vertical heat mixing are major thermal forcing factors.They have the same magnitude of order.(2)The effects of eddy flux and Cu horizontal mixing of heat are of minor im- portance.(3)Ekman pumping and Cu vertical heat mixing cooperatively work.This feedback process is favorable for the enhancement of the secondary circulation of typhoons.
文摘The present work is intended to simulate, in a rotating annulus of stratified liquid, the me-chanical effect of the Xizang (Tibetan) Plateau on the zonal circulation. The main featuresof three flow patterns around the plateau for different Rossby number R and rotating Eulernumber E are analysed. and a division diagram of the flow pattern in (R, E) plane is given.It has been found that under the condition that similarity criterions R and E of the experimentalfluid are the same as those existing in the atmosphere for monthly mean states in spring, au-tumn and winter months, the experimental results are satisfied for the following weathersystems over the plateau and its vicinities: the low vortex, trough and shear line over thesoutheast part of the plateau, the tilted ridge over the northwest part of the plateau, the troughpatterns over the upstream and dewnstream of the plateau, the vertical circulation structure, thejets on both north and southeast sides of the plateau, and so on. This shows that the mechanicaleffect of the Tibetan Plateau on the general circulation over East Asia deserves close atten-tion.
基金supported by the Huadong Regional Meteorological Science and Technology Innovation Fund Collaborative Project (Grant No. QYHZ201404)the Development of Social Welfare Project of Zhejiang Province (Grant No. 2013C33037)+2 种基金the Science Foundation of Zhejiang Province (Grant No. LY18D050001)United States Office of Naval Research Project (Grant No. N000140910526)the Development of Social Welfare Key Project of Zhejiang Province (Grant No. 2017C03035)
文摘The characteristics and dynamics associated with the distribution, intensity, and triggering factors of local severe precipitation in Zhejiang Province induced by Super Typhoon Soudelor(2015) were investigated using mesoscale surface observations, radar reflectivity, satellite nephograms, and the final(FNL) analyses of the Global Forecasting System(GFS) of the National Center for Environmental Prediction(NCEP). The rainfall processes during Soudelor's landfall and translation over East China could be separated into four stages based on rainfall characteristics such as distribution, intensity, and corresponding dynamics. The relatively less precipitation in the first stage resulted from interaction between the easterly wind to the north flank of this tropical cyclone(TC) and the coastal topography along the southeast of Zhejiang Province, China. With landfall of the TC in East China during the second stage, precipitation maxima occurred because of interaction between the TC's principal rainbands and the local topography from northeastern Fujian Province to southwestern Zhejiang Province. The distribution of precipitation presented significant asymmetric features in the third stage with maximal rainfall bands in the northeast quadrant of the TC when Soudelor's track turned from westward to northward as the TC decayed rapidly. Finally, during the northward to northeastward translation of the TC in the fourth stage, the interaction between a mid-latitude weather system and the northern part of the TC resulted in transfer of the maximum rainfall from the north of Zhejiang Province to the north of Jiangsu Province,which represented the end of rainfall in Zhejiang Province. Further quantitative calculations of the rainfall rate induced by the interaction between local topography and TC circulation(defined as "orographic effects") in the context of a one-dimensional simplified model showed that orographic effects were the primary factor determining the intensity of precipitation in this case,and accounted for over 50% of the total precipitation. The asymmetric distribution of the TC's rainbands was closely related to the asymmetric distribution of moisture resulted from changes of the TC's structure, and led to asymmetric distribution of local intense precipitation induced by Soudelor. Based on analysis of this TC, it could be concluded that local severe rainfall in the coastal regions of East China is closely related to changes of TC structure and intensity, as well as the outer rainbands. In addition, precipitation intensity and duration will increase correspondingly because of the complex interactions between the TC and local topography, and the particular TC track along large-scale steering flow. The results of this study may be useful for the understanding, prediction, and warning of disasters induced by local extreme rainfall caused by TCs, especially for facilitating forecasting and warning of flooding and mudslides associated with torrential rain caused by interactions between landfalling TCs and coastal topography.
