It is of practical significance to use the updated Coupled Model Intercomparison Project Phase 6(CMIP6)models to study the impact of changes in land‒sea thermodynamic contrast(TC)on the Asian summer monsoon under diff...It is of practical significance to use the updated Coupled Model Intercomparison Project Phase 6(CMIP6)models to study the impact of changes in land‒sea thermodynamic contrast(TC)on the Asian summer monsoon under different scenarios and to compare the similarities and differences of the impact mechanisms between different monsoon regions.In this study,we investigated future changes of the Asian summer monsoon under four Shared Socioeconomic Pathway(SSP)scenarios using 19 CMIP6 models.The intensity of the South Asian summer monsoon(SASM)is projected to decrease by 2.6%,6.3%,10.1%,and 11.1%,while the East Asian summer monsoon(EASM)intensity is projected to increase by 4.6%,7.9%,7.4%,and 9.8%until the end of the 21st century for SSP126,SSP245,SSP370,and SSP585 scenarios,respectively.Moreover,summer precipitation in Asia is projected to increase remarkably in 2015-2099 under all four scenarios.The inconsistent warming trends over the Tibetan Plateau(TP),Northwest Pacific,and tropical Indian Ocean would greatly impact the monsoon circulations.The upper-troposphere warming trend over the surrounding oceans is remarkably greater than that over the TP,while the near-surface warming trend over the surrounding oceans is smaller than that over the TP.The decrease of upper-troposphere TC between the TP and tropical Indian Ocean results in a weakening of the SASM circulation.The enhancement of the lower-troposphere TC between the TP and Northwest Pacific would strengthen the EASM circulation.Moisture budget analysis shows that the water-vapor would increase in the future,which would thermodynamically enhance summer precipitation through the anomalous vertical moisture transport associated with mean flow.The strengthening of the meridional circulation of the EASM would increase monsoon precipitation,while the weakening of zonal circulation of the SASM would dynamically reduce South Asian summer precipitation.展开更多
PSU / NCAR MM5 was utilized to simulate the sea-land breeze circulation in Macao and the three-dimensional flow around the Pearl River estuary. Four two-way nested grids having resolution of 1, 3, 9, and 27 km were in...PSU / NCAR MM5 was utilized to simulate the sea-land breeze circulation in Macao and the three-dimensional flow around the Pearl River estuary. Four two-way nested grids having resolution of 1, 3, 9, and 27 km were included in the simulation. It was initialized with conventional observational data, and a 30 h simulation and analysis of one sea-land breeze case were performed. It was shown, that the model with a finer resolution (1 km) captures the sea breeze and land breeze in Macao with reasonable skill. The sea breeze front and the thermal internal boundary layer (TIBL) were also obviously revealed. However, the coarser horizontal resolution (3 km) could capture the sea breeze but not the land breeze.展开更多
In this work, the SCSMEX data are used to diagnose and compare the local land-sea thermal conditions, with the focus of discussion on possible influences of thermal forcing of the western Pacific and the Tibetan Plate...In this work, the SCSMEX data are used to diagnose and compare the local land-sea thermal conditions, with the focus of discussion on possible influences of thermal forcing of the western Pacific and the Tibetan Plateau on the onset and development of summer monsoon in 1998. Results show a close relationship between the distribution of the heat sources and the land-sea contrast. Due to the blocking effect of terrain, main maximum zones of the heat sources in areas with more evident north-south land-sea contrast are more obviously southward located than those exclusively with oceans. The surface heating is characterized with apparent seasonal variation and difference between land and sea. The relationship between the western Pacific and the onset of summer monsoon is reflected in the variations of the sea surface temperature (SST) and the latent heat. The influence mechanism of the Tibetan Plateau during the summer monsoon is different: it is dominated by sensible heating during the South China Sea monsoon and by condensed latent heating during the Indian monsoon.展开更多
An analytic study of the structure of sea-land breezes is presented, with special attention paid to the dependence on the model parameters. In this linearized model, the wind speed of the sea-land breezes is directly ...An analytic study of the structure of sea-land breezes is presented, with special attention paid to the dependence on the model parameters. In this linearized model, the wind speed of the sea-land breezes is directly proportional to the difference of sea and land heating rates. For the same differential heating, the sea-land breeze is more prominent if the stratification is weakly stable, or if the frictional force is small. The horizontal penetration from the coast is also investigated, and found to be asymmetric between the land and the sea. The above results are in agreement with observation.展开更多
A number of AGCM simulations were performed by including various land–sea distributions （LSDs）, such as meridional LSDs, zonal LSDs, tropical large-scale LSDs, and subcontinental-scale LSDs, to identify their effec...A number of AGCM simulations were performed by including various land–sea distributions （LSDs）, such as meridional LSDs, zonal LSDs, tropical large-scale LSDs, and subcontinental-scale LSDs, to identify their effects on the Asian monsoon. In seven meridional LSD experiments with the continent/ocean located to the north/south of a certain latitude, the LSDs remain identical except the southern coastline is varied from 40 ° to 4 ° N in intervals of 5.6° . In the experiments with the coastline located to the north of 21° N, no monsoon can be found in the subtropical zone. In contrast, a summer monsoon is simulated when the continent extends to the south of 21 ° N. Meanwhile, the earlier onset and stronger intensity of the tropical summer monsoon are simulated with the southward extension of the tropical continent. The effects of zonal LSDs were investigated by including the Pacific and Atlantic Ocean into the model based on the meridional LSD run with the coastline located at 21 °N. The results indicate that the presence of a mid-latitude zonal LSD induces a strong zonal pressure gradient between the continent and ocean, which in turn results in the formation of an East Asian subtropical monsoon. The comparison of simulations with and without the Indian Peninsula and Indo-China Peninsula reveals that the presence of two peninsulas remarkably strengthens the southwesterly winds over South Asia due to the tropical asymmetric heating between the tropical land and sea. The tropical zonal LSD plays a crucial role in the formation of cumulus convection.展开更多
Analyzed in this paper are the influencing factors, characteristics, and mechanism of land-sea interaction for the Taihu Lake Basin. The course of mass movement and energy transformation between land and sea in the Ta...Analyzed in this paper are the influencing factors, characteristics, and mechanism of land-sea interaction for the Taihu Lake Basin. The course of mass movement and energy transformation between land and sea in the Taihu Lake Basin has experienced three different stages, namely, ocean predominance, balance between land and sea, and land predominance. In the paper the process of the formation and the evolution of the Taihu Lake is studied considering the land-sea interaction.展开更多
The effects of the land-sea distribution, the topography and the diurnal change of the solar radiation on the summer monsoon modelings are studied by use of a coupled modeling system with a 5-layer primitive equation ...The effects of the land-sea distribution, the topography and the diurnal change of the solar radiation on the summer monsoon modelings are studied by use of a coupled modeling system with a 5-layer primitive equation model of the atmosphere and a 2-layer soil or ocean thermodynamic model which are all solved in a zonal model domain between 60°S and 60°N. The results of numerical simulations show that the quasi-stationary patterns of the mean monsoon circulations are mainly affected by the land-sea distribution and the topography, the effect of the diurnal change is the secondary. However, the inclusion of the diurnal change into the model system may improve the intensity of the simulated monsoon circulation, it can influence the distributive pattern of precipitation to a larger extent,without the diurnal change precipitation in the interior of land would decrease and in the coastal regions it would increase.展开更多
The effects of the land-sea contrast and the topography on the climatic properties are simulated rn this paper by use of a p- a incorporated coordinate system mode! in a zonal domain.In this paper we firstly discuss t...The effects of the land-sea contrast and the topography on the climatic properties are simulated rn this paper by use of a p- a incorporated coordinate system mode! in a zonal domain.In this paper we firstly discuss the statistical features of the model and find that the capability of the model is stable,with the same land-sea distribution and topography seven monthly mean climate states are close to one another,their variance is even less than the initial one.Secondly,we focally discuss the effects of the land-sea contrast and the topography on the modeled climate fields.It is pointed out that the land-sea contrast and the topography influence the atmosphere mainly through the heating ef-fect and the former has larger influences on the simulated large scale climate fields than the latter.展开更多
Based on the data analysis, this study further explores the characteristics of East Asian winter monsoon (hereafter, EAWM, for brevity) as well as the related air-sea-land system, and illustrates how and to what degre...Based on the data analysis, this study further explores the characteristics of East Asian winter monsoon (hereafter, EAWM, for brevity) as well as the related air-sea-land system, and illustrates how and to what degree anomalous signals of the subsequent Asian summer monsoon are rooted in the preceding EAWM activity. We identified an important air-sea coupled mode, i.e., the EAWM mode illustrated in Section 3. In cold seasons, strong EAWM-related air-sea two-way interaction is responsible for the development and persistence of the SSTA pattern of EAWM mode. As a consequence, the key regions, i.e., the western Pacific and South China Sea (hereafter, SCS, for brevity), are dominated by such an SSTA pattern from the winter to the following summer. In the strong EAWM years, the deficient snow cover dominates eastern Tibetan Plateau in winter, and in spring, this anomaly pattern is further strengthened and extended to the northwestern side of Tibetan Plateau. Thus, the combined effect of strong EAWM-related SSTA and Tibetan snow cover constitutes an important factor in modulating the Asian monsoon circulation. The active role of the EAWM activity as well as the related air-sea-land interaction would, in the subsequent seasons, lead to: 1) the enhancement of SCS monsoon and related stronger rainfall; 2) the northward displacement of subtropical high during Meiyu period and the related deficient rainfall over Meiyu rainband; 3) above-normal precipitation over the regions from northern Japan to northeastern China in summer; 4) more rainfall over the Arabian Sea and Northeast India, while less rainfall over southwest India and the Bay of Bengal. The strong EAWM-related air-sea interaction shows, to some degree, precursory signals to the following Asian summer monsoon. However, the mechanism for the variability of Indian summer monsoon subsequent to the strong EAWM years remains uncertain.展开更多
Four automatic meteorological stations were set up in a line from beach to inland perpendicular to the west coast of Bohai Bay. Wind direction and velocity at altitudes of 2 m, 4 m and 12 m were surveyed with 10 minut...Four automatic meteorological stations were set up in a line from beach to inland perpendicular to the west coast of Bohai Bay. Wind direction and velocity at altitudes of 2 m, 4 m and 12 m were surveyed with 10 minute intervals. On ＂Sea-Land Breeze＂ （SLB） days, the transition from sea breeze to land breeze was very evident in the study area. Direction of sea breeze was basically perpendicular to the coast and mainly from the ENE and E. Duration of sea breeze varied by the stations＇ distance to the coastline, and the near-coast wind velocity was larger than that of the inland and decreases as it reaches inland. There was increased development of SLB on sunny days than on overcast days. The term ＂Climatic Coastal Zone＂ can be defined for the area influenced by SLB, which reaches more than 74 km inland on a typical SLB day but less than 10 km on a non-typical SLB day.展开更多
Based on some experts’ research effort, the problems of land subsidence and relative sea level rise in three Chinese delta areas (Huanghe, Changjiang and Zhujiang Delta) are analyzed and discussed in this paper. The ...Based on some experts’ research effort, the problems of land subsidence and relative sea level rise in three Chinese delta areas (Huanghe, Changjiang and Zhujiang Delta) are analyzed and discussed in this paper. The authors’ opinion is that the land subsidence is mainly induced by human activity and has made the greater contributions to the relative sea level rise and become one of the geological hazards in these areas. In Tianjin and Shanghai areas where had ever existed serious land subsidence problem, due to the positive and effective control methods, the ratio of man-induced land subsidence to relative sea level rise decreased from 80%-90% in 1960s-1970s to less than 60% at present. But it is estimated that in the next tens of years this ratio will still be considerable. So human being must keep its eyes on this phenomenon and take more positive countermeasures to control the land subsidence.展开更多
Based on the NCEP/NCAR reanalysis data for the period of 1948-2004 and the monthly rainfall data at 160 stations in China from 1951 to 2004, the relationships among the land-ocean temperature anomaly difference in the...Based on the NCEP/NCAR reanalysis data for the period of 1948-2004 and the monthly rainfall data at 160 stations in China from 1951 to 2004, the relationships among the land-ocean temperature anomaly difference in the mid-lower troposphere in spring （April-May）, the mei-yu rainfall in the Yangtze River- Huaihe River basin, and the activities of the South China Sea summer monsoon （SCSSM） are analyzed by using correlation and composite analyses. Results show that a significant positive correlation exists between mei-yu rainfall and air temperature in the middle latitudes above the western Pacific, while a significant negative correlation is located to the southwest of the Baikal Lake. When the land-ocean thermal anomaly difference is stronger in spring, the western Pacific subtropical high （WPSH） will be weaker and retreat eastward in summer （June-July）, and the SCSSM will be stronger and advance further north, resulting in deficient moisture along the mei-yu front and below-normal precipitation in the mid and lower reaches of the Yangtze River, and vice versa for the weaker difference case. The effects and relative importance of the land and ocean anomalous heating on monsoon variability is also compared. It is found that the land and ocean thermal anomalies are both closely related to the summer circulation and mei-yu rainfall and SCSSM intensity, whereas the land heating anomaly is more important than ocean heating in changing the land-ocean thermal contrast and hence the summer monsoon intensity.展开更多
The influence of land based source pollutants to marine ecological environment is principally in coastal or enclosed sea waters. Flux of land based source pollutants into the sea will be effected due to social and ...The influence of land based source pollutants to marine ecological environment is principally in coastal or enclosed sea waters. Flux of land based source pollutants into the sea will be effected due to social and economic development in the Tumen River basin. Pollutant type and primary pollution factor of the Tumen River in Northeast China is described by weighted coefficient method in this paper. The results indicate that the river is organic pollution type and primary pollution factor is COD. Fresh water fraction proves that the estuary is not affected by tide cycle. COD annual flux entering the Sea of Japan calculated by zero dimension model in 1993 was 90.50 ×10 3 tons. It is estimated with emission coefficient method that the COD will be 176.4 ×10 3 and 458.6 ×10 3 tons for the years of 2000 and 2010 respectively.展开更多
基金funded by the Second Tibetan Plateau Scientific Expedition and Research Program of China(2019QZKK0208)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20100304)+1 种基金the National Natural Science Foundation of China(41790471)the National Key Research and Development Program of China(2016YFA0602200,2019YFC1510400).
文摘It is of practical significance to use the updated Coupled Model Intercomparison Project Phase 6(CMIP6)models to study the impact of changes in land‒sea thermodynamic contrast(TC)on the Asian summer monsoon under different scenarios and to compare the similarities and differences of the impact mechanisms between different monsoon regions.In this study,we investigated future changes of the Asian summer monsoon under four Shared Socioeconomic Pathway(SSP)scenarios using 19 CMIP6 models.The intensity of the South Asian summer monsoon(SASM)is projected to decrease by 2.6%,6.3%,10.1%,and 11.1%,while the East Asian summer monsoon(EASM)intensity is projected to increase by 4.6%,7.9%,7.4%,and 9.8%until the end of the 21st century for SSP126,SSP245,SSP370,and SSP585 scenarios,respectively.Moreover,summer precipitation in Asia is projected to increase remarkably in 2015-2099 under all four scenarios.The inconsistent warming trends over the Tibetan Plateau(TP),Northwest Pacific,and tropical Indian Ocean would greatly impact the monsoon circulations.The upper-troposphere warming trend over the surrounding oceans is remarkably greater than that over the TP,while the near-surface warming trend over the surrounding oceans is smaller than that over the TP.The decrease of upper-troposphere TC between the TP and tropical Indian Ocean results in a weakening of the SASM circulation.The enhancement of the lower-troposphere TC between the TP and Northwest Pacific would strengthen the EASM circulation.Moisture budget analysis shows that the water-vapor would increase in the future,which would thermodynamically enhance summer precipitation through the anomalous vertical moisture transport associated with mean flow.The strengthening of the meridional circulation of the EASM would increase monsoon precipitation,while the weakening of zonal circulation of the SASM would dynamically reduce South Asian summer precipitation.
基金This research is jointly supported by the grant of the Chinese State Commission of ScienceTechnology Climbing A " SCSMEX"
文摘PSU / NCAR MM5 was utilized to simulate the sea-land breeze circulation in Macao and the three-dimensional flow around the Pearl River estuary. Four two-way nested grids having resolution of 1, 3, 9, and 27 km were included in the simulation. It was initialized with conventional observational data, and a 30 h simulation and analysis of one sea-land breeze case were performed. It was shown, that the model with a finer resolution (1 km) captures the sea breeze and land breeze in Macao with reasonable skill. The sea breeze front and the thermal internal boundary layer (TIBL) were also obviously revealed. However, the coarser horizontal resolution (3 km) could capture the sea breeze but not the land breeze.
基金 Part I: Research on the Formation Mechnism and Prediction Theory of Severe Climate Disasters in China (G199804900) 揂nalysis and Mechanism Study of Regional Climate Changes in China? a key projec
文摘In this work, the SCSMEX data are used to diagnose and compare the local land-sea thermal conditions, with the focus of discussion on possible influences of thermal forcing of the western Pacific and the Tibetan Plateau on the onset and development of summer monsoon in 1998. Results show a close relationship between the distribution of the heat sources and the land-sea contrast. Due to the blocking effect of terrain, main maximum zones of the heat sources in areas with more evident north-south land-sea contrast are more obviously southward located than those exclusively with oceans. The surface heating is characterized with apparent seasonal variation and difference between land and sea. The relationship between the western Pacific and the onset of summer monsoon is reflected in the variations of the sea surface temperature (SST) and the latent heat. The influence mechanism of the Tibetan Plateau during the summer monsoon is different: it is dominated by sensible heating during the South China Sea monsoon and by condensed latent heating during the Indian monsoon.
文摘An analytic study of the structure of sea-land breezes is presented, with special attention paid to the dependence on the model parameters. In this linearized model, the wind speed of the sea-land breezes is directly proportional to the difference of sea and land heating rates. For the same differential heating, the sea-land breeze is more prominent if the stratification is weakly stable, or if the frictional force is small. The horizontal penetration from the coast is also investigated, and found to be asymmetric between the land and the sea. The above results are in agreement with observation.
基金supported jointly by the "National Key Developing Programme for Basic Science" project 2006CB400500China Postdoctoral Science Foundation 20070410133National Natural Science Foundation of China General Program 40905042, and 40675042
文摘A number of AGCM simulations were performed by including various land–sea distributions （LSDs）, such as meridional LSDs, zonal LSDs, tropical large-scale LSDs, and subcontinental-scale LSDs, to identify their effects on the Asian monsoon. In seven meridional LSD experiments with the continent/ocean located to the north/south of a certain latitude, the LSDs remain identical except the southern coastline is varied from 40 ° to 4 ° N in intervals of 5.6° . In the experiments with the coastline located to the north of 21° N, no monsoon can be found in the subtropical zone. In contrast, a summer monsoon is simulated when the continent extends to the south of 21 ° N. Meanwhile, the earlier onset and stronger intensity of the tropical summer monsoon are simulated with the southward extension of the tropical continent. The effects of zonal LSDs were investigated by including the Pacific and Atlantic Ocean into the model based on the meridional LSD run with the coastline located at 21 °N. The results indicate that the presence of a mid-latitude zonal LSD induces a strong zonal pressure gradient between the continent and ocean, which in turn results in the formation of an East Asian subtropical monsoon. The comparison of simulations with and without the Indian Peninsula and Indo-China Peninsula reveals that the presence of two peninsulas remarkably strengthens the southwesterly winds over South Asia due to the tropical asymmetric heating between the tropical land and sea. The tropical zonal LSD plays a crucial role in the formation of cumulus convection.
基金This work was financially supported by Science and Technology Innovation Fund of Ministry of Water Resources ofChina (Grant No.SCX2004-03)
文摘Analyzed in this paper are the influencing factors, characteristics, and mechanism of land-sea interaction for the Taihu Lake Basin. The course of mass movement and energy transformation between land and sea in the Taihu Lake Basin has experienced three different stages, namely, ocean predominance, balance between land and sea, and land predominance. In the paper the process of the formation and the evolution of the Taihu Lake is studied considering the land-sea interaction.
文摘The effects of the land-sea distribution, the topography and the diurnal change of the solar radiation on the summer monsoon modelings are studied by use of a coupled modeling system with a 5-layer primitive equation model of the atmosphere and a 2-layer soil or ocean thermodynamic model which are all solved in a zonal model domain between 60°S and 60°N. The results of numerical simulations show that the quasi-stationary patterns of the mean monsoon circulations are mainly affected by the land-sea distribution and the topography, the effect of the diurnal change is the secondary. However, the inclusion of the diurnal change into the model system may improve the intensity of the simulated monsoon circulation, it can influence the distributive pattern of precipitation to a larger extent,without the diurnal change precipitation in the interior of land would decrease and in the coastal regions it would increase.
基金Supported by the National Key Project of Fundamental Research "Climate DynamicsClimate Prediction Theory"the National Natural Science Foundation of China
文摘The effects of the land-sea contrast and the topography on the climatic properties are simulated rn this paper by use of a p- a incorporated coordinate system mode! in a zonal domain.In this paper we firstly discuss the statistical features of the model and find that the capability of the model is stable,with the same land-sea distribution and topography seven monthly mean climate states are close to one another,their variance is even less than the initial one.Secondly,we focally discuss the effects of the land-sea contrast and the topography on the modeled climate fields.It is pointed out that the land-sea contrast and the topography influence the atmosphere mainly through the heating ef-fect and the former has larger influences on the simulated large scale climate fields than the latter.
基金This work was jointly supported by Key Project of Chinese Academy of Sciences (KZCX2-203), Na-tional Natural Science Foundatio
文摘Based on the data analysis, this study further explores the characteristics of East Asian winter monsoon (hereafter, EAWM, for brevity) as well as the related air-sea-land system, and illustrates how and to what degree anomalous signals of the subsequent Asian summer monsoon are rooted in the preceding EAWM activity. We identified an important air-sea coupled mode, i.e., the EAWM mode illustrated in Section 3. In cold seasons, strong EAWM-related air-sea two-way interaction is responsible for the development and persistence of the SSTA pattern of EAWM mode. As a consequence, the key regions, i.e., the western Pacific and South China Sea (hereafter, SCS, for brevity), are dominated by such an SSTA pattern from the winter to the following summer. In the strong EAWM years, the deficient snow cover dominates eastern Tibetan Plateau in winter, and in spring, this anomaly pattern is further strengthened and extended to the northwestern side of Tibetan Plateau. Thus, the combined effect of strong EAWM-related SSTA and Tibetan snow cover constitutes an important factor in modulating the Asian monsoon circulation. The active role of the EAWM activity as well as the related air-sea-land interaction would, in the subsequent seasons, lead to: 1) the enhancement of SCS monsoon and related stronger rainfall; 2) the northward displacement of subtropical high during Meiyu period and the related deficient rainfall over Meiyu rainband; 3) above-normal precipitation over the regions from northern Japan to northeastern China in summer; 4) more rainfall over the Arabian Sea and Northeast India, while less rainfall over southwest India and the Bay of Bengal. The strong EAWM-related air-sea interaction shows, to some degree, precursory signals to the following Asian summer monsoon. However, the mechanism for the variability of Indian summer monsoon subsequent to the strong EAWM years remains uncertain.
基金supported by National Science & Technology Support Key Project of China (No.2006BAB03A03)National 863 Key Project of China (No.2006AA100206)National Natural Science Foundation Projects of China(No.40801230 and No.40335048)
文摘Four automatic meteorological stations were set up in a line from beach to inland perpendicular to the west coast of Bohai Bay. Wind direction and velocity at altitudes of 2 m, 4 m and 12 m were surveyed with 10 minute intervals. On ＂Sea-Land Breeze＂ （SLB） days, the transition from sea breeze to land breeze was very evident in the study area. Direction of sea breeze was basically perpendicular to the coast and mainly from the ENE and E. Duration of sea breeze varied by the stations＇ distance to the coastline, and the near-coast wind velocity was larger than that of the inland and decreases as it reaches inland. There was increased development of SLB on sunny days than on overcast days. The term ＂Climatic Coastal Zone＂ can be defined for the area influenced by SLB, which reaches more than 74 km inland on a typical SLB day but less than 10 km on a non-typical SLB day.
文摘Based on some experts’ research effort, the problems of land subsidence and relative sea level rise in three Chinese delta areas (Huanghe, Changjiang and Zhujiang Delta) are analyzed and discussed in this paper. The authors’ opinion is that the land subsidence is mainly induced by human activity and has made the greater contributions to the relative sea level rise and become one of the geological hazards in these areas. In Tianjin and Shanghai areas where had ever existed serious land subsidence problem, due to the positive and effective control methods, the ratio of man-induced land subsidence to relative sea level rise decreased from 80%-90% in 1960s-1970s to less than 60% at present. But it is estimated that in the next tens of years this ratio will still be considerable. So human being must keep its eyes on this phenomenon and take more positive countermeasures to control the land subsidence.
基金supported by the National Basic Research Program ofChina (Grant No. 2004CB418300)the National Natural Science Foundation of China (Grant No. 40675042)
文摘Based on the NCEP/NCAR reanalysis data for the period of 1948-2004 and the monthly rainfall data at 160 stations in China from 1951 to 2004, the relationships among the land-ocean temperature anomaly difference in the mid-lower troposphere in spring （April-May）, the mei-yu rainfall in the Yangtze River- Huaihe River basin, and the activities of the South China Sea summer monsoon （SCSSM） are analyzed by using correlation and composite analyses. Results show that a significant positive correlation exists between mei-yu rainfall and air temperature in the middle latitudes above the western Pacific, while a significant negative correlation is located to the southwest of the Baikal Lake. When the land-ocean thermal anomaly difference is stronger in spring, the western Pacific subtropical high （WPSH） will be weaker and retreat eastward in summer （June-July）, and the SCSSM will be stronger and advance further north, resulting in deficient moisture along the mei-yu front and below-normal precipitation in the mid and lower reaches of the Yangtze River, and vice versa for the weaker difference case. The effects and relative importance of the land and ocean anomalous heating on monsoon variability is also compared. It is found that the land and ocean thermal anomalies are both closely related to the summer circulation and mei-yu rainfall and SCSSM intensity, whereas the land heating anomaly is more important than ocean heating in changing the land-ocean thermal contrast and hence the summer monsoon intensity.
文摘The influence of land based source pollutants to marine ecological environment is principally in coastal or enclosed sea waters. Flux of land based source pollutants into the sea will be effected due to social and economic development in the Tumen River basin. Pollutant type and primary pollution factor of the Tumen River in Northeast China is described by weighted coefficient method in this paper. The results indicate that the river is organic pollution type and primary pollution factor is COD. Fresh water fraction proves that the estuary is not affected by tide cycle. COD annual flux entering the Sea of Japan calculated by zero dimension model in 1993 was 90.50 ×10 3 tons. It is estimated with emission coefficient method that the COD will be 176.4 ×10 3 and 458.6 ×10 3 tons for the years of 2000 and 2010 respectively.
