The following six aspects in the utilization of lake resources and progress of limnological research in China are described : 1 . Expeditions for comprehensive investigation of lakes ; 2 . Physical limnology; 3 . Lacu...The following six aspects in the utilization of lake resources and progress of limnological research in China are described : 1 . Expeditions for comprehensive investigation of lakes ; 2 . Physical limnology; 3 . Lacustrine sedimentology and paleolimnology ; 4 . Hydrobiology and ecology ; 5 . Hydrochemistry and environmental protection; 6 . Development and utilization of lake resources.展开更多
The rapid shrinkage of the surface area reflects the long-term deficit water budget of Qinghai Lake. Study of the yearly hydrology and meteorology in the lake catchment basin and the hydrologic factors as well as wate...The rapid shrinkage of the surface area reflects the long-term deficit water budget of Qinghai Lake. Study of the yearly hydrology and meteorology in the lake catchment basin and the hydrologic factors as well as water budget led to the conclusion that evaporation exceeding the water input resulted in the drop of lake level, thai the obvious decrease of runoff to the lake and precipitation on the catchment accelerated the falling of lake level before 1987. and that increase of about 6.7% in rainfall on the whole basin will balance the lake’s water budget.展开更多
Qinghai Lake is located in a hydrologically closed basin at the conjunction of SE and SW monsoons and westerlies . Its frequent lake level fluctuations arising from climatic and monsoonal changes have left a series of...Qinghai Lake is located in a hydrologically closed basin at the conjunction of SE and SW monsoons and westerlies . Its frequent lake level fluctuations arising from climatic and monsoonal changes have left a series of geological records since the last glaciation.The coarse sediments in Core QD1, the sporopollen assemblage representing steppe, the eolian paleo-sanddunes in the east and southeast banks and the fossil glacial topography all indicated frigid and arid climatic conditions and large scale shrinkage of the lake during the last glacial maximum.展开更多
The heavy floods in the Taihu Basin showed increasing trend in recent years. In this work, a typical area in the northern Taihu Basin was selected for flood risk analysis and potential flood losses assessment. Human a...The heavy floods in the Taihu Basin showed increasing trend in recent years. In this work, a typical area in the northern Taihu Basin was selected for flood risk analysis and potential flood losses assessment. Human activities have strong impact on the study area’s flood situation (as affected by the polders built, deforestation, population increase, urbanization, etc.), and have made water level higher, flood duration shorter, and flood peaks sharper. Five years of different flood return periods [(1970), 5 (1962), 10 (1987), 20 (1954), 50 (1991)] were used to calculate the potential flood risk area and its losses. The potential flood risk map, economic losses, and flood-impacted population were also calculated. The study’s main conclusions are: 1) Human activities have strongly changed the natural flood situation in the study area, increasing runoff and flooding; 2) The flood risk area is closely related with the precipitation center; 3) Polder construction has successfully protected land from flood, shortened the flood duration, and elevated water level in rivers outside the polders; 4) Economic and social development have caused flood losses to increase in recent years.展开更多
The Taihu Lake region in southern Jiangsu is one of the regions with flourishing economy and the highest level of urbanization due to favourable natural conditions and socio-economic foundation. However, there emerge ...The Taihu Lake region in southern Jiangsu is one of the regions with flourishing economy and the highest level of urbanization due to favourable natural conditions and socio-economic foundation. However, there emerge a seriers of urban ecological problems on continuous stretch of cities and towns, a vague division of urban functions, ground subsidence, serious pollution of atmosphere and waters arising from dense population, irrational distribution of industry, backwardeness of municipal engineering facilities, and inexperienced scientific management of water resources. In order to improve the urban eco-environment in this lake region, we should work out an overall regional eco梕nvironmental programme, perfect the urban economic set-up from the reqirements of urban material circulations and energy exchanges, and finally put into practice the urban functional regionalism, so that the Taihu Lake region in southern Jiangsu has not only a higher economic benefit, but also a beautiful and comfortable展开更多
An 82 cm core was collected from Qinghai Lake in the Qinghai- Xizang Plateau , China and sectioned in intervals of 1 cm for analysis of pigments (i.e. chlorophyll derivatives , carotenoids , myxoxanthophyll .oscillaxa...An 82 cm core was collected from Qinghai Lake in the Qinghai- Xizang Plateau , China and sectioned in intervals of 1 cm for analysis of pigments (i.e. chlorophyll derivatives , carotenoids , myxoxanthophyll .oscillaxanthin) and 210Pb .210Pb dating was used to establish the chronological sequence . The concentrations of myxoxanthophyll and oscillaxanthin from the cyanophytes increase with temperature. There are four peak values at 0-14 cm ( present-1891a), 25cm (1786a), 45cm (1581a) . 60cm (1416a) representing four warm and low water level periods during the past 700 years. This was confirmed by the high concentration of carbonate and 13C in these stages. In these 700 years , there were also 4 periods of cold wet climate and high water level as indicated by the tree ring index and high value of native chlorophyll and high , variable CD/TC ratios .展开更多
Lacustrine sediments, especially those of the closed lakes in semi-arid and arid areas, preserve abundant information and hence the lakes serve as an indicator of climatic and environmental changes, characterized by i...Lacustrine sediments, especially those of the closed lakes in semi-arid and arid areas, preserve abundant information and hence the lakes serve as an indicator of climatic and environmental changes, characterized by its continuity, sensitivity and high resolution. Now the studies on lake environmental changes on different time scales have become an important basis for establishing global climatic model. In order to study the characteristics of展开更多
Data from various sources including the ice core, inland lakes , paleosols in loess and eolian sands, sea level fluctuations, paleozoological, archeological evidences especially palynology and bontanical studies of Ch...Data from various sources including the ice core, inland lakes , paleosols in loess and eolian sands, sea level fluctuations, paleozoological, archeological evidences especially palynology and bontanical studies of China are reviewed . Holocene Megathermal mainly appeared during 8. 5-3 ka BP and lasted for 5. 5 ka. There were several strong climatic fluctuations and cooling events during this period, e. g. it was an unstable temperature fluctuation phase during 8. 5-7. 2 ka BP and was accompanied with the increase of the precipitation as well as the northward and westward migration of the vegetation zone ; the rapid development of Neolithic Culture happened in this phase. It was a stable warm and wet phase from 7. 2 to 6 ka BP, i. e. Megathermal Maximum, when monsoon was rainfall almost throughout China, plants were unprecedentedly flourished, and the Yangshao Culture reached its climax. It is characterized by strong climatic fluctuation and adverse environment during 6-5 ka BP and the impact of展开更多
Based on data from palynology, paleosols, paleolimnology, ice core, archeology, sea levels, etc. , we reconstructed climates and environments of the Holocene Megathermal maximum (7. 2-6. 0 ka B. P. ), particularly veg...Based on data from palynology, paleosols, paleolimnology, ice core, archeology, sea levels, etc. , we reconstructed climates and environments of the Holocene Megathermal maximum (7. 2-6. 0 ka B. P. ), particularly vegetation zones, temperatures, precipitation and sea-level fluctuations. Annual mean temperature during that period was estimated at 1 ℃ higher than today for South China, 2 ℃ higher for the Changjiang River Valley, about 3℃ higher for North China, Northeast China and Northwest China and up to 4 - 5 ℃ higher for southern Qinghai-Xizang Plateau. Relative winter temperatures increased much more than average annual temperatures. The centennial-scale warming was accompanied by the expansion of summer monsoon and recession of winter cold currents as well as northward and westward shift of vegetation zones. Higher lake levels registered in all inland lakes of Inner Mongolia, Xinjiang, Qinghai and Xizang indicated that precipitation increased to a certain extent. The Holocene highest sea level展开更多
A time-dependent linear model on the equatorial beta plane is developed in this paper.Its verticalstructure consists of two active layers with equal density and temperature above the thermocline and aquasi-stationary ...A time-dependent linear model on the equatorial beta plane is developed in this paper.Its verticalstructure consists of two active layers with equal density and temperature above the thermocline and aquasi-stationary layer with constant density below the thermocline.The results of nurnericat experiments show that the direct influence of heat on the equatorial ocean ismuch smaller than that of wind stress.Nevertheless,through the tropical ocean-atmosphere interaction,the change of wind stress resulting from the thermal forcing may set a determinant effect on the equilibriumand anomalous development of the ocean-almosphere circulation.展开更多
The concentrations of major elements and some trace elements were determined at 8 core locations in Taihu Lake. The chemical composition of the cores was related to the sediment particle size-chronology and location o...The concentrations of major elements and some trace elements were determined at 8 core locations in Taihu Lake. The chemical composition of the cores was related to the sediment particle size-chronology and location of sampling site.Concentrations of Al, Mg, K, Ca and Na, the major mineral species in the sediments, were generally uniform, with only slight fluctuation influenced by water waves and current. Surface enrichment of Cu, Zn, and Ni at some locations was observed to be greater than that of the sediments accumulated 100 years ago. The enrichment of these elements is attributed to anthropogenic input in recent years. Concentration profiles for Mn and Fe are related to the migration of these elements in the pore water.展开更多
The work presented previously by the authors(Cai and Liou,1982)has been extended in this paper.By making use of our improved model the calculations on scattering phase matrices of hexagonal prismice crystals(HPIC)have...The work presented previously by the authors(Cai and Liou,1982)has been extended in this paper.By making use of our improved model the calculations on scattering phase matrices of hexagonal prismice crystals(HPIC)have been conducted for monodisperse and polydisperse systems.Compared with themodel of Cai and Liou,the required computational quantity is decreased by about two orders of magni-tude and the errors of results are less for the new model.Meanwhile,the scattering phase matrices of triangularpyramid ice crystals(TPIC)are also computed in the paper,and the comparison between the scatterings of thetwo forms of ice crystals is performed.展开更多
Younger Dryas has been highlighted by paleoclimatologists in recent years becauseof the abrupt change of temperature and CO<sub>2</sub> concentration within a short timeof several centuries or even less. A...Younger Dryas has been highlighted by paleoclimatologists in recent years becauseof the abrupt change of temperature and CO<sub>2</sub> concentration within a short timeof several centuries or even less. At present, there exist virtually two viewpointsabout the event: one is that Younger Dryas only affects Circum-North Atlanticregion. The influx of the floating iceberg and the melt water from Arctic area to theNorth Atlantic Ocean due to the global warming in the Late Glacial suppressed展开更多
Core TMb is located about 3 km south of Maji Hill in Taihu Lake (Figs. 1 and 2),one of the five greatest freshwater lakes of China. The core is 1.15 m long, composed of light gray and black silty clay and of a Holocen...Core TMb is located about 3 km south of Maji Hill in Taihu Lake (Figs. 1 and 2),one of the five greatest freshwater lakes of China. The core is 1.15 m long, composed of light gray and black silty clay and of a Holocene age. 29 taxa of diatoms (Table, 1 Fig. 3) are recognized from 0.90—1.15 m depth sediments, 23 of which are marine taxa, 4 are ma-展开更多
文摘The following six aspects in the utilization of lake resources and progress of limnological research in China are described : 1 . Expeditions for comprehensive investigation of lakes ; 2 . Physical limnology; 3 . Lacustrine sedimentology and paleolimnology ; 4 . Hydrobiology and ecology ; 5 . Hydrochemistry and environmental protection; 6 . Development and utilization of lake resources.
文摘The rapid shrinkage of the surface area reflects the long-term deficit water budget of Qinghai Lake. Study of the yearly hydrology and meteorology in the lake catchment basin and the hydrologic factors as well as water budget led to the conclusion that evaporation exceeding the water input resulted in the drop of lake level, thai the obvious decrease of runoff to the lake and precipitation on the catchment accelerated the falling of lake level before 1987. and that increase of about 6.7% in rainfall on the whole basin will balance the lake’s water budget.
文摘Qinghai Lake is located in a hydrologically closed basin at the conjunction of SE and SW monsoons and westerlies . Its frequent lake level fluctuations arising from climatic and monsoonal changes have left a series of geological records since the last glaciation.The coarse sediments in Core QD1, the sporopollen assemblage representing steppe, the eolian paleo-sanddunes in the east and southeast banks and the fossil glacial topography all indicated frigid and arid climatic conditions and large scale shrinkage of the lake during the last glacial maximum.
文摘The heavy floods in the Taihu Basin showed increasing trend in recent years. In this work, a typical area in the northern Taihu Basin was selected for flood risk analysis and potential flood losses assessment. Human activities have strong impact on the study area’s flood situation (as affected by the polders built, deforestation, population increase, urbanization, etc.), and have made water level higher, flood duration shorter, and flood peaks sharper. Five years of different flood return periods [(1970), 5 (1962), 10 (1987), 20 (1954), 50 (1991)] were used to calculate the potential flood risk area and its losses. The potential flood risk map, economic losses, and flood-impacted population were also calculated. The study’s main conclusions are: 1) Human activities have strongly changed the natural flood situation in the study area, increasing runoff and flooding; 2) The flood risk area is closely related with the precipitation center; 3) Polder construction has successfully protected land from flood, shortened the flood duration, and elevated water level in rivers outside the polders; 4) Economic and social development have caused flood losses to increase in recent years.
文摘The Taihu Lake region in southern Jiangsu is one of the regions with flourishing economy and the highest level of urbanization due to favourable natural conditions and socio-economic foundation. However, there emerge a seriers of urban ecological problems on continuous stretch of cities and towns, a vague division of urban functions, ground subsidence, serious pollution of atmosphere and waters arising from dense population, irrational distribution of industry, backwardeness of municipal engineering facilities, and inexperienced scientific management of water resources. In order to improve the urban eco-environment in this lake region, we should work out an overall regional eco梕nvironmental programme, perfect the urban economic set-up from the reqirements of urban material circulations and energy exchanges, and finally put into practice the urban functional regionalism, so that the Taihu Lake region in southern Jiangsu has not only a higher economic benefit, but also a beautiful and comfortable
基金The project was supported by the Loess and Quaternary Research Lab,Academia Sinica
文摘An 82 cm core was collected from Qinghai Lake in the Qinghai- Xizang Plateau , China and sectioned in intervals of 1 cm for analysis of pigments (i.e. chlorophyll derivatives , carotenoids , myxoxanthophyll .oscillaxanthin) and 210Pb .210Pb dating was used to establish the chronological sequence . The concentrations of myxoxanthophyll and oscillaxanthin from the cyanophytes increase with temperature. There are four peak values at 0-14 cm ( present-1891a), 25cm (1786a), 45cm (1581a) . 60cm (1416a) representing four warm and low water level periods during the past 700 years. This was confirmed by the high concentration of carbonate and 13C in these stages. In these 700 years , there were also 4 periods of cold wet climate and high water level as indicated by the tree ring index and high value of native chlorophyll and high , variable CD/TC ratios .
基金Project partly supported by the National Natural Science Foundation of China.
文摘Lacustrine sediments, especially those of the closed lakes in semi-arid and arid areas, preserve abundant information and hence the lakes serve as an indicator of climatic and environmental changes, characterized by its continuity, sensitivity and high resolution. Now the studies on lake environmental changes on different time scales have become an important basis for establishing global climatic model. In order to study the characteristics of
基金Project supported by the National Natural Science Foundation of China and the Chinese Academy of Sciences.
文摘Data from various sources including the ice core, inland lakes , paleosols in loess and eolian sands, sea level fluctuations, paleozoological, archeological evidences especially palynology and bontanical studies of China are reviewed . Holocene Megathermal mainly appeared during 8. 5-3 ka BP and lasted for 5. 5 ka. There were several strong climatic fluctuations and cooling events during this period, e. g. it was an unstable temperature fluctuation phase during 8. 5-7. 2 ka BP and was accompanied with the increase of the precipitation as well as the northward and westward migration of the vegetation zone ; the rapid development of Neolithic Culture happened in this phase. It was a stable warm and wet phase from 7. 2 to 6 ka BP, i. e. Megathermal Maximum, when monsoon was rainfall almost throughout China, plants were unprecedentedly flourished, and the Yangshao Culture reached its climax. It is characterized by strong climatic fluctuation and adverse environment during 6-5 ka BP and the impact of
文摘Based on data from palynology, paleosols, paleolimnology, ice core, archeology, sea levels, etc. , we reconstructed climates and environments of the Holocene Megathermal maximum (7. 2-6. 0 ka B. P. ), particularly vegetation zones, temperatures, precipitation and sea-level fluctuations. Annual mean temperature during that period was estimated at 1 ℃ higher than today for South China, 2 ℃ higher for the Changjiang River Valley, about 3℃ higher for North China, Northeast China and Northwest China and up to 4 - 5 ℃ higher for southern Qinghai-Xizang Plateau. Relative winter temperatures increased much more than average annual temperatures. The centennial-scale warming was accompanied by the expansion of summer monsoon and recession of winter cold currents as well as northward and westward shift of vegetation zones. Higher lake levels registered in all inland lakes of Inner Mongolia, Xinjiang, Qinghai and Xizang indicated that precipitation increased to a certain extent. The Holocene highest sea level
基金This paper was completed in the Institute of Atmospheric Physics,Academia Sinica,Beijing
文摘A time-dependent linear model on the equatorial beta plane is developed in this paper.Its verticalstructure consists of two active layers with equal density and temperature above the thermocline and aquasi-stationary layer with constant density below the thermocline.The results of nurnericat experiments show that the direct influence of heat on the equatorial ocean ismuch smaller than that of wind stress.Nevertheless,through the tropical ocean-atmosphere interaction,the change of wind stress resulting from the thermal forcing may set a determinant effect on the equilibriumand anomalous development of the ocean-almosphere circulation.
文摘The concentrations of major elements and some trace elements were determined at 8 core locations in Taihu Lake. The chemical composition of the cores was related to the sediment particle size-chronology and location of sampling site.Concentrations of Al, Mg, K, Ca and Na, the major mineral species in the sediments, were generally uniform, with only slight fluctuation influenced by water waves and current. Surface enrichment of Cu, Zn, and Ni at some locations was observed to be greater than that of the sediments accumulated 100 years ago. The enrichment of these elements is attributed to anthropogenic input in recent years. Concentration profiles for Mn and Fe are related to the migration of these elements in the pore water.
文摘The work presented previously by the authors(Cai and Liou,1982)has been extended in this paper.By making use of our improved model the calculations on scattering phase matrices of hexagonal prismice crystals(HPIC)have been conducted for monodisperse and polydisperse systems.Compared with themodel of Cai and Liou,the required computational quantity is decreased by about two orders of magni-tude and the errors of results are less for the new model.Meanwhile,the scattering phase matrices of triangularpyramid ice crystals(TPIC)are also computed in the paper,and the comparison between the scatterings of thetwo forms of ice crystals is performed.
文摘Younger Dryas has been highlighted by paleoclimatologists in recent years becauseof the abrupt change of temperature and CO<sub>2</sub> concentration within a short timeof several centuries or even less. At present, there exist virtually two viewpointsabout the event: one is that Younger Dryas only affects Circum-North Atlanticregion. The influx of the floating iceberg and the melt water from Arctic area to theNorth Atlantic Ocean due to the global warming in the Late Glacial suppressed
基金Project supported by the National Natural Science Foundation of China and Lake Sediment & Environment Lab
文摘Core TMb is located about 3 km south of Maji Hill in Taihu Lake (Figs. 1 and 2),one of the five greatest freshwater lakes of China. The core is 1.15 m long, composed of light gray and black silty clay and of a Holocene age. 29 taxa of diatoms (Table, 1 Fig. 3) are recognized from 0.90—1.15 m depth sediments, 23 of which are marine taxa, 4 are ma-
