1999年 第9卷 第1期
1999, 9(1): 1-11.
摘要:
In the summer of 1998, a rarely severe flooding disaster occurred in the whole basin of the Changjiang(Yangtze) River, which caused enormous losses. By 22nd of August, 29 provinces, autonomous regions and municipalitieswere involved, 21. 2 million ha of land were inundated, 223 million people were affected, 3004 people were killed and4. 97 million buildings were collapsed. The estimated direct loss of the country accounted to 166. 6 billion yuan (RMB).The main reason of the disaster is the unusual climate but the unreasonable land utilization the aggravated the disaster.This paper consists of two parts. One part analysed the unreasonable land utilization, including the neglect of forest landprotection, which caused the forest land area to decrease by 440 thousand ha in the whole country every year, the enclosing of lakes for cultivation, which decreased the area of lakes located along the banks of the Changjiang River from 17200km2 at the beginning of the founding of the People's Republic of China to 6531km2 in 1983, the changing of functions oflakes, which reduced the volume of storage exceedingly, for example, only 5 spots of lakes were used for storing water inWuhan City, and the slow progress of the construction of flood diversion and storage area, which would cause huge lossesonce flood was diverted. The other part explored the strategy of land utilization on the supplying of land for flood controlprojects, such as embankment, drainage installation, flood diversion and storage area, and on tapping the potentialsthrough narrowing and amalgamgting the range of rural residential quarters and small towns, reclaiming reserved resources, transforming middle and low productive fields, attaching importance to land arrangement and recultivation, and adjusting contracted fields partially, to ensure the sustainable and stable growth of the region.
In the summer of 1998, a rarely severe flooding disaster occurred in the whole basin of the Changjiang(Yangtze) River, which caused enormous losses. By 22nd of August, 29 provinces, autonomous regions and municipalitieswere involved, 21. 2 million ha of land were inundated, 223 million people were affected, 3004 people were killed and4. 97 million buildings were collapsed. The estimated direct loss of the country accounted to 166. 6 billion yuan (RMB).The main reason of the disaster is the unusual climate but the unreasonable land utilization the aggravated the disaster.This paper consists of two parts. One part analysed the unreasonable land utilization, including the neglect of forest landprotection, which caused the forest land area to decrease by 440 thousand ha in the whole country every year, the enclosing of lakes for cultivation, which decreased the area of lakes located along the banks of the Changjiang River from 17200km2 at the beginning of the founding of the People's Republic of China to 6531km2 in 1983, the changing of functions oflakes, which reduced the volume of storage exceedingly, for example, only 5 spots of lakes were used for storing water inWuhan City, and the slow progress of the construction of flood diversion and storage area, which would cause huge lossesonce flood was diverted. The other part explored the strategy of land utilization on the supplying of land for flood controlprojects, such as embankment, drainage installation, flood diversion and storage area, and on tapping the potentialsthrough narrowing and amalgamgting the range of rural residential quarters and small towns, reclaiming reserved resources, transforming middle and low productive fields, attaching importance to land arrangement and recultivation, and adjusting contracted fields partially, to ensure the sustainable and stable growth of the region.
1999, 9(1): 12-19.
摘要:
In China, systematic studies on economic base of a single city are very weak. Based on the 1990 census andrelevant statistics during 1990 - 1994, a comparative study is conducted on Beijing, Shanghai and Tianjin. The majorconclusions are as follows: (1) Beijing is not only the national political and cultural center, but also the national economiccenter, viz the commercial service center and the low water-consuming, light polluting, external economy-typed andknowledge-intensive manufacturing industrial center, which is appropriate for Beijing's comparative advantage. (2) Thehigh water-consuming, heavy polluting and regional market-oriented industry is overdeveloped as far as Beijing's scarcewater and other natural resources are concerned. (3) Beijing's industrial base is smaller, more regional market-based, andthe service base is more diverse, larger and more national market-based than Shanghai's and Tianjin's. (4) With the development of socialist market economy and implemenl of sustainable development strategy, the external economy-typedand knowledge-intensive manufacturing industry with lower input of water and less environmental pollution, and information-intensive service industries will centralize further, and the industry with higher input of water and/or severe environmental pollution will decentralize.
In China, systematic studies on economic base of a single city are very weak. Based on the 1990 census andrelevant statistics during 1990 - 1994, a comparative study is conducted on Beijing, Shanghai and Tianjin. The majorconclusions are as follows: (1) Beijing is not only the national political and cultural center, but also the national economiccenter, viz the commercial service center and the low water-consuming, light polluting, external economy-typed andknowledge-intensive manufacturing industrial center, which is appropriate for Beijing's comparative advantage. (2) Thehigh water-consuming, heavy polluting and regional market-oriented industry is overdeveloped as far as Beijing's scarcewater and other natural resources are concerned. (3) Beijing's industrial base is smaller, more regional market-based, andthe service base is more diverse, larger and more national market-based than Shanghai's and Tianjin's. (4) With the development of socialist market economy and implemenl of sustainable development strategy, the external economy-typedand knowledge-intensive manufacturing industry with lower input of water and less environmental pollution, and information-intensive service industries will centralize further, and the industry with higher input of water and/or severe environmental pollution will decentralize.
1999, 9(1): 20-25.
摘要:
Based on development level of regional societye and economy, the paper attempts oto analyze the present situation, types and change of regional environment in China through the definition of four conceptions environmental pollution index (EPI), social and economic comprehensive index (SECI), -environmental comprehensive index (ECI) and social, economic and environmental environmental index (SEECI) and some mathematical calculation, and draws someconclusions to be worth referring: 1). There exists close relation between economic development and environmental situation. With high-speed development of economy, the discharge of the three wastes in China has been increasing, but itsenvironmental social and economic benefit has also been improved the same the time. 2) In the course of economic development, regional environment situation in China has continuously been changing, and there exists the difference of environmental quality between provinces, which is bigger than that of economic development level between there. 3) Except veryfew provinces, regional EPI in China has risen in varying degrees since the 1980s, which shows that the task for China toprevent environment from polluting is still arduous.
Based on development level of regional societye and economy, the paper attempts oto analyze the present situation, types and change of regional environment in China through the definition of four conceptions environmental pollution index (EPI), social and economic comprehensive index (SECI), -environmental comprehensive index (ECI) and social, economic and environmental environmental index (SEECI) and some mathematical calculation, and draws someconclusions to be worth referring: 1). There exists close relation between economic development and environmental situation. With high-speed development of economy, the discharge of the three wastes in China has been increasing, but itsenvironmental social and economic benefit has also been improved the same the time. 2) In the course of economic development, regional environment situation in China has continuously been changing, and there exists the difference of environmental quality between provinces, which is bigger than that of economic development level between there. 3) Except veryfew provinces, regional EPI in China has risen in varying degrees since the 1980s, which shows that the task for China toprevent environment from polluting is still arduous.
1999, 9(1): 26-32.
摘要:
Produced in China's physical environment, traditional Chinese residential architecture is restrained by socialfactors and adapts itself to the natural economy. Physical geographical environment does not solely shape architecturalstyles. However, in the self-sufficient economy era, it deeply influenced the culture of traditional Chinese residential architecture. This thesis discuss ragional influence of climate on the spatial patterns and styles of residential architecture; italso analyzes the influence of landforms and water systems on architectural landscapes and local housing selections. Geologyand botany play another important role in forming local features and improving microenvironment around builidings. Withthe comprehensive effects of all elements that take climate as the key one, architectural styles differ evidently in various regions. On the above basis, analysis is made to find the view of nature of traditional residential architecture culture with theconnotative views of utility, aesthetic perception and ecology. By analyzing the effects of physical geographical factors onChina's residential architecture and exploring the natural view in its cultural and spiritual aspects, some enlightenmentmay be gained to protect protecal environment and realize harmony among man, architecture and environment, thus developing the culture of modern residential architecture with local flavor and characteristics.
Produced in China's physical environment, traditional Chinese residential architecture is restrained by socialfactors and adapts itself to the natural economy. Physical geographical environment does not solely shape architecturalstyles. However, in the self-sufficient economy era, it deeply influenced the culture of traditional Chinese residential architecture. This thesis discuss ragional influence of climate on the spatial patterns and styles of residential architecture; italso analyzes the influence of landforms and water systems on architectural landscapes and local housing selections. Geologyand botany play another important role in forming local features and improving microenvironment around builidings. Withthe comprehensive effects of all elements that take climate as the key one, architectural styles differ evidently in various regions. On the above basis, analysis is made to find the view of nature of traditional residential architecture culture with theconnotative views of utility, aesthetic perception and ecology. By analyzing the effects of physical geographical factors onChina's residential architecture and exploring the natural view in its cultural and spiritual aspects, some enlightenmentmay be gained to protect protecal environment and realize harmony among man, architecture and environment, thus developing the culture of modern residential architecture with local flavor and characteristics.
1999, 9(1): 33-39.
摘要:
The discussion on sedimentary macro-structures and their forming mechanics of debris flow is based on thedata of present processes and ancient deposits of Dongchuan in Yunnan Province, Wudu in Gansu Province and Fuxin inLiaoning Province. Non-cohesive debris flow, which is 1.3-1.7t/m3 in density, follows hydraulic fluid and flow model. In the hydraulic fluid of flood, electrolytic water combines clay into pulp to transport solid debris. The sedimentary structures show fluid processes as stone-line structure, imbricated structure and stone supporting-sustructure. A part of non-cohesive debris flow with a density of 1.7-1.9t/m3 follows granular model. Debris is in the action of friction, collision and dispersion which forces as debris moving upward to form reverse graded load. The sedimentary structures of granular flow show reverse graded bedding, reverse-normal graded bedding, imbricated verticalstructure and circling linear structure.Cohesive debris flow, which is 1.9-2.3t/m3 in density, follows structural two phase flow (viscoplastic) model. The sedimentary structures of cohesive debris flow show reverse graded-chaotic structure,bottom mud-chaotic structure and outwedging structure.
The discussion on sedimentary macro-structures and their forming mechanics of debris flow is based on thedata of present processes and ancient deposits of Dongchuan in Yunnan Province, Wudu in Gansu Province and Fuxin inLiaoning Province. Non-cohesive debris flow, which is 1.3-1.7t/m3 in density, follows hydraulic fluid and flow model. In the hydraulic fluid of flood, electrolytic water combines clay into pulp to transport solid debris. The sedimentary structures show fluid processes as stone-line structure, imbricated structure and stone supporting-sustructure. A part of non-cohesive debris flow with a density of 1.7-1.9t/m3 follows granular model. Debris is in the action of friction, collision and dispersion which forces as debris moving upward to form reverse graded load. The sedimentary structures of granular flow show reverse graded bedding, reverse-normal graded bedding, imbricated verticalstructure and circling linear structure.Cohesive debris flow, which is 1.9-2.3t/m3 in density, follows structural two phase flow (viscoplastic) model. The sedimentary structures of cohesive debris flow show reverse graded-chaotic structure,bottom mud-chaotic structure and outwedging structure.
1999, 9(1): 40-48.
摘要:
This paper presents the applications of Landsat Thematic Mapper (TM) data and Advanced Very High Resolution Radiometer (AVHRR) time series data for winter wheat production estimation in North China Plain. The keytechniques are described systematically about winter wheat yield estimation system, including automatically extractingwheat area, simulating and monitoring wheat growth situation, building wheat unit yield model of large area and forecasting wheat production. Pattern recognition technique was applied to extract sown area using TM data. Temporal NDVI(Normal Division Vegetation Index) profiles were produced from 8-12 times AVHRR data during wheat growth dynamically. A remote sensing yield model for large area was developed based on greenness accumulation, temperature andgreenness change rate. On the basis of the solution of key problems, an operational system for winter wheat yield estimation in North China Plain using remotely sensed data was established and has operated since 1993, which consists of 4 subsystems, namely databases management, image processing, models bank management and production prediction system.The accuracy of wheat production prediction exceeded 96 per cent compared with on the spot measurement.
This paper presents the applications of Landsat Thematic Mapper (TM) data and Advanced Very High Resolution Radiometer (AVHRR) time series data for winter wheat production estimation in North China Plain. The keytechniques are described systematically about winter wheat yield estimation system, including automatically extractingwheat area, simulating and monitoring wheat growth situation, building wheat unit yield model of large area and forecasting wheat production. Pattern recognition technique was applied to extract sown area using TM data. Temporal NDVI(Normal Division Vegetation Index) profiles were produced from 8-12 times AVHRR data during wheat growth dynamically. A remote sensing yield model for large area was developed based on greenness accumulation, temperature andgreenness change rate. On the basis of the solution of key problems, an operational system for winter wheat yield estimation in North China Plain using remotely sensed data was established and has operated since 1993, which consists of 4 subsystems, namely databases management, image processing, models bank management and production prediction system.The accuracy of wheat production prediction exceeded 96 per cent compared with on the spot measurement.
1999, 9(1): 49-56.
摘要:
NOAA-AVHRR data have been more and more used by scientists because of its short temporal resolution,large scope, inexpensive cost and broad wave bands. On macro and middle scale of vegetation remote sensing, NOAAAVHRR possesses an advantage when compared with other satellites. However, because NOAA-AVHRR also problem of low resolution, data distortion and geometrical distortion, in the area of application of NOAA-AVHRR in largescale vegetation-mapping, the accuracy of vegetation classification should be improved. This paper discuss the feasibilityof integrating the geographic data in GIS(Geographical Information System) and remotely sensed data in GIS. Under theenvironment of GIS, temperature, precipitation and elevation, which serve as main factors affecting vegetation growth,were processed by a mathematical model and qualified into geographic image under a certain grid system. The geographicimage were overlaid to the NOAA-AVHRR data which had been compressed and processed. In order to evaluate the usefulness of geographic data for vegetation classification, the area under study was digitally classified by two groups of interpreter: the proposed methodology using maximum likelihood classification assisted by the geographic database and a conventional maximum likelihood classification only. Both result were compared using Kappa statistics. The indices to both theproposed and the conventional digital classification methodology were 0.668(very good) and 0.563(good), respetively.The geographic database rendered an improvement over the conventional digital classification. Furthermore, in this study,some problems related to multi-sources data integration are also discussed.
NOAA-AVHRR data have been more and more used by scientists because of its short temporal resolution,large scope, inexpensive cost and broad wave bands. On macro and middle scale of vegetation remote sensing, NOAAAVHRR possesses an advantage when compared with other satellites. However, because NOAA-AVHRR also problem of low resolution, data distortion and geometrical distortion, in the area of application of NOAA-AVHRR in largescale vegetation-mapping, the accuracy of vegetation classification should be improved. This paper discuss the feasibilityof integrating the geographic data in GIS(Geographical Information System) and remotely sensed data in GIS. Under theenvironment of GIS, temperature, precipitation and elevation, which serve as main factors affecting vegetation growth,were processed by a mathematical model and qualified into geographic image under a certain grid system. The geographicimage were overlaid to the NOAA-AVHRR data which had been compressed and processed. In order to evaluate the usefulness of geographic data for vegetation classification, the area under study was digitally classified by two groups of interpreter: the proposed methodology using maximum likelihood classification assisted by the geographic database and a conventional maximum likelihood classification only. Both result were compared using Kappa statistics. The indices to both theproposed and the conventional digital classification methodology were 0.668(very good) and 0.563(good), respetively.The geographic database rendered an improvement over the conventional digital classification. Furthermore, in this study,some problems related to multi-sources data integration are also discussed.
1999, 9(1): 57-62.
摘要:
Using the precipitation data in recent 40 years of 48 meteorological stations in Taklimakan area and neighboring areas, this paper analyzes the stage and periodicity of the wet-dry changes in a year and four seasons. The paper also compares the correlativity of precipitation between Taklimakan area and around Mountains, and obtained some statisticconclusions as follows. (1) The precipitation changes of a year and four seasons in Taklimakan area have different wet-dryperiods and change periodicities. (2) Summer precipitation has well directive sense to annual precipitation in Taklimakanarea with a correlation coefficient 0. 901, and the negative correlation between precipitation and temperature in summer isvery remarkable. (3) There is definite correlation between annual precipitation in Taklimakan area and position of polarvortex. When longitude of polar vortex is partial west in February and its latitude is partial north in September of the lastyear, annual precipitation is above its mean in the area. In addition, it is beneficial to obtain more summer precipitation inthe area when position of polar vortex is partial west in February.
Using the precipitation data in recent 40 years of 48 meteorological stations in Taklimakan area and neighboring areas, this paper analyzes the stage and periodicity of the wet-dry changes in a year and four seasons. The paper also compares the correlativity of precipitation between Taklimakan area and around Mountains, and obtained some statisticconclusions as follows. (1) The precipitation changes of a year and four seasons in Taklimakan area have different wet-dryperiods and change periodicities. (2) Summer precipitation has well directive sense to annual precipitation in Taklimakanarea with a correlation coefficient 0. 901, and the negative correlation between precipitation and temperature in summer isvery remarkable. (3) There is definite correlation between annual precipitation in Taklimakan area and position of polarvortex. When longitude of polar vortex is partial west in February and its latitude is partial north in September of the lastyear, annual precipitation is above its mean in the area. In addition, it is beneficial to obtain more summer precipitation inthe area when position of polar vortex is partial west in February.
1999, 9(1): 63-69.
摘要:
Owing to intensive human activities and the floods of the Huaihe River in historic peiod, the contiguous region of Jiangsu, Shandong, Henan and Anhui provinces is suffering from a variety of environmental problems and naturaldisasters, of which water pollution and drought-flood disasters are most observable. Considering the special location andenvironmental status of the contiguous region, advices are proposed in the paper: perfecting trans-regional managementssystem of water environment incorporating basin management agencies in local government activities; strengthening cooperation of two agencies: water conservancy agency and environment protection agency; enhancing integrated control ofwater pollution and flood-drought disasters; taking the interests of the whole river into acount and paying attention to bothstorage and drainage; broadening sources of water supply and inceasing water delivery; controlling pollutant discharge,developing water saving production system.
Owing to intensive human activities and the floods of the Huaihe River in historic peiod, the contiguous region of Jiangsu, Shandong, Henan and Anhui provinces is suffering from a variety of environmental problems and naturaldisasters, of which water pollution and drought-flood disasters are most observable. Considering the special location andenvironmental status of the contiguous region, advices are proposed in the paper: perfecting trans-regional managementssystem of water environment incorporating basin management agencies in local government activities; strengthening cooperation of two agencies: water conservancy agency and environment protection agency; enhancing integrated control ofwater pollution and flood-drought disasters; taking the interests of the whole river into acount and paying attention to bothstorage and drainage; broadening sources of water supply and inceasing water delivery; controlling pollutant discharge,developing water saving production system.
1999, 9(1): 70-77.
摘要:
The paper studies the methodologies of the cargo flow study and projections in Tumen River Economic Development Area(TREDA) that some governments and international scholars used. The authors consider that, in order topromote investment, facilitation of cross-border trade and infrastructure in the region, the basic methodology should bebased on the regional economic growth of pertinent Northeast Asian countries and regions to make projections of the situations of regional cargo flows, and then analyzing the cargo flow trend. Based on the above, the authors utilize the routescomparing model and gravity model to forecast the cargo flows through the ports and related routes in TREDA (2000 -2020). The authors also inquire into the main obstacles which affect the cargo flows of the region, analyze the influenceson cargo flows if the obstacles change with sensitivity analyses and try to find the way to sole the obstacles.
The paper studies the methodologies of the cargo flow study and projections in Tumen River Economic Development Area(TREDA) that some governments and international scholars used. The authors consider that, in order topromote investment, facilitation of cross-border trade and infrastructure in the region, the basic methodology should bebased on the regional economic growth of pertinent Northeast Asian countries and regions to make projections of the situations of regional cargo flows, and then analyzing the cargo flow trend. Based on the above, the authors utilize the routescomparing model and gravity model to forecast the cargo flows through the ports and related routes in TREDA (2000 -2020). The authors also inquire into the main obstacles which affect the cargo flows of the region, analyze the influenceson cargo flows if the obstacles change with sensitivity analyses and try to find the way to sole the obstacles.
1999, 9(1): 78-82.
摘要:
Located in the central Asia, ancient Loullan Town was a place of strategic importance to the ancient SilkRoad. According to the historical records, it was flourishing during the period from the second century B. C. to the thirdcentury A. D. However, it was disrecorded suddenly 1400 years ago. Until 1900 it was discovered by a Swedish exploration party. The ruins of Loulan is situated on the west bank of Lop Nur Lake and the delta of the Tarim River (40°29'55''N, 89°55'22"E), and occupies an area of 108240 m2. Two main tributaries of the Tarim River passed by its northernand southern sides respectively and converged into Lop Nur Lake about 100 km eastward. Human civilization of the Loulan Town had been developed in the Stone Age, which was revealed by a lot of stone implements found in the ration, andthe discovery of the corpse of "Loulan Beauty" proved the continuity of economic development. During several centuriesaround the Christian era, Loulan had become a place of strategic importance on the Silk Road because its superior geographical position and natural conditions. The decline of ancient Loulan Town was caused by natural change of the rivercourses and rapid environmental deterioration.
Located in the central Asia, ancient Loullan Town was a place of strategic importance to the ancient SilkRoad. According to the historical records, it was flourishing during the period from the second century B. C. to the thirdcentury A. D. However, it was disrecorded suddenly 1400 years ago. Until 1900 it was discovered by a Swedish exploration party. The ruins of Loulan is situated on the west bank of Lop Nur Lake and the delta of the Tarim River (40°29'55''N, 89°55'22"E), and occupies an area of 108240 m2. Two main tributaries of the Tarim River passed by its northernand southern sides respectively and converged into Lop Nur Lake about 100 km eastward. Human civilization of the Loulan Town had been developed in the Stone Age, which was revealed by a lot of stone implements found in the ration, andthe discovery of the corpse of "Loulan Beauty" proved the continuity of economic development. During several centuriesaround the Christian era, Loulan had become a place of strategic importance on the Silk Road because its superior geographical position and natural conditions. The decline of ancient Loulan Town was caused by natural change of the rivercourses and rapid environmental deterioration.
1999, 9(1): 83-86.
摘要:
High peat is a good message carrier of atmospheric geochemical environment.The distribution of heavy metals monitored in vertical vertion of high peat is the reflection of sequence atmospheric chemical composition. It can record and remain thenatural geochemical background of the atmosphere. The changes of heavy metal contets in sections of the Da Hinggan Mountainsmanifest that the influence of human human on atmosphere is continuously becoming heavier. Compared with other areas inEurasia, the atmospheric geochemical anomaly of this area is not obvious. By monitoring high peats in different geographic areas,the character of anthropologic geochemical anomaly in atmosphere could be ascertained.
High peat is a good message carrier of atmospheric geochemical environment.The distribution of heavy metals monitored in vertical vertion of high peat is the reflection of sequence atmospheric chemical composition. It can record and remain thenatural geochemical background of the atmosphere. The changes of heavy metal contets in sections of the Da Hinggan Mountainsmanifest that the influence of human human on atmosphere is continuously becoming heavier. Compared with other areas inEurasia, the atmospheric geochemical anomaly of this area is not obvious. By monitoring high peats in different geographic areas,the character of anthropologic geochemical anomaly in atmosphere could be ascertained.
1999, 9(1): 87-91.
摘要:
In this paper, the Holocene paleoenvironment change sequence in middle Inner Mongolia was primarily reconstructed on the basis of palynological analysis at the resolution of 70 years on a peat profile, which was located in thenorthern part of Tumd Plain with its oldest age of 9100 a. B. P. As the consequence indicated, the Holocene climatechange in the middle Inner Mongolia had undergone cool→temperate→ warm→ temperate→ cool series, and the historycould be divided into 5 epochs: 9100-7400 a B. P., with slightly arid and cold climate;7400-5000 a B. P., transitoryclimate with dynamic fluctuation, earlier period temperate and slightly arid, and later period temperate and slightly humid; 5000 - 4100 a B. P., with warm and humid climate; 4100-1350 a B. P., with transitory climate getting arid, asthe result of human being's growing influence; 1350 a B. P.-present, with temperate and slightly arid climate, understrong influence of human being. The warm period of Holocene occurred in 7400-4000 a B. P., while the optimal periodoccurred in 5000-4100 a B. P.
In this paper, the Holocene paleoenvironment change sequence in middle Inner Mongolia was primarily reconstructed on the basis of palynological analysis at the resolution of 70 years on a peat profile, which was located in thenorthern part of Tumd Plain with its oldest age of 9100 a. B. P. As the consequence indicated, the Holocene climatechange in the middle Inner Mongolia had undergone cool→temperate→ warm→ temperate→ cool series, and the historycould be divided into 5 epochs: 9100-7400 a B. P., with slightly arid and cold climate;7400-5000 a B. P., transitoryclimate with dynamic fluctuation, earlier period temperate and slightly arid, and later period temperate and slightly humid; 5000 - 4100 a B. P., with warm and humid climate; 4100-1350 a B. P., with transitory climate getting arid, asthe result of human being's growing influence; 1350 a B. P.-present, with temperate and slightly arid climate, understrong influence of human being. The warm period of Holocene occurred in 7400-4000 a B. P., while the optimal periodoccurred in 5000-4100 a B. P.
1999, 9(1): 92-95.
摘要:
The Qaidam Basin is one of the main areas where the desert of the Qinghai-Xizang Plateau is distributed.According to the envirotunment records and the age of stratigraphy in Xiaxitai section in southeast part of Qaidam Basin,this paper reached the following conclusions: the desert development, formation of the cold-dry climate, evolution of natural environment and their reverse changes occurred frequently since the late glacial. In eolian sand deposits, the YoungerDryas event clearly appeared, which manifesed a dry-cold climatic period. Now there are two different opinions about theclimatic effect of Younger Dryas. According to the predecessors'research and the field work of the authors, it is considered that the Younger Dryas event not only exists in different climatic zones of China, but the manifests the unitary dry-cold climatic effect.
The Qaidam Basin is one of the main areas where the desert of the Qinghai-Xizang Plateau is distributed.According to the envirotunment records and the age of stratigraphy in Xiaxitai section in southeast part of Qaidam Basin,this paper reached the following conclusions: the desert development, formation of the cold-dry climate, evolution of natural environment and their reverse changes occurred frequently since the late glacial. In eolian sand deposits, the YoungerDryas event clearly appeared, which manifesed a dry-cold climatic period. Now there are two different opinions about theclimatic effect of Younger Dryas. According to the predecessors'research and the field work of the authors, it is considered that the Younger Dryas event not only exists in different climatic zones of China, but the manifests the unitary dry-cold climatic effect.
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