A new scheme for climate regionalization in China was established based on the daily observations for 609 meteorological stations during the period 1971-2000.During regionalization,current basic theories,classification methodologies and criteria system were used,besides,five principles were taken into consideration,mainly included zonal and azonal integration,genetic unity and regional relative consistent climate integration,comprehensiveness and leading factors integration,bottom-up and top-down integration,spatial continuity and small patch omission.The new scheme consists of 12 temperature zones,24 moisture regions and 56 climatic sub-regions.
Based on Landsat TM(/MSS) images in 1976,1988 and 2006,glacier extents in the three periods in the Mt.Qomolangma National Nature Preserve(QNNP) have been automatically derived by object-oriented image interpretation method combined with expert knowledge rules and field surveys.Spatial-temporal distribution and changes of glaciers are analyzed with the aid of GIS,RS and Tupu method.Results show that(1) The glacial area at QNNP in 2006,located mainly in the southern high mountain region with elevations of 4700-6800 m,amounted to 2710.17±0.011 km2,about 7.41% of the whole study area;(2) During 1976-2006,glaciers tended to shrink significantly by 501.91±0.035 km2 in total,and glacial lakes expanded rapidly with an increase of 36.88±0.035 km2;the rate of glacier retreat is higher in sub-basins on the southern slope(16.79%) of Himalayas than those on the northern slope(14.40%);(3) Most glaciers retreated,mainly occurred at elevations of 4700-6400 m,and the estimated upper limit of retreated zone is between 6600 m and 6700 m;(4) The temperature rise along with precipitation decrease is considered to be the key factor of glacier retreat in the region.
The criteria for glacier lake inventory were set up and two phases of glacier lake inventories work of the Chinese Himalayas were carried out on the basis of the 278 topography maps(1970s-1980s),38 ASTER images(2004-2008,including 7 Land-sat Thematic Mapper images from 2004-2008 were used to fill the minor gaps between ASTER images),the DEMs and slope maps generated from the 278 topography maps and etc.in this paper.In comparison to the two phases of glacier lake inventories data,we found that the glacier lake variations are characterized by a general trend of "the decrease in the number of glacier lakes and the increase in area of glacier lakes"in the Chinese Himalayas during the past 30 years.Further analysis shows that,in recent 30 years,(1) the number of glacier lake decreased from 1750 to 1680(with a rate of 4%) whereas the area of glacier lake increased from 166.48 km2 to 215.28 km2(with a rate of 29%);(2) A total of 294 glacier lakes disappeared and 224 glacier lakes formed;(3) among the 6 types of glacier lakes,66% that disappeared were glacier lakes and 88% of newly formed glacier lakes were moraine-dammed ones;(4) the glacier lakes varied more significantly at the edge of survival glaciers due to the fact that the climate was warming and glaciers were retreating in the region of Chinese Himalayas.
Loess is widely distributed in Chinese Loess Plateau,and the aeolian sediments have been regarded as one of the most vigorous terrestrial records of paleoclimatic changes during the Quaternary.So far,a large number of investigations have been carried out on palaeoenvironmental changes.However,origination,transportation,and deposition of the eolian sediments,as well as the erosion after deposition,have not been well understood.In this study,we examine 84 individual representative loess-paleosol sections collected from our measurements and literatures,and estimate the total dust deposition amounts and average mass accumulation rates on the Loess Plateau of each glacial or interglacial period over the past 250 ka by remote sensing analysis and Kriging interpolation method.The results provide new evidence for the relation between regional dust deposition and orbit-scale climate changes:the dust accumulation rate is higher in the glacial periods than that in the interglacial periods.Furthermore,based on the modern observation,we estimate average surface erosion rates on the Loess Plateau in each glacial or interglacial period over the past 250 ka as well.The primary results show that there exists relatively intense erosion on the Loess Plateau in the recent geological past,and the surface erosion in the glacial periods is mildly stronger than that in the interglacial periods.
The Kumtagh Desert is one of the eight biggest deserts in China.In this study,33 representative surface sediment samples were collected from Kumtagh Desert and analyzed in the laboratory to obtain composition of heavy mineral and content of geochemical elements.Results show that there are various kinds of heavy minerals in these samples,with large content of epidote and hornblende.Si and Al take up a large part of chemical composition.Compared with the average composition of geochemical elements of the upper continental crust(UCC),all elements except Si and Ca are depleted to a certain degree;Fe,Mg,Ca,P,Ti and Mn have high coefficients in their contents.Mineral composition of the samples of the Kumtagh Desert has a similarity with that of rocks of Altyn Tagh,surface sediments of the alluvial/fluvial fans of the Aityn Tagh and that of the Taklamakan Desert,indicating that one major source of the Kumtagh Desert sediments is located in Altyn Tagh.Alluvial deposits and lake sediments in Aqik valley and lower reaches of the Sule River are prone to be eroded and transported by the strong northeasterly wind to the Kumtagh Desert,as a result these places form another source of surface deposits of the Kumtagh Desert.A-CN-K ternary diagram shows that a weak chemical weathering by loss of Na and K occurred in these sediments,while other geochemical elements was in a less weathering or leaching process.A-CNK-FM ternary diagram suggests that Fe and Mg have distinct chemical differentiation.Physical weathering process makes it easy for mafic minerals to be eroded and enriched in fine particles,thus coarse desert sand particles can be relatively depleted in Fe and Mg.Mineral and geochemical composition of sediments in arid regions with less chemical weathering are mostly effected by physical processes.
Prehistoric human had moved forward northeast margin of Tibetan Plateau three times since Late Pleistocene,these activities are closely related to environmental evolution.The first expansion took place in 40-30 kaBP under warm-humid climate background;later,owing to the hard natural environment of Last Glacial Maximum,human activities have greatly shrunk at the plateau,and the cultural gap emerged.The rapid improvement of the natural environment driven the second expansion moved forward to the northeast margin of the Tibetan Plateau in the last deglaciation,then,persistent warm-humid climate is the guarantee of human survival and diffusion at the plateau.Majiayao culture at the east neighbourhood in 6-4 kaBP,under Holocene megathermal period background,came into the northeast of the Tibetan Plateau again,promoted the residents living on the Plateau before the end of Paleolithic and entered Neolithic Age,the social nature generated a huge progress.
The field work found that there existed three abrupt lake regressions in the Fenhe River Graben Basins during the middle-late Quaternary,which were consistent with the development of paleosols S8,S5 and S1.This indicates that those regressions are not the results of the dry climate but due to the neotectonic movement.The basins experienced slow transgressions when the loess-paleosols between S11-S8,S8-S5 and S5-S1 developed,and sank after S1 had formed.Based on these discoveries and previously revealed data about the activities of the upper mantle in the deep earth around this region,the paper puts forward a hypothesis that can explain how the lake transgression-regression cycles took place under the control of the neotectonic movement.The morpho-sedimentary characteristics are the results and responses of the activities of the upper mantle in the deep earth.
This paper discusses current concept of water resources carrying capacity.Furthermore,different definitions are compared and relations among these conceptions are analyzed in this study.It is suggested that the definition should consider abundant practicability besides on ecology,environment and sustainable development.Meanwhile "reasonable development scale" is applied to describe the conception of water resources carrying capacity.Based on the definition,the influences of water saving operations are analyzed,and a new calculation system of water resources carrying capacity is suggested to employ advanced evolution algorithms.This paper uses the model to carry out the research into water resources in the Liaohe River Basin,and the results show that the model is efficient.
This review summarizes main research findings in soil fauna eco-geography in China in the past 30 years.The subject areas and main results were overviewed including biodiversity and eco-geography distribution of soil fauna communities.Studies of ecological distributions of soil fauna and dynamics are presented in a wide range from tropical,subtropical to temperate regions,and in categories from forest,grassland,desert,wetland,farmland to urban ecosystems,the responses and indications of soil fauna to soil environments.Effects of intensive disturbance such as fire,grazing,farming,fertilization on soil fauna include sensitive and rare groups(e.g.nematode) and community indexes.The functions of soil fauna were discussed including environmental construction,environment purification,litter decomposition and elements cycles.This paper also involves the interactions between soil fauna and other biota in soil ecosystems and linking between aboveground and belowground diversity and the effects of globe change on soil fauna community in China.
In this study,investigations were conducted on residues of organochlorine pesticides(OCPs) in soils in Zhanjiang city,China.A total of 61 soil samples were collected from sites which were representative of the region for analysis of contents of OCPs.And with the aid of multi-variate geostatistics and GIS,residues and spatial distributions of 17 types of OCPs were analyzed.Results show that the 17 OCPs were detected,various in contents of all the soil samples.HCHs and DDTs residues were below the criteria of the national standards for soil environment quality.Residue content of β-HCH was the highest among HCHs,indicating some recent input of HCH to soils,while for DDT,no sign of new input was found.Principal component analysis demonstrated that the 17 OCPs in the soil may have 6 major contributors,corresponding respectively to the use of industrial HCH and lindane,plant diseases and insect pests and the pesticide use,etc.By means of ordinary Kriging interpolation,studies on spatial distribution of OCPs showed that the 17 OCPs varied greatly in spatial distribution between types.
The distribution of Picea crassifolia is affected by environmental conditions.Quantifying evaluation of the relationship between the distribution of Picea crassifolia and its habitat is significant for managing and restoring the damaged forest ecosystem,but there has been a lack of effective methods for quantitative evaluation.The northern slope of Qilian Mountains in Northwest China was selected as the study area and Picea crassifolia,the dominant species in the study area,was the core of the study.Based on digital elevation model(DEM) and inventory data of Picea crassifolia distribution,the niche space of Picea crassifolia has quantitatively been defined by the spatial analysis of geographic information system.Results show that the borders of the niche space are delineated by border functions.Generally,the niche space is July mean temperature:8.5 oC < TJuly < 14 oC,and the annual precipitation is 300 mm < Pannual < 620 mm.The range of elevation of the forest is from 2576 to 3344 m and its aspect is NNW and NNE.The range of slope of the forest is from 6o to 39o.The relationship between the slope and distribution frequency of Picea crassifolia is fit for Gauss function.
