STUDY ON THE SPATIAL PATTERNS OF LAND-USE CHANGE AND ANALYSES OF DRIVING FORCES IN NORTHEASTERN CHINA DURING 1990-2000

Land-use change is an important aspect of global environment change.It i s,in a sense,the direct result of human activities influencing our physical environment.Supported by the dynamic serving system of nation al resources,including both the environment data base and GIS technology,this paper a nalyzed the land-use change in north eastern Chi-na in the past ten years(1990-2000).It divides northeastern China into five land-use zones based on the dynamic de-gree(DD)of land-use:woodland /grassland -a rable land conversion zone,dry land-paddy field conversion zone,ur-ban expansion zone,interlocked zon e of farming and pasturing,and recla mation and abandoned zone.In the past ten years,land-use change of northeastern China can be generalized as follo ws:increase of cropland area was obvious,pad-dy field and dry land increased by 74.9and 276.0thousand ha respectively;urban area expanded rapidly,area o f town and rural residence increased by 76.8thousand ha;area of forest and grassland decreased sharply with the amo unt of1399.0and 1521.3thousand ha respec tively;area of water body and unused land increased by 148.4and 513.9thou-sand ha respectively.Besides a comp rehensive analysis of the spatial patterns of land use,this paper also di scusses the driving forces in each land-use dynamic zones.The study shows that some k ey biophysical factors affect consp icuously the conversion of different land-use ty pes.In this paper,the relationship s between land-use conversion and DEM,accumulat-ed temperature(≥10℃)and precipitation were analysed and represented.We conclude that the la nd-use changes in north-east China resulted from the change o f macro social and economic factors a nd local physical elements.Rapid population growth and management changes,in so me sense,can explain the shaping of woodland /grassland -cropland conve rsion zone.The conversion from dry land to paddy field in the dry land -paddy fie ld conversion zone,apart from the ph ysical elements change promoting the expan sion of paddy field,results from two reasons:one is that the implementation of mar-ket-economy in China has given farme rs the right to decide what they plant and how they plant their crops,the other fac-tor is originated partially from the change of dietary habit with the social and economic development.The con version from paddy field to dry land is caused prim arily by the shortfall of irrigation water,which in turn is caused by poor water alloca-tion managed by local governments.T he shaping of the reclamation and abandoned zone is partially due to the la ck of environ-ment protection consciousness amon g pioneer settlers.The reason for th e conversion fromgrassland to cropl and is the relative-ly higher profits of farming than that of pasturing in the interlocked zon e of farming and pasturing.In northeastern China,the rapid expansion of built-up areas results from two factors:the first is its small number of towns;the second comes from the huge potential for expansio n of existing towns and cities.It is n oticeable that urban expansion in th e northeastern China is characterized by gentle top ographic relief and low population d ensity.Physiognomy,transportati on and economy exert great influences on the urban e xpansion.

SPATIAL CORRELATION ANALYSIS OF CROP YIELD IN THE MIDDLE AND WEST OF JILIN PROVINCE

In this paper,spatial correlation of crop yield in the middle and west of Jilin Province is analyzed by us-ing the method of geostatistics semivariogram,taking the NDVI of NOAA/AVHRR spectrum data as the regionalized vari-able,aiming to provide theory and practical basis for field sampling of crop yield estimation using remote sensing.The ratio of nugget variance and sill of semivariograms are 21.1% and 9.7% in the west and middle regions in Jilin Province respectively.This shows that the crop yields are spatially correlated.The degree and range of correlation are far different in the different situations.In the west test region,the range is 49.9 km and the sill is 0.00019.In the middle testre-gion,the range is 16.5 km and the sill is0.00453.The dissimilarity in the western test region is larger than that in the middle one.The range in which the correlation existed of the former is far larger than the later.Different character is tics of spatial correlation of crop yield are decided by the environmental factors.Samples for crop yield estimation should be extracted according to the characteristic of spatial distribution of crop yield to promote the efficiency of sampling.

ESTIMATION OF ATMOSPHERIC INPUT OF MERCURY TO SOUTH LAKE AND JINGYUE POOL

Taking South Lake and Jingyue Pool in Changchun as examples, we determined particulate Hg in ambient air and Hg concentration in precipitation. Results indicated that particulate Hg in air and Hg concentration in precipitation in both sites in nonheating period were lower than that in heating period, which is influenced by coal combustion. The annual particulate Hg concentrations of South Lake and Jingyue Pool were 0.254ng/m3 and 0.109ng/m3. The yearly average Hg concentrations in precipitation were 0.268μg/L(South Lake) and 0.108μg/L(Jingyue Pool). The higher particulate Hg concentration in air and Hg concentration in precipitation in South Lake than that of Jingyue Pool indicated that mercury deposition was influenced by anthropogenic sources(especially from coas combustion). Hg concentration in precipitation is related with particulate Hg in the atmosphere. Dry deposition fluxes were estimated by using dry deposition model on the base of particulate Hg concentrations in the atmosphere, they were 35.5μg/(m2.a) for South lake and 15.3μg/(m2.a) for Jingyue Pool. Combined with precipitation amount, wet deposition fluxes were estimated in these two sites, 152.2μg/(m2.a) for South Lake and 61.2μg/(m2.a) for Jingyue Pool. Atmospheric Hg deposition fluxes were 160.2g/a for South Lake and 328.62g/a for Jingyue Pool.

STUDY ON THE OPTIMUM PATTERN OF DAQIN G URBAN SPATIAL STRUCTURE

Daqing is a mining city that was set up on wetland by exploiting and processing petroleum.This paper points out that net-group urban system is the optimization mode for Daqin g urban spatial structure through an alyzing and appraising the present situation,c haracteristics,advantages and dis advantages of Daqing spatial structure.And the best way of optimizing Daqing urban spatial structure is to adopt sustainable development strategy,establish th e coordinated grade structure of urban system,con struct developed towns net system,p refect the function structure of the towns at all levels,make full use of resources an d strengthen environmental protection.Spatial structure of Daqing must be according-ly adjusted in order to adapt to the tr ansformation of future economy types and functions.Based on the foundation of keep-ing net group,the development shoul d be from disperse to moderate centra lization in order to give prominence to the multi-function of the central city.Constr ucting ruralizing city should be the future goal of Daqing City.

Plan of Using Modern Agriculture High-New Information Technology for Building Stable Nation Commercial Grain and Green Agriculture Base of China

The North-East China is nation commercial grain base of China.It provides important grain supply for other areas of the country every year.The nation and modern farmers are looking for advanced technological solutions to increase production and preserve environment.Considering of this aim,this paper introduce a new planning that using 3S technology to develop precision farming,explaining its technology frame,operation steps and advantages.On the other hand,this paper also introduce the concept of precision farming and discusses the role of 3S technology as a data collection,management and analysis tool.