Scale dependence of forest fragmentation and its climate sensitivity in a semi-arid mountain:Comparing Landsat,Sentinel and Google Earth data

Landscape fragmentation is generally viewed as an indicator of environmental stresses or risks,but the fragmentation intensity assessment also depends on the scale of data and the definition of spatial unit.This study aimed to explore the scale-dependence of forest fragmentation intensity along a moisture gradient in Yinshan Mountain of North China,and to estimate environmental sensitivity of forest fragmentation in this semi-arid landscape.We developed an automatic classification algorithm using simple linear iterative clustering(SLIC)and Gaussian mixture model(GMM),and extracted tree canopy patches from Google Earth images(GEI),with an accuracy of 89.2%in the study area.Then we convert the tree canopy patches to forest category according to definition of forest that tree density greater than 10%,and compared it with forest categories from global land use datasets,FROM-GLC10 and GlobeLand30,with spatial resolutions of 10 m and 30 m,respectively.We found that the FROM-GLC10 and GlobeLand30 datasets underestimated the forest area in Yinshan Mountain by 16.88%and 21.06%,respectively;and the ratio of open forest(OF,10%<tree coverage<40%)to closed forest(CF,tree coverage>40%)areas in the underestimated part was 2:1.The underestimations concentrated in warmer and drier areas occupied mostly by large coverage of OFs with severely fragmented canopies.Fragmentation intensity of canopies positively correlated with spring temperature while negatively correlated with summer precipitation and terrain slope.When summer precipitation was less than 300 mm or spring temperature higher than 4℃,canopy fragmentation intensity rose drastically,while the forest area percentage kept stable.Our study suggested that the spatial configuration,e.g.,sparseness,is more sensitive to drought stress than area percentage.This highlights the importance of data resolution and proper fragmentation measurements for forest patterns and environmental interpretation,which is the base of reliable ecosystem predictions with regard to the future climate scenarios.

Climatic implications in earlywood and latewood width indices of Chinese pine in north central China

Latewood width(LWW)indices of trees are considered a reliable proxy of summer precipitation in the Northern Hemisphere.However,the strong coupling and high correlation between earlywood width(EWW)and LWW indices often prevent registration of climate signals of the LWW index.In this study,328-year-long earlywood width and latewood width chronologies were developed from Chinese pine at two sites in the Hasi Mountains,north central China.The climate responses of these chronologies were analyzed and the LWW index used to derive sum-mer precipitation signals.Correlation analyses showed that LWW was particularly influenced by earlywood growth and recorded stronger climate signals of the previous year as EWW,rather than those of the current year with infrequent summer climate signals.However,after removing the effect of earlywood growth using a simple regression model,the adjusted LWW chronology(LWW_(adj))showed a strong relationship with July precipitation in dry years.This suggests that the LWW_(adj) chronology has the potential to be used to investigate long-term variability in summer precipitation in drought-limited regions.

Spatial Pattern of Cotton Yield Variability and Its Response to Climate Change in Cotton Belt of Pakistan

Cotton is a revenue source for cotton-producing countries;as the second-largest crop in Pakistan,it significantly contributes to its economy.Over the past few decades,cotton productivity has become unstable in Pakistan,and climate change is one of the main factors that impact cotton yield.Due to climate change,it becomes very important to understand the change trend and its impact on cotton yield at the regional level.Here,we investigate the relationship of standardized cotton yield variability with the variability of climate factors using a 15-yr moving window.The piecewise regression was fitted to obtain the trend-shifting point of climate factors.The results show that precipitation has experienced an overall decreasing trend of–0.64 mm/yr during the study period,with opposing trends of–1.39 mm/yr and 1.52 mm/yr before and after the trend-shifting point,respectively.We found that cotton yield variability increased at a rate of 0.17%/yr,and this trend was highly correlated with the variability of climate factors.The multiple regression analysis explains that climate variability is a dominant factor and controlled 81%of the cotton production in the study area from 1990 to 2019,while it controlled 73%of the production from 1990 to 2002 and 84%from 2002 to 2019.These findings reveal that climate factors affact the distinct spatial pattern of changes in cotton yield variability at the tehsil level.

Winter-spring minimum temperature variations inferred from tree-ring δ^(13)C in southeastern China

Long-term temperature variations inferred from high-resolution proxies provide an important context to evaluate the intensity of current warming.However,tem-perature reconstructions in humid southeastern China are scarce and particularly lack long-term data,limiting us to obtain a complete picture of regional temperature evolution.In this study,we present a well-verified reconstruction of winter-spring(January–April)minimum temperatures over southeastern China based on stable carbon isotopic(δ^(13)C)records of tree rings from Taxus wallichiana var.mairei from 1860 to 2014.This reconstruction accounted for 56.4%of the total observed variance.Cold periods occurred during the 1860s–1910s and 1960s–1970s.Although temperatures have had an upward trend since the 1920s,most of the cold extremes were in recent decades.The El Niño-Southern Oscillation(ENSO)variance acted as a key modulator of regional winter-spring minimum temperature variability.However,teleconnections between them were a nonlinear process,i.e.,a reduced or enhanced ENSO variance may result in a weakened or intensified temperature-ENSO relationship.

Spatial and temporal variations of vegetation cover and the relationships with climate factors in Inner Mongolia based on GIMMS NDVI3g data

Variation in vegetation cover in Inner Mongolia has been previously studied by the remote sensing data spanning only one decade. However, spatial and temporal variations in vegetation cover based on the newly released GIMMS NDVI3g data spanning nearly thirty years have yet to be analyzed. In this study, we applied the methods of the maximum value composite （MVC） and Pearson＇s correlation coefficient to analyze the variations of vegetation cover in Inner Mongolia based on GIMMS NDVI3g data spanning from 1982 to 2013. Our results indicate that the normalized difference vegetation index （NDVI） increased at a rate of 0.0003/a during the growing seasons despite of the drier and hotter climate in Inner Mongolia during the past three decades. We also found that vegetation cover in the southern agro-pastoral zone significantly increased, while it significantly decreased in the central Alxa. The variations in vegetation cover were not significant in the eastern and central regions. NDVI is positively correlated with precipitation （r=0.617, P=0.000） and also with air temperature （r=0.425, P=0.015）, but the precipitation had a greater effect than the air temperature on the vegetation variations in Inner Mongolia.

Relationship Between Changes of River-lake Networks and Water Levels in Typical Regions of Taihu Lake Basin,China

The typical regions of the Taihu Lake Basin,China,were selected to analyze the variation characteristics of river-lake networks under intensive human activities.The characteristics of the fractal dimension of river networks and lakes for different periods were investigated and the influences of river system evolution on water level changes were further explored through the comparison of their fractal characters.The results are as follows:1) River network development of the study area is becoming more monotonous and more simple;the number of lakes is reducing significantly,and the water surface ratio has dropped significantly since the 1980s.2) The box dimension of the river networks in all the cities of the study area decreased slowly from the 1960s to the 1980s,while the decrease was significant from the 1980s to the 2000s.The variations of lake correlation dimension are similar to those of the river network box dimensions.This is unfavorable for the storage capacity of the river networks and lakes.3) The Hurst exponents of water levels were all between 0.5 and 1.0 from the 1960s to the 1980s,while decreased in the 2000s,indicating the decline in persistence and increase in the complexity of water level series.The paper draws a conclusion that the relationship between the fractal dimension of river-lake networks and the Hurst exponents of the water level series can reveal the impacts of river system changes on flood disasters to some extent:the disappearance of river networks and lakes will increase the possibility of flood occurrence.

Three Types of Spatial Function Zoning in Key Ecological Function Areas Based on Ecological and Economic Coordinated Development: A Case Study of Tacheng Basin, China

Three types of spatial function zoning is an effective measure for regional environmental protection and orderly development.For ecological and economic coordinated development, spatial function zones should be divided scientifically to clear its direction of development and protection. Therefore, based on ecological constraints, a beneficial discussion would be about the key ecological function areas adopting the concept of ecological protection restriction and supporting socioeconomic development for spatial function zoning. In this paper, the researchers, taking Tacheng Basin, Xinjiang of China as an example, choose township as basic research unit and set up an evaluation index system from three aspects, namely, ecological protection suitability, agricultural production suitability, and urban development suitability, which are analyzed by using spatial analysis functions and exclusive matrix method. The results showed that: 1) This paper formed a set of multilevel evaluation index systems for three types of spatial function zoning of the key ecological function areas based on a novel perspective by scientifically dividing Tacheng Basin into ecological space, agricultural space, and urban space,which realized the integration and scientific orientation for spatial function at the township scale. 2) Under the guidance of three types of spatial pattern, the functional orientation and suggestions of development and protection was clearly defined for ecological protection zones,ecological economic zones, agricultural production zones, and urban development zones. 3) A new idea of space governance is provided to promote the coordinated and sustainable development between ecology and economy, which can break the traditional mode of thinking about regional economic development, and offers a scientific basis and reference for macro decision-making.

A New Temperature Channel Selection Method Based on Singular Spectrum Analysis for Retrieving Atmospheric Temperature Profiles from FY-4A/GIIRS

Hyperspectral data have important research and application value in the fields of meteorology and remote sensing.With the goal of improving retrievals of atmospheric temperature profiles,this paper outlines a novel temperature channel selection method based on singular spectrum analysis(SSA)for the Geostationary Interferometric Infrared Sounder(GIIRS),which is the first infrared sounder operating in geostationary orbit.The method possesses not only the simplicity and rapidity of the principal component analysis method,but also the interpretability of the conventional channel selection method.The novel SSA method is used to decompose the GIIRS observed infrared brightness temperature spectrum(700-1130 cm-1),and the reconstructed grouped components can be obtained to reflect the energy variations in the temperature-sensitive waveband of the respective sequence.At 700-780 cm-1,the channels selected using our method perform better than IASI(Infrared Atmospheric Sounding Interferometer)and Cr IS(Cross-track Infrared Sounder)temperature channels when used as inputs to the neural network retrieval model.

Strong controls of daily minimum temperature on the autumn photosynthetic phenology of subtropical vegetation in China

Background:Vegetation phenology research has largely focused on temperate deciduous forests,thus limiting our understanding of the response of evergreen vegetation to climate change in tropical and subtropical regions.Results:Using satellite solar-induced chlorophyll fluorescence(SIF)and MODIS enhanced vegetation index(EVI)data,we applied two methods to evaluate temporal and spatial patterns of the end of the growing season(EGS)in subtropical vegetation in China,and analyze the dependence of EGS on preseason maximum and minimum temperatures as well as cumulative precipitation.Our results indicated that the averaged EGS derived from the SIF and EVI based on the two methods(dynamic threshold method and derivative method)was later than that derived from gross primary productivity(GPP)based on the eddy covariance technique,and the time-lag for EGSsif and EGSevi was approximately 2 weeks and 4 weeks,respectively.We found that EGS was positively correlated with preseason minimum temperature and cumulative precipitation(accounting for more than 73%and 62%of the study areas,respectively),but negatively correlated with preseason maximum temperature(accounting for more than 59%of the study areas).In addition,EGS was more sensitive to the changes in the preseason minimum temperature than to other climatic factors,and an increase in the preseason minimum temperature significantly delayed the EGS in evergreen forests,shrub and grassland.Conclusions:Our results indicated that the SIF outperformed traditional vegetation indices in capturing the autumn photosynthetic phenology of evergreen forest in the subtropical region of China.We found that minimum temperature plays a significant role in determining autumn photosynthetic phenology in the study region.These findings contribute to improving our understanding of the response of the EGS to climate change in subtropical vegetation of China,and provide a new perspective for accurately evaluating the role played by evergreen vegetation in the regional carbon budget.

Variations in Optical Scattering and Backscattering by Organic and Inorganic Particulates in Chinese Lakes of Taihu, Chaohu and Dianchi

This study presents an investigation of the scattering and backscattering properties of the particulates in three Chinese inland lakes(the Taihu Lake, the Chaohu Lake and the Dianchi Lake) based on in situ measurements taken at 119 sites. We modeled the particulate scattering spectra using a wavelength-dependent power-law function, finding that the power-law exponents in the Taihu Lake and the Chaohu Lake differ from those in the Dianchi Lake but are similar to the values in the U.S. coastal waters. In contrast to the open ocean, the backscattering properties in the three lakes can not be determined only from chlorophyll-a concentration. The backscattering ratio spectra exhibit a wavelength dependence feature in all three lakes, generally decreasing with the increasing wavelength. Analysis results of the correlations between the backscattering ratio and the individual water quality parameters clearly show that there are distinctive relations among the three lakes, attributed primarily to different compositions of optically active materials in the three lakes. Analysis of the mass-specific scattering and backscattering coefficients shows that the coefficients at wavelength 532 nm in the Taihu Lake and Chaohu Lake are similar, but they are apparently different from those in the Dianchi Lake. Lastly, Model I multiple linear regressions were adopted to partition the mass-specific cross-sections for scattering and backscattering into organic and inorganic cross-sections to further interpret the scattering and backscattering properties. The relative contribution of organic and inorganic particulates to scattering and backscattering is clearly different among the three lakes. The scattering and backscattering properties of the particulates in the three inland lakes vary significantly based on our collected data. The results indicated that the existing semi-analytical water quality retrieval models of the Taihu Lake can not be applied perfectly to the Chaohu Lake and the Dianchi Lake.

Impact of GCP distribution on the rectification accuracy of Landsat TM imagery in a coastal zone

The purpose is to explore the effect of the spatial distribution of ground control points （GCPs） on the accuracy of imagery rectification. Both area-distributed and linearly distributed GCPs were used to rectify a Landsat TM image of a coastal zone. Rectification accuracy was checked against 99 independent points over the intertidal mudflats with no ground control. Results indicate that the root-mean-square error of residuals over these areas is several times larger than its GCPs-measured counterpart. If the GCPs are spatially dispersed over an area, residuals fluctuate but increase steadily with distance to the source of control in easting （R^2= 0. 827）. in northing they fluctuate around 150 m until 15 km, beyond which they rise steadily at a small range of fluctuation. These residuals are less predictable from distance to the source of control than in easting （R^2= 0.517 ）. If the GCPs are distributed along a control line, residuals rise with distance to it linearly and predictably （R^2 = 0. 877） in the direction perpendicular to it. In a direction parallel to it, the distance has little impact on rectification residuals.

Study of the intensity and driving factors of land use/cover change in the Yarlung Zangbo River, Nyang Qu River, and Lhasa River region, Qinghai-Tibet Plateau of China

Land use/land cover(LULC) is an important part of exploring the interaction between natural environment and human activities and achieving regional sustainable development. Based on the data of LULC types(cropland, forest land, grassland, built-up land, and unused land) from 1990 to 2015, we analysed the intensity and driving factors of land use/cover change(LUCC) in the Yarlung Zangbo River,Nyang Qu River, and Lhasa River(YNL) region, Qinghai-Tibet Plateau of China, using intensity analysis method, cross-linking table method, and spatial econometric model. The results showed that LUCC in the YNL region was nonstationary from 1990 to 2015, showing a change pattern with "fast-slow-fast" and "U-shaped". Built-up land showed a steady increase pattern, while cropland showed a steady decrease pattern. The gain of built-up land mainly came from the loss of cropland. The transition pattern of LUCC in the YNL region was relatively single and stable during 1990–2015. The transition pattern from cropland and forest land to built-up land was a systematic change process of tendency and the transition pattern from grassland and unused land to cropland was a systematic change process of avoidance. The transition process of LUCC was the result of the combined effect of natural environment and social economic development in the YNL region. This study reveals the impact of ecological environment problems caused by human activities on the land resource system and provides scientific support for the study of ecological environment change and sustainable development of the Qinghai-Tibet Plateau.

Change of Flood Patterns in China under the Influences of Climate Change and Human Activities

Based on the flood affected area （FA） data of the provinces in China from 1950 to 2005, the article discusses the change of the flood patterns in China, and investigates its relationship with climate change and human activities. The flood center shifted from North China and the Yangtze-Huaihe basin in the 1950s towards the south, north and west of China, and located in the south of the Yangtze River and South China after the 1990s. The FA in the western provinces was continuously on the rise since the 1950s. There are two characteristics for the future flood pattem in China. The pattern of ＂flood in the south and drought in the north＂ depends on the north-south shift of the maximum rainfall region in eastern China. The flood intensification to the west of Hu Huanyong＇s line mainly results from the increase of rainfall, extreme precipitation and the melting of glaciers under the background of human activity magnification.

Patterns of Clay Minerals Transformation in Clay Gouge, with Examples from Revers Fault Rocks in Devonina Niqiuhe Formation in The Dayangshu Basin

The role of authigenic clay growth in clay gouge is increasingly recognized as a key to understanding the mechanics of berittle faulting and fault zone processes,including creep and seismogenesis,and providing new insights into the ongoing debate about the frictional strength of brittle fault(Haines and van der Pluijm,2012).However,neither the conditions nor the processes which

Competition,spatial pattern,and regeneration of Haloxylon ammodendron and Haloxylon persicum communities in the Gurbantunggut Desert,Northwest China

Competition,spatial pattern,and regeneration are important factors affecting community composition,structure,and dynamics.In this study,we surveyed 300 quadrats from three dunes(i.e.,fixed dunes,semifixed dunes,and mobile dunes)in the Gurbantunggut Desert,Northwest China,from late May to early June in 2021.The intraspecific and interspecific competition,spatial pattern,and regeneration of Haloxylon ammodendron and Haloxylon persicum were studied using the Hegyi competition index and point pattern analysis methods.The results showed that the optimal competition distance of the objective tree in the H.ammodendron and H.persicum communities was 6 m.The intraspecific and interspecific competition of H.ammodendron was the greatest in fixed dunes,while the competition intensity of H.persicum in semifixed dunes and mobile dunes was greater than that in fixed dunes.The order of competition intensity of the two populations was seedlings>saplings>adults,and the competition intensity gradually decreased with the increase in plant diameter.The spatial distribution pattern of the three life stages of H.ammodendron and H.persicum was random,and there were no correlations between seedlings and saplings,adults and saplings,and seedlings and adults.The density of regenerated seedlings and saplings of H.ammodendron in the three dunes followed the order of fixed dunes>semifixed dunes>mobile dunes,and that of H.persicum in the three dunes followed the order of mobile dunes>semifixed dunes>fixed dunes.Therefore,when artificially planting H.ammodendron and H.persicum for sand control,the planting interval should be 6 m,and seedlings should be planted next to adults to minimize the competition between plants,which can promote the renewal of H.ammodendron and H.persicum and the stabilization of the ecosystem.

Fetch effect on the developmental process of aeolian sand transport in a wind tunnel

As the sand mass flux increases from zero at the leading edge of a saltating surface to the equilibrium mass flux at the critical fetch length,the wind flow is modified and then the relative contribution of aerodynamic and bombardment entrainment is changed.In the end the velocity,trajectory and mass flux profile will vary simultaneously.But how the transportation of different sand size groups varies with fetch distance is still unclear.Wind tunnel experiments were conducted to investigate the fetch effect on mass flux and its distribution with height of the total sand and each size group in transportation.The mass flux was measured at six fetch length locations(0.5,1.2,1.9,2.6,3.4 and 4.1 m)and at three free-stream wind velocities(8.8,12.2 and 14.5 m/s).The results reveal that the total mass flux and the mass flux of each size group with height can be expressed by q=aexp(–bh),where q is the sand mass flux at height h,and a and b are regression coefficients.The coefficient b represents the relative decay rate.Both the relative decay rates of total mass flux and each size group are independent of fetch length after a quick decay over a short fetch.This is much shorter than that of mass flux.The equilibrium of the relative decay rate cannot be regarded as an equilibrium mass flux profile for aeolian sand transport.The mass fluxes of 176.0,209.3 and 148.0μm size groups increase more quickly than that of other size groups,which indicates strong size-selection of grains exists along the fetch length.The maximal size group in mass flux(176.0μm)is smaller than the maximal size group of the bed grains(209.3μm).The relative contribution of each size group to the total mass flux is not monotonically decreasing with grain size due to the lift-off of some small grains being reduced due to the protection by large grains.The results indicate that there are complex interactions among different size groups in the developmental process of aeolian sand transport and more attention should be focused on the fetch effect because it has different influences on the total mass flux,the mass flux profile and its relative decay rate.

Re-Os Isotopic Age of Molybdenite of the Jingren Deposit and its Mineralogical Significance of Magnetite,Pyrite and Chalcopyrite

The Jingren deposit is part of the Qimantage metallogenic belt within the eastern Kunlun orogenic belt,the largest metallogenic belt in Qinghai Province,northwestern China.Exploration data show that the metal resources of the Jingren deposit are greater than 93000 t in a mining area of 76.15 km2,which indicates significant exploration potential in the near future.Three W–E-trending faults,F1-3,dominate the extension of the mineralization zone,which consists of chalcopyrite,pyrite,magnetite,galena,sphalerite,and molybdenite as well as bismuth-bearing minerals.The deposit contains a large amount of late Triassic intrusive rocks,however,previous research did not reach a consensus on the timing or the origin of the mineralization owing to a lack of geochronological data and poor exposure conditions.In the present study,Re-Os isotopic dating from six molybdenite samples collected from a borehole of the granodiorite in the Jingren deposit using negative thermal ionization mass spectrometry(NTIMS)showed 187 Re and 187 Os concentrations of 0.26–4.40 ppm and 1.03–16.46 ppb,respectively,with an initial 187 Os/188 Os value of 0.06±0.19.This proves that the Jingren deposit has a metallogenic age of(225±4)Ma and is the product of united mineralization of the Qimantage metallogenic belt and that the Jingren deposit might actually be an Indosinian metallogeny.In addition,the Re content of these samples,at 0.42 ppm to 7.00 ppm shows that the mineralization was derived mainly from a crustal source.Furthermore,electron probe microanalysis(EPMA)conducted on chalcopyrite obtained from 22 metallic mineral samples revealed(Fe+Cu)/S ratios of 1.801–1.947 with an average of 1.852,which is lower than the ideal value(1.875).Besides,the main ore body formed in a relatively higher temperature environment than the surrounding rocks in the Jingren deposit.These data indicate that the Jingren deposit formed in a metallogenic environment at lower temperature.Moreover,according to the TiO_(2)-Al_(2)O_(3)-(MgO+MnO)and TiO_(2)-Al_(2)O_(3)-MgO genetic classification diagram for magnetite,the Jingren deposit most likely belongs to the skarn family.In addition,the Co-Ni-As genetic classification diagram of the pyrite indicates sedimentary and skarn genetic characteristics.

Spatial Pattern of Chinese Tourism Development and Its Mechanism Based on Different Spatial-temporal Scales:Taking the Panel Data of China Mainland(1996-2010) for Example

By taking the panel data of China mainland from 1996 to 2010 for an example, this paper used ESDA, gravity center and standard deviation ellipse to analyze the spatial differences, combined with the impulse response function to propose the infl uence mechanism of spatial evolution. The results showed that the provincial tourism economy generally showed a random spatial distribution and the spatial differences had narrowed from 1996 to 2010. The differences of tourism development in east China are the largest, and differences of the middle China are the smallest. The gravity center of Chinese provincial tourism has shifted to the northwest, the HH district concentrated in the Yangtze River Delta and its surroundings, the LL district concentrated in west Chinese. The high-value areas of city tourism economy are broadly distributed in the right of line "Heihe–Tengchong", mainly concentrated in four plates. Compared with spatial differences of provincial tourism economy, those of city tourism economy were more signifi cant. Regional tourism resources and social economic factors are the two major factors that infl uence spatial differences of tourism economy, the objective rule and policy and institution also have a great impact on regional tourism development differences. Special events may have a certain impact on the pattern of the original; however, it cannot change the spatial pattern completely.

Risk Assessment and Zoning of Agricultural Drought Disaster in Heilongjiang Province

In this study,we first zoned the drought degree in the years from 1971 to 2000 in Heilongjiang Province by using precipitation anomaly equation as an indicator,and analyzed the temporal distribution characteristics and laws of arid disaster in different periods.Using the method of human being habitat risk assessment,we further studied and zoned the drought disaster risk index(DDRI)of maize cultivated in 74 stations in Heilongjiang Province via GIS software.The results showed that(1)the occurrence frequency of moderate and heavy drought in Heilongjiang Province was 1970s>1990s>1980s,and(2)the high risk area of drought disaster for maize production mainly assembled in Qiqihar and Daqing regions in west Heilongjiang Province,where agricultural drought should be highly concerned,while low risk and slight risk areas mainly distribute in middle areas and east plain areas in Heilongjiang Province.Our study provided basis for the defense of agricultural drought disaster.

Driving Force Analysis of Land Cover Change in Ulan Buh Desert Based on Markov Chain

The Ulan Buh Desert has a fragile natural environment, which is in the western part of Inner Mongolia arid climate zone and the farming and animal husbandry ecotone. In order to explore the driving force mechanism of the Land Cover Change, the paper constructed the natural-human driving force model by the Markov Chain based on Landsat MSS 1973, 1977 remote sensing image data, analyzed the naturalhuman driving force contribution rate to the Land Cover Change in Ulan Buh Desert. The results showed that in 1989-2013 the main driving force of the Ulan Buh Desert Land Cover Change is the natural factors, average contribution rate is 89.46%, then is the human driving force, the rate is 10.54%. The natural-human driving force contribution rate for every land cover type is different, in natural part, the minimum rate is saline-alkali land for 45.20%, while the maximum is sandy land(90.63%). The human driving force rate of forest land, grassland and water was negative, it shows that human factors slows down or hinder the growth of this kind of land cover. Because of the humanistic attribute, the natural effect of the cultivated land and construction land was abandoned, the rates of human driving are significantly different: the change of human driving force is 24.94%, while the change of construction land is 62.9%.