Land use and cover change(LUCC)is the most direct manifestation of the interaction between anthropological activities and the natural environment on Earth's surface,with significant impacts on the environment and ...Land use and cover change(LUCC)is the most direct manifestation of the interaction between anthropological activities and the natural environment on Earth's surface,with significant impacts on the environment and social economy.Rapid economic development and climate change have resulted in significant changes in land use and cover.The Shiyang River Basin,located in the eastern part of the Hexi Corridor in China,has undergone significant climate change and LUCC over the past few decades.In this study,we used the random forest classification to obtain the land use and cover datasets of the Shiyang River Basin in 1991,1995,2000,2005,2010,2015,and 2020 based on Landsat images.We validated the land use and cover data in 2015 from the random forest classification results(this study),the high-resolution dataset of annual global land cover from 2000 to 2015(AGLC-2000-2015),the global 30 m land cover classification with a fine classification system(GLC_FCS30),and the first Landsat-derived annual China Land Cover Dataset(CLCD)against ground-truth classification results to evaluate the accuracy of the classification results in this study.Furthermore,we explored and compared the spatiotemporal patterns of LUCC in the upper,middle,and lower reaches of the Shiyang River Basin over the past 30 years,and employed the random forest importance ranking method to analyze the influencing factors of LUCC based on natural(evapotranspiration,precipitation,temperature,and surface soil moisture)and anthropogenic(nighttime light,gross domestic product(GDP),and population)factors.The results indicated that the random forest classification results for land use and cover in the Shiyang River Basin in 2015 outperformed the AGLC-2000-2015,GLC_FCS30,and CLCD datasets in both overall and partial validations.Moreover,the classification results in this study exhibited a high level of agreement with the ground truth features.From 1991 to 2020,the area of bare land exhibited a decreasing trend,with changes primarily occurring in the middle and lower reaches of the basin.The area of grassland initially decreased and then increased,with changes occurring mainly in the upper and middle reaches of the basin.In contrast,the area of cropland initially increased and then decreased,with changes occurring in the middle and lower reaches.The LUCC was influenced by both natural and anthropogenic factors.Climatic factors and population contributed significantly to LUCC,and the importance values of evapotranspiration,precipitation,temperature,and population were 22.12%,32.41%,21.89%,and 19.65%,respectively.Moreover,policy interventions also played an important role.Land use and cover in the Shiyang River Basin exhibited fluctuating changes over the past 30 years,with the ecological environment improving in the last 10 years.This suggests that governance efforts in the study area have had some effects,and the government can continue to move in this direction in the future.The findings can provide crucial insights for related research and regional sustainable development in the Shiyang River Basin and other similar arid and semi-arid areas.展开更多
The Himalayan region has been experiencing stark impacts of climate change,demographic and livelihood pattern changes.The analysis of land use and land cover(LULC)change provides insights into the shifts in spatial an...The Himalayan region has been experiencing stark impacts of climate change,demographic and livelihood pattern changes.The analysis of land use and land cover(LULC)change provides insights into the shifts in spatial and temporal patterns of landscape.These changes are the combined effects of anthropogenic and natural/climatic factors.The present study attempts to monitor and comprehend the main drivers behind LULC changes(1999-2021)in the Himalayan region of Pithoragarh district,Uttarakhand.Pithoragarh district is a border district,remotely located in the north-east region of Uttarakhand,India.The study draws upon primary and secondary data sources.A total of 400 household surveys and five group discussions from 38 villages were conducted randomly to understand the climate perception of the local community and the drivers of change.Satellite imagery,CRU(Climatic Research Unit)climate data and climate perception data from the field have been used to comprehensively comprehend,analyze,and discuss the trends and reasons for LULC change.GIS and remote sensing techniques were used to construct LULC maps.This multifaceted approach ensures comprehensive and corroborated information.Five classes were identified and formed viz-cultivation,barren,settlement,snow,and vegetation.Results show that vegetation and builtup have increased whereas cultivation,barren land,and snow cover have decreased.The study further aims to elucidate the causes behind LULC changes in the spatially heterogeneous region,distinguishing between those attributed to human activities,climate shifts,and the interconnected impacts of both.The study provides a comprehensive picture of the study area and delivers a targeted understanding of local drivers and their potential remedies by offering a foundation for formulating sustainable adaptation policies in the region.展开更多
Understanding the trajectories and driving mechanisms behind land use/land cover(LULC)changes is essential for effective watershed planning and management.This study quantified the net change,exchange,total change,and...Understanding the trajectories and driving mechanisms behind land use/land cover(LULC)changes is essential for effective watershed planning and management.This study quantified the net change,exchange,total change,and transfer rate of LULC in the Jinghe River Basin(JRB),China using LULC data from 2000 to 2020.Through trajectory analysis,knowledge maps,chord diagrams,and standard deviation ellipse method,we examined the spatiotemporal characteristics of LULC changes.We further established an index system encompassing natural factors(digital elevation model(DEM),slope,aspect,and curvature),socio-economic factors(gross domestic product(GDP)and population),and accessibility factors(distance from railways,distance from highways,distance from water,and distance from residents)to investigate the driving mechanisms of LULC changes using factor detector and interaction detector in the geographical detector(Geodetector).The key findings indicate that from 2000 to 2020,the JRB experienced significant LULC changes,particularly for farmland,forest,and grassland.During the study period,LULC change trajectories were categorized into stable,early-stage,late-stage,repeated,and continuous change types.Besides the stable change type,the late-stage change type predominated the LULC change trajectories,comprising 83.31% of the total change area.The period 2010-2020 witnessed more active LULC changes compared to the period 2000-2010.The LULC changes exhibited a discrete spatial expansion trend during 2000-2020,predominantly extending from southeast to northwest of the JRB.Influential driving factors on LULC changes included slope,GDP,and distance from highways.The interaction detection results imply either bilinear or nonlinear enhancement for any two driving factors impacting the LULC changes from 2000 to 2020.This comprehensive understanding of the spatiotemporal characteristics and driving mechanisms of LULC changes offers valuable insights for the planning and sustainable management of LULC in the JRB.展开更多
Rapid urbanization creates complexity,results in dynamic changes in land and environment,and influences the land surface temperature(LST)in fast-developing cities.In this study,we examined the impact of land use/land ...Rapid urbanization creates complexity,results in dynamic changes in land and environment,and influences the land surface temperature(LST)in fast-developing cities.In this study,we examined the impact of land use/land cover(LULC)changes on LST and determined the intensity of urban heat island(UHI)in New Town Kolkata(a smart city),eastern India,from 1991 to 2021 at 10-a intervals using various series of Landsat multi-spectral and thermal bands.This study used the maximum likelihood algorithm for image classification and other methods like the correlation analysis and hotspot analysis(Getis–Ord Gi^(*) method)to examine the impact of LULC changes on urban thermal environment.This study noticed that the area percentage of built-up land increased rapidly from 21.91%to 45.63%during 1991–2021,with a maximum positive change in built-up land and a maximum negative change in sparse vegetation.The mean temperature significantly increased during the study period(1991–2021),from 16.31℃to 22.48℃in winter,29.18℃to 34.61℃in summer,and 19.18℃to 27.11℃in autumn.The result showed that impervious surfaces contribute to higher LST,whereas vegetation helps decrease it.Poor ecological status has been found in built-up land,and excellent ecological status has been found in vegetation and water body.The hot spot and cold spot areas shifted their locations every decade due to random LULC changes.Even after New Town Kolkata became a smart city,high LST has been observed.Overall,this study indicated that urbanization and changes in LULC patterns can influence the urban thermal environment,and appropriate planning is needed to reduce LST.This study can help policy-makers create sustainable smart cities.展开更多
Information on the dynamics of savannah is important to a country's plan to overcome the problems of uncontrolled development and environmental hazards. Taking the reserve partielle de Dosso, Niger as the case stu...Information on the dynamics of savannah is important to a country's plan to overcome the problems of uncontrolled development and environmental hazards. Taking the reserve partielle de Dosso, Niger as the case study area, this paper analyzed the long-term land use land cover change from 2002 to 2022. Satellite images were processed by using Google Earth Engine (GEE). Therefore, four major land cover classes were identified based on spectral characteristics of Land sat, namely, built-up, vegetation, cropland, bare land and water. The result revealed that barren and built-up areas increased at the expense of vegetation and water. From the four major land use land cover the large area is covered by vegetation which comprises about 192963.5 hectares followed by cropland and water consisting of 32506.43 and 1596.4 hectares respectively. The built-up area gained substantial area (most) during the study period. The reduction in some of the land cover/uses underlines the dangerous trend of the pressure poised by population growth and the changing functionality. Land cover change is influenced by a variety of societal factors operating on several spatial and temporal levels. The area estimates and spatial distributions of the LULC classes produced from the current study will assist local authorities, managers, and other stakeholders in decision-making and planning regarding forest land cover and uses.展开更多
Understanding the effects of land use/cover change(LUCC) on regional climate is critical for achieving land use system sustainability and global climate change mitigation. However, the quantitative analysis of the con...Understanding the effects of land use/cover change(LUCC) on regional climate is critical for achieving land use system sustainability and global climate change mitigation. However, the quantitative analysis of the contribution of LUCC to the changes of climatic factors, such as precipitation & temperature(P&T), is lacking. In this study, we combined statistical methods and the gravity center model simulation to quantify the effects of long-term LUCC on P&T in the Songnen Plain(SNP) of Northeast China from 1980–2018. The results showed the spatiotemporal variability of LUCC. For example, paddy field had the largest increase(15 166.43 km2) in the SNP, followed by dry land, while wetland had the largest decrease(19 977.13 km;) due to the excessive agricultural utilization and development. Annual average precipitation decreased at a rate of –9.89 mm per decade, and the warming trends were statistically significant with an increasing rate of 0.256°C per decade in this region since 1980. The model simulation revealed that paddy field, forestland, and wetland had positive effects on precipitation, which caused their gravity centers to migrate towards the same direction accompanied by the center of precipitation gravity, while different responses were seen for building land, dry land and unused land. These results indicated that forestland had the largest influence on the increase of precipitation compared with the other land use types.The responses in promoting the temperature increase differed significantly, being the highest in building land, and the lowest in forestland. In general, the analysis of regional-scale LUCC showed a significant reduction of wetland, and the increases in building land and cropland contributed to a continuous drying and rapid warming in the SNP.展开更多
This paper carries out quantitative analysis on the land use/cover (LU/C) change of 13anjin Binhai New Area in recent 10 years through using land use transition matrix from the three-stage LU/C classification maps o...This paper carries out quantitative analysis on the land use/cover (LU/C) change of 13anjin Binhai New Area in recent 10 years through using land use transition matrix from the three-stage LU/C classification maps of 2000, 2005 and 2010 drafted by means of the National Land Classification System of China based on Landsat TM satellite remote sensing image and the Tianjin Binhai New Area 1:50 000 relief maps. On this basis, the impact of such driving factors as the economy and population on LU/C is further analyzed. The results show that the area of the building land in Binhai New Area has increased significantly over the ten years, and the greenland, wetland, and shoals of high ecological value have been dramatically transformed into the building land and unused land for the development and construction, and the change is more significant in the later five years.展开更多
The objective of this work is to produce statistics that are going to show changes occurred in Brazil's ecosystems and these statistics are going to join the SEEA (Environmental-Economic Accounts System). It is bas...The objective of this work is to produce statistics that are going to show changes occurred in Brazil's ecosystems and these statistics are going to join the SEEA (Environmental-Economic Accounts System). It is based by a SEEA's methodology, diffused by UN (United Nations), which aims an approach between economic and environmental statistics, producing international comparability and conceptual uniformity to evaluate change process in land cover and land use that occurs in several countries. It is necessary to verifying the suitability of methodological procedures to Brazilian reality and the access to all information and files needed. The first step was analysing MODIS (Moderate Resolution Imaging Spectroradiometer) as orbital instrument on the purposed classification method. The choice of this sensor was made because of the product's quality and its capacity to generate images of a large area, though the challenge is to identify accurate Land usage's categories in images with a spatial resolution of approximately 250 m. After the final classification, the next step is to make a quantification and comparison of data from these different years using a 1 km2 grids, as proposed in an already used methodology by the European Environment Agency. This procedure will allow evaluate and identify the process of changing in each grid of the land cover and land use, and provide historical series of the chosen years.展开更多
Land cover is an impression of natural cover on surface of earth such as bare soil, river, grass etc. and utilization of these natural covers for various human needs and purposes by mankind is defined as land use. Lan...Land cover is an impression of natural cover on surface of earth such as bare soil, river, grass etc. and utilization of these natural covers for various human needs and purposes by mankind is defined as land use. Land cover identification, delineation and mapping is important for planning activities, resource management and global monitoring studies while baseline mapping and subsequent monitoring is done by application of land use to get timely information about quantity of land that has been used. The present study has been carried out in Dhund river watershed of Jaipur, Rajasthan which covers an area of about 1828 sq∙km. The minimum and maximum elevation of the area is found to be 214 m and 603 m respectively. Land use and land cover changes of three decades from 1991 to 2021 have been interpreted by using remotes sensing and GIS techniques. ArcGIS software (Arc map 10.2), SOI topographic map, Cartosat-1 DEM and satellite data of Landsat 5 and Landsat 8 have been used for interpretation of eleven classes. The study shows an increase in cultivated land, settlement, waterbody, open forest, plantation and mining due to urbanization because of increasing demands of food, shelter and water while a decrease in dense forest, river, open scrub, wasteland and uncultivated land has also been marked due to destruction of aforementioned by anthropogenic activities such as industrialization resulting in environmental degradation that leads to air, soil and water pollution.展开更多
Land use/cover change, which in China is characterized by urbanization resulting in a decrease in arable land in the east along with a large area of grassland being cultivated in the west, has been accelerated by rapi...Land use/cover change, which in China is characterized by urbanization resulting in a decrease in arable land in the east along with a large area of grassland being cultivated in the west, has been accelerated by rapid economic development in the last years. All of the above changes will affect sustainable development in the next century. The Chinese Academy of Sciences is conducting a study of land use/cover change over the last ten years based on the integration of remote sensing and GIS technology to establish a multitemporal database covering all of China. Fundamental data for land use/cover for the year 1996 has already been developed by the Chinese Academy of Sciences. In order to reconstruct fundamental land use/cover data for the year 1986, a central data processing and analyzing system and a regional data acquisition, processing and analyzing system have been established and are joined together as a network. After the 1986 database is established, the comparative research on the reduction in arable land, urbanization, desertification, changes in forest and grassland, and lake and wetland land use/cover change will be carried out. In addition, a transect for a key regional comparative study was selected along the Changjiang (Yangtze) River. The driving forces of these changes also will be extracted. The result of this study will be not only make a contribution to global land use/cover change research, but will also support decision making for sustainable national development.展开更多
Remote sensing and geographic information systems (GIS) technologies were used to detect land use/cover changes (LUCC) and to assess their impacts on land surface temperature (LST) in the Zhujiang Delta. Multi-tempora...Remote sensing and geographic information systems (GIS) technologies were used to detect land use/cover changes (LUCC) and to assess their impacts on land surface temperature (LST) in the Zhujiang Delta. Multi-temporal Landsat TM and Landsat ETM+ data were employed to identify patterns of LUCC as well as to quantify urban expansion and the associated decrease of vegetation cover. The thermal infrared bands of the data were used to retrieve LST. The results revealed a strong and uneven urban growth,which caused LST to raise 4.56℃in the newly urbanized part of the study area. Overall, remote sensing and GIS technologies were effective approaches for monitoring and analyzing urban growth patterns and evaluating their impacts on LST.展开更多
The surface wind speed(SWS)is affected by both large-scale circulation and land use and cover change(LUCC).In China,most studies have considered the effect of large-scale circulation rather than LUCC on SWS.In this st...The surface wind speed(SWS)is affected by both large-scale circulation and land use and cover change(LUCC).In China,most studies have considered the effect of large-scale circulation rather than LUCC on SWS.In this study,we evaluated the effects of LUCC on the SWS decrease during 1979-2015 over China using the observation minus reanalysis(OMR)method.There were two key findings:(1)Observed wind speed declined significantly at a rate of 0.0112 m/(s·a),whereas ERA-Interim,which can only capture the inter-annual variation of observed data,indicated a gentle downward trend.The effects of LUCC on SWS were distinct and caused a decrease of 0.0124 m/(s·a)in SWS;(2)Due to variations in the characteristics of land use types across different regions,the influence of LUCC on SWS also varied.The observed wind speed showed a rapid decline over cultivated land in Northwest China,as well as a decrease in China’s northeastern and eastern plain regions due to the urbanization.However,in the Tibetan Plateau,the impact of LUCC on wind speed was only slight and can thus be ignored.展开更多
Land use/cover change (LUCC) is a key aspect of global environment change, and in a sense indicates the influence of human activities on natural environment. Regional case study is the core of LUCC research. Taking th...Land use/cover change (LUCC) is a key aspect of global environment change, and in a sense indicates the influence of human activities on natural environment. Regional case study is the core of LUCC research. Taking the southern Liaoning Province, a coastal area facing the Bohai Sea and the Huanghai Sea, as an example, supported by ARCVIEW and ARC/INFO, this paper reconstructed LUCC patterns in three periods of 1954, 1976 and 2000, and analyzed their spatial-temporal changes from 1954 to 2000. On the base of these, it also studied the LUCC’s driving mechanism. The results show that the land transformation mainly occurs among cultivated land, forestland and urban and industrial land. Industrialization and urbanization in rural area are the major driving forces for cultivated land change, and the extension of the built-up area in cities is mainly the result of economic development and tertiary industry development, etc., which is at expense of cultivated land.展开更多
The NCAR Community Atmosphere Model(CAM4.0)was used to investigate the climate efects of land use/land cover change(LUCC).Two simulations,one with potential land cover without significant human intervention and the ot...The NCAR Community Atmosphere Model(CAM4.0)was used to investigate the climate efects of land use/land cover change(LUCC).Two simulations,one with potential land cover without significant human intervention and the other with current land use,were conducted.Results show that the impacts of LUCC on diurnal temperature range(DTR)are more significant than on mean surface air temperature.The global average annual DTR change due to LUCC is–0.1℃,which is three times as large as the mean temperature change.LUCC influences regional DTR as simulated by the model.In the mid-latitudes,LUCC leads to a decrease in DTR,which is mainly caused by the reduction in daily maximum temperature.However,there are some diferences in the low latitudes.The reduction in DTR in East Asia is mainly the result of the decrease in daily maximum temperature,while in India,the decrease in DTR is due to the increase in daily minimum temperature.In general,the LUCC significantly controls the DTR change through the changes in canopy evaporation and transpiration.展开更多
Validity of CA-Markov in land use and cover change simulation was investigated at the Langat Basin, Selangor, Malaysia. CA-Markov validation was performed using validation metrics, allocation disagreement, quantity di...Validity of CA-Markov in land use and cover change simulation was investigated at the Langat Basin, Selangor, Malaysia. CA-Markov validation was performed using validation metrics, allocation disagreement, quantity disagreement, and figure of merit in a three-dimensional space. The figure of merit, quantity error, and allocation error for total landscape simulation using the 1990-1997 calibration data were 5.62%, 3.53%, and 6.13%, respectively. CA-Markov showed a poor performance for land use and cover change simulation due to uncertainties in the source data, the model, and future land use and cover change processes in the study area.展开更多
This study uses DEM (Digital Elevation Model) data and remote sensing maps of the study area in 1993, 1999, and 2009 to analyze the slope gradient change of land use patterns in Qiandongnan Prefecture, Guizhou provi...This study uses DEM (Digital Elevation Model) data and remote sensing maps of the study area in 1993, 1999, and 2009 to analyze the slope gradient change of land use patterns in Qiandongnan Prefecture, Guizhou province, China. The land use data were classified into five types, forest, farmland, grassland, water and built-up, the slope gradients were divided into four grades. Indices for analyzing land use features were defined by their proportions, transformation matrixes, land use degree and changes The results showed that all land use types can be found at every gradient. Generally, with the slope degree increased, the area of forest being augmented as well, while the area of the other land use types (farmland, grassland and build-up) declined. Moreover, a mass of farmland were shifted from other land use types from o° to 25°, while a quantity of forest were transformed from the other land use types on 〉 25° from 2993 to 2009. In terms of land use degree and changes, the area of farmland and buildup land use types decreased when slope degree increased. Finally, we calculated the five landscape pattern metrics: Patch Density (PD) value, Largest Patch Index (LPI), Shannon's Diversity Index (SHDI), Area-Weighted Mean Shape Index (AWMSI) and Contagion Index (CONTAG). The results of metricsanalysis showed that PD values, SHDI values and CONTA values had a similar variation trend, that is, they decreased when slope degree increased. There was no obvious variation trend on LPI value.展开更多
Land change is a cause and consequence of global environmental change.Land use and land cover have changed considerably due to increasing human activities and climate change,which has become the core issue of major in...Land change is a cause and consequence of global environmental change.Land use and land cover have changed considerably due to increasing human activities and climate change,which has become the core issue of major international research projects.This study interprets land use and land cover status and the changes within the Koshi River Basin(KRB)using Landsat remote sensing(RS)image data,and employs logistic regression model to analyze the influence of natural and socioeconomic driving forces on major land cover changes.The results showed that the areas of built-up land,bare land and forest in KRB increased from 1990 to 2015,including the largest increases in forest and the highest growth rate in construction land.Areas of glacier,grassland,sparse vegetation,shrub land,cropland,and wetland all decreased over the study period.From the perspective of driving analysis,the role of human activities in land use and land cover change is significant than climate factors.Cropland expansion is the reclamation of cropland by farmers,mainly from early deforestation.However,labor force separation,geological disasters and drought are the main factors of cropland shrinkage.The increase of forest area in India and Nepal was attributed to the government’s forest protection policies,such as Nepal’s community forestry has achieved remarkable results.The expansion and contraction of grassland were both dominated by climatic factors.The probability of grassland expansion increases with temperature and precipitation,while the probability of grassland contraction decreases with temperature and precipitation.展开更多
With the classifi cation data covering American land-use/land-cover (LUCC) with 30 m resolu tion from the project of National Land Cover Data (NLCD), we normalize d them and made their resolution changed into 1 km ...With the classifi cation data covering American land-use/land-cover (LUCC) with 30 m resolu tion from the project of National Land Cover Data (NLCD), we normalize d them and made their resolution changed into 1 km ×1 km, created the data of American land-use grade and analyzed the spatial distribution and featur es of American LUCC as well as the influence of population and altit ude on the land-use grade in light of methods of sampling analysis a nd correlation study. Based on the analysis, we concluded that forestr y and grassland, accounting for 71.24% of the whole country, has taken the main part of American land cover, and besides, construction and arable land has occupied 19.22% of the total land, the rest of land cover types, including water area, wetland and underdeveloped land, is 9. 54% of the country's total. The developing potential of American land resources is enormous with less destroyed and disturbed ecological environment. Although, in some sense, the population and altitude influence the sp atial variation of American land-use grade respectively, the influence of spatial variation of altitude and population density on that of la nd-use grade is not significanct.展开更多
Qinghai Lake is the largest saline lake in China.The change in the lake volume is an indicator of the variation in water resources and their response to climate change on the Qinghai-Tibetan Plateau(QTP)in China.The p...Qinghai Lake is the largest saline lake in China.The change in the lake volume is an indicator of the variation in water resources and their response to climate change on the Qinghai-Tibetan Plateau(QTP)in China.The present study quantitatively evaluated the effects of climate change and land use/cover change(LUCC)on the lake volume of the Qinghai Lake in China from 1958 to 2018,which is crucial for water resources management in the Qinghai Lake Basin.To explore the effects of climate change and LUCC on the Qinghai Lake volume,we analyzed the lake level observation data and multi-period land use/land cover(LULC)data by using an improved lake volume estimation method and Integrated Valuation of Ecosystem Services and Trade-offs(InVEST)model.Our results showed that the lake level decreased at the rate of 0.08 m/a from 1958 to 2004 and increased at the rate of 0.16 m/a from 2004 to 2018.The lake volume decreased by 105.40×10^(8) m^(3) from 1958 to 2004,with the rate of 2.24×10^(8) m^(3)/a,whereas it increased by 74.02×10^(8) m^(3) from 2004 to 2018,with the rate of 4.66×10^(8) m^(3)/a.Further,the climate of the Qinghai Lake Basin changed from warm-dry to warm-humid.From 1958 to 2018,the increase in precipitation and the decrease in evaporation controlled the change of the lake volume,which were the main climatic factors affecting the lake volume change.From 1977 to 2018,the measured water yield showed an"increase-decrease-increase"fluctuation in the Qinghai Lake Basin.The effects of climate change and LUCC on the measured water yield were obviously different.From 1977 to 2018,the contribution rate of LUCC was -0.76% and that of climate change was 100.76%;the corresponding rates were 8.57% and 91.43% from 1977 to 2004,respectively,and -4.25% and 104.25% from 2004 to 2018,respectively.Quantitative analysis of the effects and contribution rates of climate change and LUCC on the Qinghai Lake volume revealed the scientific significance of climate change and LUCC,as well as their individual and combined effects in the Qinghai Lake Basin and on the QTP.This study can contribute to the water resources management and regional sustainable development of the Qinghai Lake Basin.展开更多
In recent years, the streamflow of the Laohahe Basin in China showed a dramatic decrease during the rainy season as a result of climate change and/or human activities. The objective of this work was to document signif...In recent years, the streamflow of the Laohahe Basin in China showed a dramatic decrease during the rainy season as a result of climate change and/or human activities. The objective of this work was to document significant streamflow changes caused by land use and land cover (LULC) changes and to quantify the impacts of the observed changes in Laohahe Basin. in the study area, the observed streamflow has been influenced by LULC changes, dams, and irrigation from rivers, industry, livestock and human consumption. Most importantly, the growth of population and gross domestic product (GDP) accompanied by the growth in industrial and agricultural activities, which led to LULC changes with increased residential land and cropland and decreased grassland since 2000s. Statistical methods and Variable Infiltration Capacity (VIC) hydrological model were used to estimate the effects of climate change and LULC changes on streamflow and evaportranspiration lET). First, the streamflow data of the study area were divided into three sub-periods according to the Pettitt test. The hydrological process was then simulated by VIC model from 1964 to 2009. Furthermore, we compared the simulated results based on land use scenarios in 1989, 1999 and 2007, respectively for exploring the effect of LULC changes on the spatio-temporal distribution of streamflow and ET in the Laohahe Basin. The results suggest that, accompanied with climate change, the LULC changes and human water consumption appeared to be the most likely factors contributing to the sig- nificant reduction in streamflow in the Laohahe Basin by 64% from1999 to 2009.展开更多
基金supported by the Central Government to Guide Local Technological Development(23ZYQH0298)the Science and Technology Project of Gansu Province(20JR10RA656,22JR5RA416)the Science and Technology Project of Wuwei City(WW2202YFS006).
文摘Land use and cover change(LUCC)is the most direct manifestation of the interaction between anthropological activities and the natural environment on Earth's surface,with significant impacts on the environment and social economy.Rapid economic development and climate change have resulted in significant changes in land use and cover.The Shiyang River Basin,located in the eastern part of the Hexi Corridor in China,has undergone significant climate change and LUCC over the past few decades.In this study,we used the random forest classification to obtain the land use and cover datasets of the Shiyang River Basin in 1991,1995,2000,2005,2010,2015,and 2020 based on Landsat images.We validated the land use and cover data in 2015 from the random forest classification results(this study),the high-resolution dataset of annual global land cover from 2000 to 2015(AGLC-2000-2015),the global 30 m land cover classification with a fine classification system(GLC_FCS30),and the first Landsat-derived annual China Land Cover Dataset(CLCD)against ground-truth classification results to evaluate the accuracy of the classification results in this study.Furthermore,we explored and compared the spatiotemporal patterns of LUCC in the upper,middle,and lower reaches of the Shiyang River Basin over the past 30 years,and employed the random forest importance ranking method to analyze the influencing factors of LUCC based on natural(evapotranspiration,precipitation,temperature,and surface soil moisture)and anthropogenic(nighttime light,gross domestic product(GDP),and population)factors.The results indicated that the random forest classification results for land use and cover in the Shiyang River Basin in 2015 outperformed the AGLC-2000-2015,GLC_FCS30,and CLCD datasets in both overall and partial validations.Moreover,the classification results in this study exhibited a high level of agreement with the ground truth features.From 1991 to 2020,the area of bare land exhibited a decreasing trend,with changes primarily occurring in the middle and lower reaches of the basin.The area of grassland initially decreased and then increased,with changes occurring mainly in the upper and middle reaches of the basin.In contrast,the area of cropland initially increased and then decreased,with changes occurring in the middle and lower reaches.The LUCC was influenced by both natural and anthropogenic factors.Climatic factors and population contributed significantly to LUCC,and the importance values of evapotranspiration,precipitation,temperature,and population were 22.12%,32.41%,21.89%,and 19.65%,respectively.Moreover,policy interventions also played an important role.Land use and cover in the Shiyang River Basin exhibited fluctuating changes over the past 30 years,with the ecological environment improving in the last 10 years.This suggests that governance efforts in the study area have had some effects,and the government can continue to move in this direction in the future.The findings can provide crucial insights for related research and regional sustainable development in the Shiyang River Basin and other similar arid and semi-arid areas.
文摘The Himalayan region has been experiencing stark impacts of climate change,demographic and livelihood pattern changes.The analysis of land use and land cover(LULC)change provides insights into the shifts in spatial and temporal patterns of landscape.These changes are the combined effects of anthropogenic and natural/climatic factors.The present study attempts to monitor and comprehend the main drivers behind LULC changes(1999-2021)in the Himalayan region of Pithoragarh district,Uttarakhand.Pithoragarh district is a border district,remotely located in the north-east region of Uttarakhand,India.The study draws upon primary and secondary data sources.A total of 400 household surveys and five group discussions from 38 villages were conducted randomly to understand the climate perception of the local community and the drivers of change.Satellite imagery,CRU(Climatic Research Unit)climate data and climate perception data from the field have been used to comprehensively comprehend,analyze,and discuss the trends and reasons for LULC change.GIS and remote sensing techniques were used to construct LULC maps.This multifaceted approach ensures comprehensive and corroborated information.Five classes were identified and formed viz-cultivation,barren,settlement,snow,and vegetation.Results show that vegetation and builtup have increased whereas cultivation,barren land,and snow cover have decreased.The study further aims to elucidate the causes behind LULC changes in the spatially heterogeneous region,distinguishing between those attributed to human activities,climate shifts,and the interconnected impacts of both.The study provides a comprehensive picture of the study area and delivers a targeted understanding of local drivers and their potential remedies by offering a foundation for formulating sustainable adaptation policies in the region.
基金partly funded by the National Key Research and Development Program of China(NK2023190801)the National Foreign Experts Program of China(G2023041024L)the Key Scientific Research Program of Shaanxi Provincial Education Department,China(21JT028)。
文摘Understanding the trajectories and driving mechanisms behind land use/land cover(LULC)changes is essential for effective watershed planning and management.This study quantified the net change,exchange,total change,and transfer rate of LULC in the Jinghe River Basin(JRB),China using LULC data from 2000 to 2020.Through trajectory analysis,knowledge maps,chord diagrams,and standard deviation ellipse method,we examined the spatiotemporal characteristics of LULC changes.We further established an index system encompassing natural factors(digital elevation model(DEM),slope,aspect,and curvature),socio-economic factors(gross domestic product(GDP)and population),and accessibility factors(distance from railways,distance from highways,distance from water,and distance from residents)to investigate the driving mechanisms of LULC changes using factor detector and interaction detector in the geographical detector(Geodetector).The key findings indicate that from 2000 to 2020,the JRB experienced significant LULC changes,particularly for farmland,forest,and grassland.During the study period,LULC change trajectories were categorized into stable,early-stage,late-stage,repeated,and continuous change types.Besides the stable change type,the late-stage change type predominated the LULC change trajectories,comprising 83.31% of the total change area.The period 2010-2020 witnessed more active LULC changes compared to the period 2000-2010.The LULC changes exhibited a discrete spatial expansion trend during 2000-2020,predominantly extending from southeast to northwest of the JRB.Influential driving factors on LULC changes included slope,GDP,and distance from highways.The interaction detection results imply either bilinear or nonlinear enhancement for any two driving factors impacting the LULC changes from 2000 to 2020.This comprehensive understanding of the spatiotemporal characteristics and driving mechanisms of LULC changes offers valuable insights for the planning and sustainable management of LULC in the JRB.
基金the University Grants Commission,New Delhi,India,for providing financial support in the form of the Junior Research Fellowship。
文摘Rapid urbanization creates complexity,results in dynamic changes in land and environment,and influences the land surface temperature(LST)in fast-developing cities.In this study,we examined the impact of land use/land cover(LULC)changes on LST and determined the intensity of urban heat island(UHI)in New Town Kolkata(a smart city),eastern India,from 1991 to 2021 at 10-a intervals using various series of Landsat multi-spectral and thermal bands.This study used the maximum likelihood algorithm for image classification and other methods like the correlation analysis and hotspot analysis(Getis–Ord Gi^(*) method)to examine the impact of LULC changes on urban thermal environment.This study noticed that the area percentage of built-up land increased rapidly from 21.91%to 45.63%during 1991–2021,with a maximum positive change in built-up land and a maximum negative change in sparse vegetation.The mean temperature significantly increased during the study period(1991–2021),from 16.31℃to 22.48℃in winter,29.18℃to 34.61℃in summer,and 19.18℃to 27.11℃in autumn.The result showed that impervious surfaces contribute to higher LST,whereas vegetation helps decrease it.Poor ecological status has been found in built-up land,and excellent ecological status has been found in vegetation and water body.The hot spot and cold spot areas shifted their locations every decade due to random LULC changes.Even after New Town Kolkata became a smart city,high LST has been observed.Overall,this study indicated that urbanization and changes in LULC patterns can influence the urban thermal environment,and appropriate planning is needed to reduce LST.This study can help policy-makers create sustainable smart cities.
文摘Information on the dynamics of savannah is important to a country's plan to overcome the problems of uncontrolled development and environmental hazards. Taking the reserve partielle de Dosso, Niger as the case study area, this paper analyzed the long-term land use land cover change from 2002 to 2022. Satellite images were processed by using Google Earth Engine (GEE). Therefore, four major land cover classes were identified based on spectral characteristics of Land sat, namely, built-up, vegetation, cropland, bare land and water. The result revealed that barren and built-up areas increased at the expense of vegetation and water. From the four major land use land cover the large area is covered by vegetation which comprises about 192963.5 hectares followed by cropland and water consisting of 32506.43 and 1596.4 hectares respectively. The built-up area gained substantial area (most) during the study period. The reduction in some of the land cover/uses underlines the dangerous trend of the pressure poised by population growth and the changing functionality. Land cover change is influenced by a variety of societal factors operating on several spatial and temporal levels. The area estimates and spatial distributions of the LULC classes produced from the current study will assist local authorities, managers, and other stakeholders in decision-making and planning regarding forest land cover and uses.
基金supported by the National Natural Science Foundation of China(41671520)the Harbin Youth Reserve Talent Program,China(2016RAQXJ058)。
文摘Understanding the effects of land use/cover change(LUCC) on regional climate is critical for achieving land use system sustainability and global climate change mitigation. However, the quantitative analysis of the contribution of LUCC to the changes of climatic factors, such as precipitation & temperature(P&T), is lacking. In this study, we combined statistical methods and the gravity center model simulation to quantify the effects of long-term LUCC on P&T in the Songnen Plain(SNP) of Northeast China from 1980–2018. The results showed the spatiotemporal variability of LUCC. For example, paddy field had the largest increase(15 166.43 km2) in the SNP, followed by dry land, while wetland had the largest decrease(19 977.13 km;) due to the excessive agricultural utilization and development. Annual average precipitation decreased at a rate of –9.89 mm per decade, and the warming trends were statistically significant with an increasing rate of 0.256°C per decade in this region since 1980. The model simulation revealed that paddy field, forestland, and wetland had positive effects on precipitation, which caused their gravity centers to migrate towards the same direction accompanied by the center of precipitation gravity, while different responses were seen for building land, dry land and unused land. These results indicated that forestland had the largest influence on the increase of precipitation compared with the other land use types.The responses in promoting the temperature increase differed significantly, being the highest in building land, and the lowest in forestland. In general, the analysis of regional-scale LUCC showed a significant reduction of wetland, and the increases in building land and cropland contributed to a continuous drying and rapid warming in the SNP.
文摘This paper carries out quantitative analysis on the land use/cover (LU/C) change of 13anjin Binhai New Area in recent 10 years through using land use transition matrix from the three-stage LU/C classification maps of 2000, 2005 and 2010 drafted by means of the National Land Classification System of China based on Landsat TM satellite remote sensing image and the Tianjin Binhai New Area 1:50 000 relief maps. On this basis, the impact of such driving factors as the economy and population on LU/C is further analyzed. The results show that the area of the building land in Binhai New Area has increased significantly over the ten years, and the greenland, wetland, and shoals of high ecological value have been dramatically transformed into the building land and unused land for the development and construction, and the change is more significant in the later five years.
文摘The objective of this work is to produce statistics that are going to show changes occurred in Brazil's ecosystems and these statistics are going to join the SEEA (Environmental-Economic Accounts System). It is based by a SEEA's methodology, diffused by UN (United Nations), which aims an approach between economic and environmental statistics, producing international comparability and conceptual uniformity to evaluate change process in land cover and land use that occurs in several countries. It is necessary to verifying the suitability of methodological procedures to Brazilian reality and the access to all information and files needed. The first step was analysing MODIS (Moderate Resolution Imaging Spectroradiometer) as orbital instrument on the purposed classification method. The choice of this sensor was made because of the product's quality and its capacity to generate images of a large area, though the challenge is to identify accurate Land usage's categories in images with a spatial resolution of approximately 250 m. After the final classification, the next step is to make a quantification and comparison of data from these different years using a 1 km2 grids, as proposed in an already used methodology by the European Environment Agency. This procedure will allow evaluate and identify the process of changing in each grid of the land cover and land use, and provide historical series of the chosen years.
文摘Land cover is an impression of natural cover on surface of earth such as bare soil, river, grass etc. and utilization of these natural covers for various human needs and purposes by mankind is defined as land use. Land cover identification, delineation and mapping is important for planning activities, resource management and global monitoring studies while baseline mapping and subsequent monitoring is done by application of land use to get timely information about quantity of land that has been used. The present study has been carried out in Dhund river watershed of Jaipur, Rajasthan which covers an area of about 1828 sq∙km. The minimum and maximum elevation of the area is found to be 214 m and 603 m respectively. Land use and land cover changes of three decades from 1991 to 2021 have been interpreted by using remotes sensing and GIS techniques. ArcGIS software (Arc map 10.2), SOI topographic map, Cartosat-1 DEM and satellite data of Landsat 5 and Landsat 8 have been used for interpretation of eleven classes. The study shows an increase in cultivated land, settlement, waterbody, open forest, plantation and mining due to urbanization because of increasing demands of food, shelter and water while a decrease in dense forest, river, open scrub, wasteland and uncultivated land has also been marked due to destruction of aforementioned by anthropogenic activities such as industrialization resulting in environmental degradation that leads to air, soil and water pollution.
文摘Land use/cover change, which in China is characterized by urbanization resulting in a decrease in arable land in the east along with a large area of grassland being cultivated in the west, has been accelerated by rapid economic development in the last years. All of the above changes will affect sustainable development in the next century. The Chinese Academy of Sciences is conducting a study of land use/cover change over the last ten years based on the integration of remote sensing and GIS technology to establish a multitemporal database covering all of China. Fundamental data for land use/cover for the year 1996 has already been developed by the Chinese Academy of Sciences. In order to reconstruct fundamental land use/cover data for the year 1986, a central data processing and analyzing system and a regional data acquisition, processing and analyzing system have been established and are joined together as a network. After the 1986 database is established, the comparative research on the reduction in arable land, urbanization, desertification, changes in forest and grassland, and lake and wetland land use/cover change will be carried out. In addition, a transect for a key regional comparative study was selected along the Changjiang (Yangtze) River. The driving forces of these changes also will be extracted. The result of this study will be not only make a contribution to global land use/cover change research, but will also support decision making for sustainable national development.
基金Project supported by the Science and Technology Project Foundation of Guangzhou (No. 2005Z3-D0551)the Science and Technology Project Foundation of Guangzhou Education Bureau (No. 62026)
文摘Remote sensing and geographic information systems (GIS) technologies were used to detect land use/cover changes (LUCC) and to assess their impacts on land surface temperature (LST) in the Zhujiang Delta. Multi-temporal Landsat TM and Landsat ETM+ data were employed to identify patterns of LUCC as well as to quantify urban expansion and the associated decrease of vegetation cover. The thermal infrared bands of the data were used to retrieve LST. The results revealed a strong and uneven urban growth,which caused LST to raise 4.56℃in the newly urbanized part of the study area. Overall, remote sensing and GIS technologies were effective approaches for monitoring and analyzing urban growth patterns and evaluating their impacts on LST.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA19030204)the CAS"Light of West China"Program(2015-XBQNB-17)
文摘The surface wind speed(SWS)is affected by both large-scale circulation and land use and cover change(LUCC).In China,most studies have considered the effect of large-scale circulation rather than LUCC on SWS.In this study,we evaluated the effects of LUCC on the SWS decrease during 1979-2015 over China using the observation minus reanalysis(OMR)method.There were two key findings:(1)Observed wind speed declined significantly at a rate of 0.0112 m/(s·a),whereas ERA-Interim,which can only capture the inter-annual variation of observed data,indicated a gentle downward trend.The effects of LUCC on SWS were distinct and caused a decrease of 0.0124 m/(s·a)in SWS;(2)Due to variations in the characteristics of land use types across different regions,the influence of LUCC on SWS also varied.The observed wind speed showed a rapid decline over cultivated land in Northwest China,as well as a decrease in China’s northeastern and eastern plain regions due to the urbanization.However,in the Tibetan Plateau,the impact of LUCC on wind speed was only slight and can thus be ignored.
基金Under theauspices of Chinese Academy of Sciences(No .KZCX2-SW-320 )
文摘Land use/cover change (LUCC) is a key aspect of global environment change, and in a sense indicates the influence of human activities on natural environment. Regional case study is the core of LUCC research. Taking the southern Liaoning Province, a coastal area facing the Bohai Sea and the Huanghai Sea, as an example, supported by ARCVIEW and ARC/INFO, this paper reconstructed LUCC patterns in three periods of 1954, 1976 and 2000, and analyzed their spatial-temporal changes from 1954 to 2000. On the base of these, it also studied the LUCC’s driving mechanism. The results show that the land transformation mainly occurs among cultivated land, forestland and urban and industrial land. Industrialization and urbanization in rural area are the major driving forces for cultivated land change, and the extension of the built-up area in cities is mainly the result of economic development and tertiary industry development, etc., which is at expense of cultivated land.
基金jointly supported by the National Basic Research Program of China(No.2011CB952000)project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘The NCAR Community Atmosphere Model(CAM4.0)was used to investigate the climate efects of land use/land cover change(LUCC).Two simulations,one with potential land cover without significant human intervention and the other with current land use,were conducted.Results show that the impacts of LUCC on diurnal temperature range(DTR)are more significant than on mean surface air temperature.The global average annual DTR change due to LUCC is–0.1℃,which is three times as large as the mean temperature change.LUCC influences regional DTR as simulated by the model.In the mid-latitudes,LUCC leads to a decrease in DTR,which is mainly caused by the reduction in daily maximum temperature.However,there are some diferences in the low latitudes.The reduction in DTR in East Asia is mainly the result of the decrease in daily maximum temperature,while in India,the decrease in DTR is due to the increase in daily minimum temperature.In general,the LUCC significantly controls the DTR change through the changes in canopy evaporation and transpiration.
文摘Validity of CA-Markov in land use and cover change simulation was investigated at the Langat Basin, Selangor, Malaysia. CA-Markov validation was performed using validation metrics, allocation disagreement, quantity disagreement, and figure of merit in a three-dimensional space. The figure of merit, quantity error, and allocation error for total landscape simulation using the 1990-1997 calibration data were 5.62%, 3.53%, and 6.13%, respectively. CA-Markov showed a poor performance for land use and cover change simulation due to uncertainties in the source data, the model, and future land use and cover change processes in the study area.
基金supported by the National Natural Science Foundation of China (Grant No. 31370480)111 Project (B08044)Minzu University of China (MUC98507-08)
文摘This study uses DEM (Digital Elevation Model) data and remote sensing maps of the study area in 1993, 1999, and 2009 to analyze the slope gradient change of land use patterns in Qiandongnan Prefecture, Guizhou province, China. The land use data were classified into five types, forest, farmland, grassland, water and built-up, the slope gradients were divided into four grades. Indices for analyzing land use features were defined by their proportions, transformation matrixes, land use degree and changes The results showed that all land use types can be found at every gradient. Generally, with the slope degree increased, the area of forest being augmented as well, while the area of the other land use types (farmland, grassland and build-up) declined. Moreover, a mass of farmland were shifted from other land use types from o° to 25°, while a quantity of forest were transformed from the other land use types on 〉 25° from 2993 to 2009. In terms of land use degree and changes, the area of farmland and buildup land use types decreased when slope degree increased. Finally, we calculated the five landscape pattern metrics: Patch Density (PD) value, Largest Patch Index (LPI), Shannon's Diversity Index (SHDI), Area-Weighted Mean Shape Index (AWMSI) and Contagion Index (CONTAG). The results of metricsanalysis showed that PD values, SHDI values and CONTA values had a similar variation trend, that is, they decreased when slope degree increased. There was no obvious variation trend on LPI value.
基金financially supported by the National Natural Science Foundation of China(Grant No.41761144081)Second Tibetan Plateau Scientific Expedition and Research(Grant No.2019QZKK0603)Strategic Priority Research Program of the ChineseAcademyofSciences(GrantNo.XDA20040201)。
文摘Land change is a cause and consequence of global environmental change.Land use and land cover have changed considerably due to increasing human activities and climate change,which has become the core issue of major international research projects.This study interprets land use and land cover status and the changes within the Koshi River Basin(KRB)using Landsat remote sensing(RS)image data,and employs logistic regression model to analyze the influence of natural and socioeconomic driving forces on major land cover changes.The results showed that the areas of built-up land,bare land and forest in KRB increased from 1990 to 2015,including the largest increases in forest and the highest growth rate in construction land.Areas of glacier,grassland,sparse vegetation,shrub land,cropland,and wetland all decreased over the study period.From the perspective of driving analysis,the role of human activities in land use and land cover change is significant than climate factors.Cropland expansion is the reclamation of cropland by farmers,mainly from early deforestation.However,labor force separation,geological disasters and drought are the main factors of cropland shrinkage.The increase of forest area in India and Nepal was attributed to the government’s forest protection policies,such as Nepal’s community forestry has achieved remarkable results.The expansion and contraction of grassland were both dominated by climatic factors.The probability of grassland expansion increases with temperature and precipitation,while the probability of grassland contraction decreases with temperature and precipitation.
基金National Natural Science Foundation of China, No. 90202002.
文摘With the classifi cation data covering American land-use/land-cover (LUCC) with 30 m resolu tion from the project of National Land Cover Data (NLCD), we normalize d them and made their resolution changed into 1 km ×1 km, created the data of American land-use grade and analyzed the spatial distribution and featur es of American LUCC as well as the influence of population and altit ude on the land-use grade in light of methods of sampling analysis a nd correlation study. Based on the analysis, we concluded that forestr y and grassland, accounting for 71.24% of the whole country, has taken the main part of American land cover, and besides, construction and arable land has occupied 19.22% of the total land, the rest of land cover types, including water area, wetland and underdeveloped land, is 9. 54% of the country's total. The developing potential of American land resources is enormous with less destroyed and disturbed ecological environment. Although, in some sense, the population and altitude influence the sp atial variation of American land-use grade respectively, the influence of spatial variation of altitude and population density on that of la nd-use grade is not significanct.
基金funded by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20100101)the National Key Research and Development Program of China(2019YFC0507404)the Gansu Province Science Foundation for Youth,China(20JR5RA543).
文摘Qinghai Lake is the largest saline lake in China.The change in the lake volume is an indicator of the variation in water resources and their response to climate change on the Qinghai-Tibetan Plateau(QTP)in China.The present study quantitatively evaluated the effects of climate change and land use/cover change(LUCC)on the lake volume of the Qinghai Lake in China from 1958 to 2018,which is crucial for water resources management in the Qinghai Lake Basin.To explore the effects of climate change and LUCC on the Qinghai Lake volume,we analyzed the lake level observation data and multi-period land use/land cover(LULC)data by using an improved lake volume estimation method and Integrated Valuation of Ecosystem Services and Trade-offs(InVEST)model.Our results showed that the lake level decreased at the rate of 0.08 m/a from 1958 to 2004 and increased at the rate of 0.16 m/a from 2004 to 2018.The lake volume decreased by 105.40×10^(8) m^(3) from 1958 to 2004,with the rate of 2.24×10^(8) m^(3)/a,whereas it increased by 74.02×10^(8) m^(3) from 2004 to 2018,with the rate of 4.66×10^(8) m^(3)/a.Further,the climate of the Qinghai Lake Basin changed from warm-dry to warm-humid.From 1958 to 2018,the increase in precipitation and the decrease in evaporation controlled the change of the lake volume,which were the main climatic factors affecting the lake volume change.From 1977 to 2018,the measured water yield showed an"increase-decrease-increase"fluctuation in the Qinghai Lake Basin.The effects of climate change and LUCC on the measured water yield were obviously different.From 1977 to 2018,the contribution rate of LUCC was -0.76% and that of climate change was 100.76%;the corresponding rates were 8.57% and 91.43% from 1977 to 2004,respectively,and -4.25% and 104.25% from 2004 to 2018,respectively.Quantitative analysis of the effects and contribution rates of climate change and LUCC on the Qinghai Lake volume revealed the scientific significance of climate change and LUCC,as well as their individual and combined effects in the Qinghai Lake Basin and on the QTP.This study can contribute to the water resources management and regional sustainable development of the Qinghai Lake Basin.
基金financed by the National Natural Science Foundation of China (41201031)the Special Basic Research Fund for Methodology in Hydrology of Ministry of Sciences and Technology, China (2011IM011000)+2 种基金the Innovative Research Team Project of Basic Research Funds for National University at State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering (2009585412)the 111 Project of Ministry of Education and State Administration of Foreign Experts Affairs, China (B08048)the National Key Technology R&D Program by Ministry of Sciences and Technology, China (2013BAC10B02)
文摘In recent years, the streamflow of the Laohahe Basin in China showed a dramatic decrease during the rainy season as a result of climate change and/or human activities. The objective of this work was to document significant streamflow changes caused by land use and land cover (LULC) changes and to quantify the impacts of the observed changes in Laohahe Basin. in the study area, the observed streamflow has been influenced by LULC changes, dams, and irrigation from rivers, industry, livestock and human consumption. Most importantly, the growth of population and gross domestic product (GDP) accompanied by the growth in industrial and agricultural activities, which led to LULC changes with increased residential land and cropland and decreased grassland since 2000s. Statistical methods and Variable Infiltration Capacity (VIC) hydrological model were used to estimate the effects of climate change and LULC changes on streamflow and evaportranspiration lET). First, the streamflow data of the study area were divided into three sub-periods according to the Pettitt test. The hydrological process was then simulated by VIC model from 1964 to 2009. Furthermore, we compared the simulated results based on land use scenarios in 1989, 1999 and 2007, respectively for exploring the effect of LULC changes on the spatio-temporal distribution of streamflow and ET in the Laohahe Basin. The results suggest that, accompanied with climate change, the LULC changes and human water consumption appeared to be the most likely factors contributing to the sig- nificant reduction in streamflow in the Laohahe Basin by 64% from1999 to 2009.