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In the process of studying the spatiotemporal cause mechanism of urban heat island (UHI) effects, the classification method used will directly affect the robustness of urban surface heat classification. Applying five commonly used standard classification methods, we divided Beijing's urban surface temperatures in the summer of 2020 into five levels. We then compared the reliability of the five classification methods in resolving 12-period data and the seasonal average temperature in UHI patches, based on two indicators: UHI area and UHI intensity. The actual land-use composition of the UHI patches obtained with traditional methods was applied to confirm our results. The mean-standard deviation method and natural breaks (Jenks) method were more robust with regard to UHI classification and 12-period data reliability. For the UHI area index, the mean-standard deviation method produced the smallest total area of UHI patches for summer days and nights. For the UHI intensity index, the quantile method, mean-standard deviation method, and natural breaks (Jenks) method were associated with smaller errors. Considering the composition of land-use types in UHI patches, the mean-standard deviation method, and natural breaks (Jenks) method were more rigorous. Thus, our research results provide guidance for method selection when classifying UHI.

Annual land use land cover (LULC) change information at medium spatial resolution (i.e. at 30 m) is required in numerous subjects, such as biophysical modelling, land management and global change studies. Annual LULC information, however, is usually not available at continental or national scale due to reasons such as insufficient remote sensing data coverage or lack of computational capabilities. Here we integrate high temporal resolution and coarse spatial resolution satellite images (i.e., Moderate Resolution Imaging Spectroradiometer (MODIS) and Global Inventory Modelling and Mapping Studies (GIMMS) normalized difference vegetation index (NDVI)) with high spatial resolution datasets (China’s Land-Use/cover Datasets (CLUDs) derived from 30-meter Landsat TM/ETM+/OLI) to generate reliable annual nominal 30 m LULC maps for the whole of China between 1980 and 2015. We also test the performance of a statistical based change detection algorithm (Breaks for Additive Seasonal and Trend), originally designed for tracking forest change, in classifying all-type LULC change. As a result, a nominal 30 m annual land use/land cover datasets (CLUD-A) from 1980 to 2015 was developed for the whole China. The mapping results were assessed with a change sample dataset, a regional annual validation sample set and a three-year China sample set. Of the detected change years, 75.61% matched the exact time of conversion within ±1 year. Annual mapping results provided a detail process of urbanization, deforestation, afforestation, water and cropland dynamics over the past 36 years. The consistent characterization of land change dynamics for China can be further used in scientific research and to support land management for policy-makers.

Urban parks have been proven to cool the surrounding environment, and can thus mitigate the urban heat island to an extent by forming a park cooling island. However, a comprehensive understanding of the mechanism of park cooling islands is still required. Therefore, we studied 32 urban parks in Jinan, China and proposed absolute and relative indicators to depict the detailed features of the park cooling island. High-spatial-resolution GF-2 images were used to obtain the land cover of parks, and Landsat 8 TIR images were used to examine the thermal environment by applying buffer analysis. Linear statistical models were developed to explore the relationships between park characteristics and the park cooling island. The results showed that the average land surface temperature (LST) of urban parks was approximately 3.6 °C lower than that of the study area, with the largest temperature difference of 7.84 °C occurring during summer daytime, while the average park cooling area was approximately 120.68 ha. The park cooling island could be classified into four categories—regular, declined, increased, and others—based on the changing features of the surrounding LSTs. Park area (PA), park perimeter (PP), water area proportion (WAP), and park shape index (PSI) were significantly negatively correlated with the park LST. We also found that WAP, PP, and greenness (characterized by the normalized difference vegetation index (NDVI)) were three important factors that determined the park cooling island. However, the relationship between PA and the park cooling island was complex, as the results indicated that only parks larger than a threshold size (20 ha in our study) would provide a larger cooling effect with the increase in park size. In this case, increasing the NDVI of the parks by planting more vegetation would be a more sustainable and effective solution to form a stronger park cooling island.

Fine-scale population gridded datasets are of great significance in emergency response, resource allocation, and traffic planning. Many studies have developed fine-scale population spatialization m...

Urban parks have been considered as an effective measure to mitigate the urban heat island (UHI) effects. Many studies have investigated the impacts of shape, size and interior components on the cold island effect (CIE) of parks, while little attention has been given to the impact of neighboring buildings. Thus, taking twenty-two parks in Beijing as samples, this study investigated the impacts of the neighboring building on the CIE of central parks. The results showed that the average land surface temperature (LST) of parks are 30.98 &deg, C in summer and &minus, 1.10 &deg, C in winter. Parks have a strong CIE in summer, and average cold island footprint (CIF) and LST difference are 0.15 km2 and 2.01 &deg, C higher than that in winter. The components of the building in the CIF of parks are dominated by middle-rise building (MRB), followed by low-rise building (LRB), and high-rise building (HRB) is the least dominant. The percentage of landscape (PLAND) and landscape shape index (LSI) of MRB, and perimeter area fractal dimension (PAFRAC) of LRB are significantly related to CIF in summer and winter. This study could extend scientific understanding of the impacts of neighboring buildings on the CIE of central parks, and could guide urban planners in mitigating the UHI effects through the rational allocation of buildings.

Many catchments in northern Algeria, including the coastal Mitidja Basin in the north central part of the country have been negatively affected by the deterioration of water quality in recent years. This study aims to discover the relationship between land use change and its impact on water quality in the coastal Mitidja river basin. Based on the data of land use and water quality in 2000, 2010 and 2017, the relationship between land use change and surface water quality index in the Mitidja Watershed was discussed through GIS and statistical analysis. The results show that the physical and chemical properties of the Mitidja river basin have obvious spatial heterogeneity. The water quality of upstream was better than that of downstream. There was a significant spatial relationship between the eight water quality indicators and three land use types, including urban residential land, agricultural land and vegetation. In most cases, settlements and agricultural land are the dominant factors leading to river pollution, and higher vegetation coverage helps to improve water quality. The regression model revealed that percentage of urban settlement area was a predictor for NH4-N, BOD5, COD, SS, PO4-P, DO and pH, while vegetation was a predictor for NO3-N. The analysis also showed that during this period, urban settlement areas increased sharply, which has a significant impact on water quality variables. Agricultural land only had a significant positive correlation with PO4-P. The results provide an effective way to evaluate river water quality, control water pollution and land use management by landscape pattern.

Urban parks can effectively mitigate the urban heat island (UHI) effect. Many studies have investigated the relationship between the shape, size, interior components and cooling effect of the park, little attention have been given to explore the relationship between land surface temperature (LST) of central park and buildings in the neighboring areas. This study has explored the effect of the neighboring building on LST of central park, taking Beijing as the study area. The results showed that the cold island footprint of the park in summer was larger than that in winter (with an average area of 0.15 km2 larger). The components of building in cold island footprint of the park were dominated by middle-rese building (MRB). LSI of MRB and AREA_SD of LMB were identified as the key explanatory variables in summer and winter, respectively, which could explained 16.8% and 13.9% of the variance in the park’s LST. This study could extend scientific understanding of the effect of building on park’s LST, and could provide guidance to urban planners on how to mitigate the UHI effects through the rational allocation of buildings.

Urban Heat Island (UHI), a phenomenon characterized by significantly higher air and land surface temperatures (LSTs) in urban areas than in suburban areas, results in land use change from non-urban to urban land and is accompanied by increases in anthropogenic heat release. A variety of land use contribution indexes have been proposed to quantitatively calculate the impact of land use types on UHI. However, these indexes can only show the impact of specific land use types on UHI. In fact, the area and the intensity (which also can be considered as the average temperature) of land use change jointly determine the regional UHI. The purpose of this paper is to develop an algorithm to quantitatively reveal the influence of the area and the intensity of land use change on regional UHI. MODIS LST products and 1:1,000,000 land use data sets were used to quantitatively calculate the seasonal and interannual contributions of land use change on regional UHI between 2005 and 2018 in China. These results have theoretical and practical significance for further understanding the formation mechanism of urban thermal environment and its mitigation measures.

Tourism development activities affect the structure and functions of ecosystems directly triggering changes in the thermal environment of tourism destinations and raising a need for sustainable development of the tourism industry. Using the 2005–2015 moderate resolution imaging spectroradiometer (MODIS) data on the land surface temperature combined with the land use data, the urban thermal environment contribution index (CI) of prefecture-level cities and ecosystem types corresponding to the study area in Sichuan-Chongqing region were quantitatively calculated under various seasonal and diurnal conditions in terms of the scales of administrative divisions and ecosystem types. The characteristics of the roles played by different cities and ecosystem types to contribute to the thermal environment of the metropolitan region were summarized, and the differences and changes in the corresponding contribution intensity of various ecosystem types were measured. The results indicate the following: (1) Different cities play different roles as the sources and sinks with respect to the thermal environment in the daytime and nighttime. Based on the diurnal differences of the contribution indices, cities can be divided into three types: the day-night heat source type, the day-sink and night-source type, and the day-night heat sink type. (2) The farmland and the grassland ecosystems are the most important source and sink landscapes in the thermal environment of the Sichuan-Chongqing Region, respectively. (3) The region is affected by the spatial arrangement of the internal ecosystems and its own development conditions, and, consequently, there are significant temporal-spatial variations and role transitions between heat source and heat sink regarding the contribution of different ecosystem types to the thermal environment of individual cities. It is important to scientifically regulate the thermal environment effect on tourism destinations and maintain the comfort and sustainable development through identifying the source and sink ecosystems of the thermal environment, controlling the quantity and spatial arrangement of the heat source ecosystems, and fully enabling the cooling effect of the heat sink ecosystems.

Air quality in China is characterized by significant spatial and temporal differences, which are directly related to local meteorological conditions. This study used air quality monitoring data, namely, the air pollution index (API) and air quality index (AQI) between 2005 and 2018, together with meteorological data and identified key meteorological factors that affected the spatial and temporal variation of air quality using a random forest algorithm. The spatial and temporal differences in the threshold values of different meteorological factors affecting the concentrations of PM2.5, PM10, SO2, CO, NO2, and O3 were identified. The AQI has the advantages of facilitating higher index values than the API. The air quality showed an improvement from 2005 to 2018. Wind direction and precipitation were the most important meteorological factors affecting the air quality in northern and southern China, respectively, which to some extent reflected the causes and degradation mechanisms of air pollution in the two regions. There were significant spatial and temporal differences in the effects of meteorological factors on the concentrations of different pollutants. The influence of atmospheric pressure on pollutant concentration differed between the east and west. Precipitation and relative humidity in most cities had significant impacts on PM2.5 and PM10. The influence of relative humidity was most significant for SO2 and it also had a great influence on O3, while wind speed had a great influence on NO2. The results of the study confirm the meteorological sensitivity of air quality and provide support for the implementation of regional air pollution prevention and control initiatives.

Rapeseed is one of the major oil crops in China and it is very sensitive to climate change. The Yangtze River Basin is the main rapeseed production area in China. Therefore, a better understanding of the impact of climate change on rapeseed production in the basin is of both scientific and practical importance to Chinese oil industry and food security. In this study, based on climate data from 5 General Circulation Models (GCMs) with 4 representative concentration pathways (RCPs) in 2011–2040 (2020s), 2041–2070 (2050s) and 2071–2100 (2080s), we assessed the changes in rapeseed production potential between the baseline climatology of 1981–2010 and the future climatology of the 2020s, 2050s, and 2080s, respectively. The key modelling tool – the AEZ model – was updated and validated based on the observation records of 10 representative sites in the basin. Our simulations revealed that: (1) the uncertainty of the impact of climate change on rapeseed production increases with time; (2) in the middle of this century (2050s), total rapeseed production would increase significantly; (3) the average production potential increase in the 2050s for the upper, middle and lower reaches of the Yangtze River Basin is 0.939, 1.639 and 0.339 million tons respectively; (4) areas showing most significant increases in production include southern Shaanxi, central and eastern Hubei, northern Hunan, central Anhui and eastern Jiangsu.

Investigating the relationship between land surface temperature (LST) and other satellite-derived land surface parameters is beneficial to exploring adaptation and mitigation strategies for urban t...

The maintenance and improvement of ecosystem services on the Tibet Plateau are critical for national ecological security in China and are core objectives of ecological conservation in this region. In this paper, ecosystem service benefits of the Tibet Ecological Conservation Project were comprehensively assessed by estimating and mapping the spatiotemporal variation patterns of critical ecosystem services on the Tibet Plateau from 2000 to 2015. Furthermore, we linked the benefit assessment to the sustainable spatial planning of future ecological conservation strategies. Comparing the 8 years before and after the project, the water retention and carbon sink services of the forest, grassland and wetland ecosystems were slightly increased after the project, and the ecosystem sand fixation service has been steadily enhanced. The increasing forage supply service of grassland significantly reduced the grassland carrying pressure and eased the conflict between grassland and livestock. However, enhanced rainfall erosivity occurred due to increased rainfall, and root-layer soils could not recover in a short period of time, both factors have led to a decline in soil conservation service. The warm and humid climate is beneficial for the restoration of ecosystems on the Tibet Plateau, and the implementation of the Tibet Ecological Conservation Project has had a positive effect on the local improvement of ecosystem services. A new spatial planning strategy for ecological conservation was introduced and aims to establish a comprehensive, nationwide system to protect important natural ecosystems and wildlife, and to promote the sustainable use of natural resources.

An understanding of the spatio-temporal structure of the urban thermal environment (UTE) is important for determining the formation mechanism of the urban heat island (UHI) effect. The empirical or...

The urban heat island (UHI) effect has many adverse impacts on natural and social environments. A better understanding of how complex urban biophysical and social structures affect UHI is crucial to improve urban thermal environments. However, few studies have investigated the effects of 2D/3D urban morphology on land surface temperature (LST) and vertical air temperature simultaneously. Using LST data retrieved from Landsat 8 images and vertical temperatures at different heights collected from unmanned aerial vehicle (UAV) measurements, this study investigated the effects of 2D and 3D urban morphology on the 3D urban thermal environment among different urban function zones (UFZs) in the snow-climate city of Changchun, China. Our main findings are: (1) the average difference in vertical temperature between heights of 1.5 and 100 m was 1.78 °C and the temperature decreasing rate was 0.027 °C/m when the height was lower than 30 m, compared to 0.014 °C/m for 30–100 m. (2) Although 3D metrics had significant impact on LST, the relationships between the 2D metrics and LST were much stronger, accounting for 61% of the variations in LST. Additionally, the 2D composition metrics had stronger correlations with LST than the configuration metrics. The influence of 3D building metrics on LST was context-dependent for different UFZs. Increasing building height could reduce LST in residential UFZs but increase LST in industrial UFZs. (3) The effect of 2D urban morphology on the vertical temperature was stronger than that on the 3D ones when the height was lower than 30 m; however, opposite results were obtained when the height was greater than 30 m. The effects of 2D or 3D metrics on vertical temperature vary depending on whether the height is larger or smaller than a threshold, which is related to the characteristics of the building height. In general, 30 m appeared to be the threshold in our study. (4) The performances of models that used both 2D and 3D metrics to explain both LST and 3D thermal environments were better than those of models that used either 2D or 3D metrics alone, especially in UFZs such as residential areas.

China has experienced extreme urban heat island effects and air pollution associated with rapid urbanization. Optimizing urban ventilation environment could relieve these environmental problems. In this study, an Urban Ventilation Network Model (UVNM) was developed to explore the impact of urban morphology and building height on the urban ventilation condition. The study calculated the ventilation resistance coefficient of building height according to fluid mechanics, and then determined the least cost path among the air inlets and outlets considering the direction and frequency of wind. Eventually, corridors at several different levels of ventilation were extracted by classifying the line densities of least cost paths, which were effectively verified through land surface temperature retrieved from the Landsat Thematic Mapper. The new model is more scientific and convenient than traditional urban construction environmental assessment software in terms of data acquisition and hardware support. The results suggest that urban design based on urban morphology and building height and considering the direction and frequency of wind would be effective for optimizing ventilation to regulate urban environmental problems.

Studies of the spatial extent of surface urban heat island (SUHI or UHISurf) effects require precise determination of the footprint (FP) boundary. Currently available methods overestimate or underestimate the SUHI FP boundary, and can even alter its morphology, due to theoretical limitations on the ability of their algorithms to accurately determine the impacts of the shape, topography, and landscape heterogeneity of the city. The key to determining the FP boundary is identifying background temperatures in reference rural regions. Due to the instability of remote sensing data, these background temperatures should be determined automatically rather than manually, to eliminate artificial bias. To address this need, we developed an algorithm that adequately represents the decay of land surface temperature (LST) from the urban center to surrounding rural regions, and automatically calculates thresholds for reference rural LSTs in all directions based on a logistic curve. In this study, we applied this algorithm with data from the Aqua Moderate Resolution Imaging Spectroradiometer (Aqua/MODIS) 8-day level 3 (L3) LST global grid product to delineate precise SUHI FPs for the Beijing metropolitan area during the summers of 2004–2018 and determine the interannual and diurnal variations in FP boundaries and their relationship with SUHI intensity.

The first-stage of an ecological conservation and restoration project in the Three-River Source Region (TRSR), China, has been in progress for eight years. However, because the ecological effects of this project remain unknown, decision making for future project implementation is hindered. Thus, in this study, we developed an index system to evaluate the effects of the ecological restoration project, by integrating field observations, remote sensing, and process-based models. Effects were assessed using trend analyses of ecosystem structures and services. Results showed positive trends in the TRSR since the beginning of the project, but not yet a return to the optima of the 1970s. Specifically, while continued degradation in grassland has been initially contained, results are still far from the desired objective, ‘grassland coverage increasing by an average of 20%–40%’. In contrast, wetlands and water bodies have generally been restored, while the water conservation and water supply capacity of watersheds have increased. Indeed, the volume of water conservation achieved in the project meets the objective of a 1.32 billion m3 increase. The effects of ecological restoration inside project regions was more significant than outside, and, in addition to climate change projects, we concluded that the implementation of ecological conservation and restoration projects has substantially contributed to vegetation restoration. Nevertheless, the degradation of grasslands has not been fundamentally reversed, and to date the project has not prevented increasing soil erosion. In sum, the effects and challenges of this first-stage project highlight the necessity of continuous and long-term ecosystem conservation efforts in this region.

Lakes under natural conditions are potential indicators of climate change, but limited evidence has been proposed to explicitly explain the mechanisms of large-scale lake changes associated with climate. In this paper, satellite imageries from the 1970s to 2010 were compared to track the dynamic change patterns of plateau lakes. It aims to identify the forcing of climate change on the lakes in plateau regions of China. Results revealed that: (1) widespread expanding trends in the area and abundance of lakes on wetter plateau regions, by increasing precipitation and snow presented a positive effect on lake levels, as well as warming resulted glacier melting and permafrost degrading contributed to expansion of lakes in the regions covered by glaciers on the Tibetan Plateau by 58–62 % and of 13–20 % on the western Inner Mongolia and Xinjiang Plateau; (2) shrinkage lakes in the main portion of the arid regions were mainly caused by the decreasing wind speed resulted water balance change, irrigation and other human utilization of water resources. Although precipitation decreased, wind speed also has the most dominant impact on decreasing evaporation, followed by solar radiation, both of which offset the effect of increasing temperature, especially in eastern Inner Mongolia and Xinjiang Plateau; (3) thawing permafrost led to shrinkage of lakes in an area of seasonal permafrost, the shrinking and splitting of lakes in a discontinuous permafrost zone, and the rising of lake levels in an area of continuous permafrost; (4) the future of the plateau lakes under climate change must be in question, because the glacier and snow melting water is not sustainable for wetter regions, and the increasing water consumption caused by the farmland expansion for arid regions.

Width is one of the key parameters of a shelterbelt. Traditional methods to acquire this width are mainly based on field measurement, which is impractical for monitoring shelterbelts at regional scale. There are many studies analyzing linear objects, but they are not directly applicable to width detection of such objects. In this paper, we analyzed relationships among vegetation fractions retrieved from SPOT5 remote sensing imagery with 10 m × 10 m spatial resolution, shelterbelt area, and shelterbelt width in one pixel. Based on this analysis, we developed a method for recognizing shelterbelt width from a remote sensing image of central western Jilin Province, China. The result was validated by field measurement data and measurement from an aerial image of 0.5 m × 0.5 m spatial resolution. Mean absolute error was 2.40 and 2.73 m respectively, suggesting that the proposed method is feasible and its accuracy is acceptable. The study provides a valuable method for monitoring shelterbelt width across large spatial scales and an accurate input parameter for the recognition of shelterbelt porosity from remote sensing data in future research.

Yield gridded datasets are essential for agricultural land management, food security and harmonious human&ndash, land relationships. Many studies have developed yield spatialization models that are based on cropland areas. However, crop planting areas, phenological dates, and net primary production (NPP) have received minimal attention. This study proposes a novel method to simulate winter wheat yields in China from 2000 to 2015 using crop phenological datasets, phenological observations, and NPP. The results showed that the NPP in the growing season and statistical yield showed a significant positive correlation (R2 = 0.93, p &lt, 0.01). The mean prediction error of the gridded yield dataset was 12.01%. The relative errors of the gridded yield dataset for approximately half of the samples were between &minus, 10% and 10%. Furthermore, the yield distribution was high in the east and low in the west. The high yield was primarily concentrated in the North China Plain, while low yield was observed in eastern Gansu, central Shanxi, southern Hebei, and eastern Sichuan. From 2000 to 2015, the yield mainly showed an increasing trend in the study area, with the average rate of 0.17 t ha-1 yr-1, especially in the North China Plain. This study suggests that NPP is a key indicator to evaluate the yield of winter wheat. Furthermore, this method can be used to generate gridded yield maps along with providing credible and fundamental data for climate change and sustainable agricultural development.

To improve land use efficiency, urban renewal must also consider urban microclimates and heat islands. Existing research has depended on manual interpretation of high-resolution optical satellite imagery to resolve land surface temperature (LST) changes caused by urban renewal; however, the acquired ground time series data tend to be uneven and unique to specific frameworks. The objective of this study was to establish a more general framework to study LST changes caused by urban renewal using multi-source remote sensing data. Specifically, urban renewal areas during 2007–2017 were obtained by integrating Landsat and yearly Phased Array type L-band Synthetic Aperture Radar (PALSAR) images, and LST was retrieved from Landsat thermal infrared data using the generalized single-channel algorithm. Our results showed that urban renewal land (URL) area accounted for 1.88% of urban land area. Relative LST between URL and general urban land (GUL) of Liwan, Yuexiu, Haizhu, and Tianhe districts dropped by 0.88, 0.42, 0.43, and 0.10 K, respectively, whereas those of Baiyun, Huangpu, Panyu, and Luogang districts presented opposite characteristics, with a rise in the LST of 0.98, 1.03, 1.63, and 2.11 K, respectively. These results are attributable to population density, building density, and landscape pattern changes during the urban renewal process.

Cropping intensity has undergone dramatic changes worldwide due to the effects of climate changes and human management activities. Cropping intensity is an important factor contributing to crop production and food security at local, regional and national scales, and is a critical input data variable for many global climate, land surface, and crop models. To generate annual cropping intensity maps at large scales, Moderate Resolution Imaging Spectroradiometer (MODIS) images at 500-m or 250-m spatial resolution have problems with mixed land cover types within a pixel (mixed pixel), and Landsat images at 30-m spatial resolution suffer from low temporal resolution (16-day). To overcome these limitations, we developed a straightforward and efficient pixel- and phenology-based algorithm to generate annual cropping intensity maps over large spatial domains at high spatial resolution by integrating Landsat-8 and Sentinel-2 time series image data for 2016–2018 using the Google Earth Engine (GEE) platform. In this pilot study, we report annual cropping intensity maps for 2017 at 30-m spatial resolution over seven study areas selected according to agro-climatic zones in China. Based on field-scale sample data, the annual cropping intensity maps for the study areas had overall accuracy rates of 89–99%, with Kappa coefficients of 0.76–0.91. The overall accuracy of the annual cropping intensity maps was 93%, with a Kappa coefficient of 0.84. These cropping intensity maps can also be used to enable identification of various crop types from phenological information extracted from the growth cycle of each crop. These algorithms can be readily applied to other regions in China to generate annual cropping intensity maps and quantify inter-annual cropping intensity variations at the national scale with a greatly improved accuracy.

The downstream plain of the Yellow River is experiencing some of the most severe groundwater depletion in China. Although the Chinese government has issued policies to ensure that the Yellow River can provide enough irrigation waters for this region, groundwater levels continue to decrease. Yucheng City was selected as a case study. A new method was designed to classify the cropland into various irrigated cropland. Subsequently, we analyzed data regarding these irrigated-cropland categories, irrigation norms, and the minimum amount of irrigation water being applied to cropland. The results showed that 91.5% of farmland can be classified as double irrigated (by both canal/river and well water), while 8.5% of farmland can be classified as well irrigated. During the irrigation season, the sediments brought in by the river have blocked portions of the canals. This has led to 23% of the double-irrigated cropland being irrigated by groundwater, and it is thus a main factor causing reductions in groundwater supply. These blocked canals should be dredged by local governments to mitigate local groundwater depletion. The method for classifying irrigated cropland from high-resolution images is valid and it can be used in other irrigated areas with a declining groundwater table for the sustainable use of groundwater resources.

The Three-River Headwaters region (TRHR) of China is an important part of the Qinghai-Tibetan Plateau. Although the TRHR is rich in grassland resources, the ecosystem of this area is extremely fragile. Natural and artificial interference have been key to the development of grassland ecosystem spatiotemporal heterogeneity, although the intensity and mode of their influence on ecological processes varies depending on scale; analyses in this area are therefore also scale-dependent. We use multi-scale nested data to analyze the mechanisms underlying the influence of climate change and human activities on grassland net primary productivity (NPP) by applying a multi-level modeling approach. The results of this study show that: (1) The annual grassland NPP of the TRHR has risen in a wavelike pattern over time, increasing by 39.88% overall; (2) Differences of 54.9% and 41.1% in temporal grassland NPP can be attributed to variations between these watersheds as well as county characteristics, and; (3) Although the ‘warm and moist’ climate trend seen over the course of this study has proved beneficial in enhancing grassland NPP, the rate of increase has tended to be faster in relatively dry and warm regions. Economic development and population growth have both exerted negative impacts on grassland NPP.

The impact of land use change on grain potential productivity is one of the most important topics in the research of land use/cover change and its effects. Western Jilin, located on the edge of an ecotone in northern China, and its land use have changed dramatically in recent decades, with significant impact on grain potential productivity. This study evaluated the grain potential productivity in different conditions and analyzed the response to land use change based on land use data, meteorological data and statistical data by using the Global Agro-ecological Zone model. Results showed that (1) grain potential productivity of Western Jilin in 2010 was 19.12 million tons, an increase of 34.8% over 1975 because of changes in land use and in climate, (2) due to land use change, grain potential productivity in the study area increased between 1975 and 2000, however, it decreased between 2000 and 2010, (3) conversion in type of land use and an increase in irrigation percentage caused grain potential productivity to increase by 0.70 million tons and 3.13 million tons respectively between 1975 and 2000, between 2000 and 2010, grain potential productivity had an increase of 0.17 million tons due to the increase in farmland area, but it decreased by 1.88 million tons because the irrigation percentage declined from 36.6% to 24.7%. Therefore, increasing investment in agriculture, improving land quality and increasing the conversion rate of grain potential productivity to actual production would be a better choice for ensuring national food security and achieving sustainable land use.

Ecological projects are an important and vital method to help ecosystem adaptation and restoration in response to the environment change and human interference. The accurate and objective assessment of ecological projects will assist ecosystem management and adaption. This study took the central Tibetan Plateau as the study area, where a series of ecological projects has been implemented since 2005 to prevent grassland degradation by protecting and restoring the grasslands. Our aim is to explore where and to what extent the ecological projects influenced the grassland variation, using SPOT NDVI-based residual trend as an indicator. The results indicated that before the projects (between 1998 and 2004), human-induced degradation characterized the grassland. However, a general grassland restoration was detected after the projects from 2005 to 2012. Moreover, over 60% of project plots had positive trends in the NDVI residuals. From the spatial patterns, project-induced restoration was detected in the western and northern regions, such as Maduo, Dongde and Xinghai counties. For the eastern regions, the human-induced degradation has been generally mitigated and yet not reversed after the projects. Our results indicated that ecological protection and restoration projects in the central Tibetan Plateau have mitigated the grassland degradation and even reversed the degradation in some areas, and also suggested that the NDVI-based residual trend is a useful indicator for assessing the effectiveness of the ecological projects in alpine regions. (C) 2015 Elsevier B.V. All rights reserved.

Rape is a non-grain feedstock with several characteristics that make it suitable for biofuel production, such as high oil yields and low environmental impact. Planting rape on winter fallow fields could allow for seasonal rotation between the bioenergy production and agricultural production. In the present study, the Global Agro-Ecological Zones model was used to estimate the production potential of rapeseed on winter fallow fields in the Yangtze River region from 2010 to 2015. Life cycle assessment was then conducted to calculate energy efficiency and greenhouse gas emissions from the entire energy-producing process and to estimate the number of bioenergy enterprises and their spatial distribution. The results indicated that the total area available of winter fallow fields in the Yangtze River region was 24.93 million ha, accounting for 34.2% of the total cultivated land area. The total yield of winter rapeseed was up to 46.41 million tons (an average yield of 1.86 tons/ha). Thus, the study area could potentially produce net energy of up to 3564 million MJ with energy return on energy investment (EROEI) as high as 1.52–1.84. The total reduction of greenhouse gas emissions may be up to 23.28 million tons, and the total number of bioenergy enterprises could be 589, from which the total biodiesel output could be 167.5 million tons. Hubei, Henan, Anhui and Jiangxi should be prioritized for generating biofuels from rapeseed planted on winter fallow fields.

The quantity and spatial pattern of farmland has changed in China, which has led to a major change in the production potential under the influence of the national project of ecological environmental protection and rapid economic growth during 1990–2010. In this study, the production potential in China was calculated based on meteorological, terrain elevation, soil and land-use data from 1990, 2000 and 2010 using the Global Agro-ecological Zones model. Then, changes in the production potential in response to farmland changes from 1990 to 2010 were subsequently analyzed. The main conclusions were the following. First, the total production potential was 1.055 billion tons in China in 2010. Moreover, the average production potential was 7614 kg/ha and showed tremendous heterogeneity in spatial pattern. Total production in eastern China was high, whereas that in northwestern China was low. The regions with high per unit production potential were mainly distributed over southern China and the middle and lower reaches of the Yangtze River. Second, the obvious spatiotemporal heterogeneity in farmland changes from 1990 to 2010 had a significant influence on the production potential in China. The total production potential decreased in southern China and increased in northern China. Furthermore, the center of growth of the production potential moved gradually from northeastern China to northwestern China. The net decrease in the production potential was 2.97 million tons, which occupied 0.29% of the national total actual production in 2010. Third, obvious differences in the production potential in response to farmland changes from 1990 to 2000 and from 2000 to 2010 were detected. The net increase in the production potential during the first decade was 10.11 million tons and mainly distributed in the Northeast China Plain and the arid and semi-arid regions of northern China. The net decrease in the production potential during the next decade was 13.08 million tons and primarily distributed in the middle and lower reaches of the Yangtze River region and the Huang-Huai-Hai Plain. In general, the reason for the increase in the production potential during the past two decades might be due to the reclamation of grasslands, woodlands and unused land, and the reason for the decrease in the production potential might be urbanization that occupied the farmland and Green for Grain Project, which returned farmland to forests and grasslands.

Terrain, an important limiting factor in land use change, strongly influences agricultural productivity. This study investigated the topographical characteristics of agricultural potential productivity of cropland transformations in China during the first decade of the 21st century, and explored the impacts of cropland transformations with different terrains on agricultural potential productivity as it relates to China’s national food supply. The results showed the production potential of cropland loss was much greater than that of cropland gain in most regions, and topographical characteristics of croplands losses and gains actually impacted the agricultural potential productivity in China. The losses in agricultural potential productivity was serious in regions with good terrain conditions, where the slope is lower than 5°, and the elevation is below 100 m, especially in the middle and lower Yangtze region and the Huang-Huai-Hai region. The situation for cropland loss with better quality, and expanded the worse was severe in China, and this is expected to negatively influence sustainable agricultural development in the future. This study suggests that researchers focus not only on the total area of expanded cropland but also on cropland quality, such as the different terrain conditions of the croplands, to avoid a loss in national agricultural productivity caused by the process of cropland transformation.

China has become increasingly dependent on the international energy market owing to the rapid growth of demand for energy. To develop renewable energy and thus strengthen energy security for the future, it is important to consider the potential of crop residues. This paper contributes to this topic by mobilizing up-to-date statistical and remote-sensing data and by carrying out a geographic and economic analysis. Its assessment shows that China's total output of crop residues in 2010 amounted to 729 million tons, and the quantity could be used for commercial energy production is between 147 and 334 million tons, depending on the competition power of the commercial energy production relative to the traditional uses of crop residues. The analysis also shows that the distribution of crop residues in China is highly uneven. By taking into account the densities of crop residues available for energy production at the grid-cell level, the transportation cost constraints, and the economy-of-scale requirements of energy plants, this study further assesses the geographic distribution of the suitability for establishing crop residue based power plants and bioenergy plants in China.

Improving the understanding of cropland change and its driving factors is a current focus for policy decision-makers in China. The datasets of cropland and cropland changes from the 1970s to the 2000s were used to explore whether climate change has produced spatio-temporal changes to cropland in northern China since the 1970s. Two representative indicators of heat and water resources, which are important determinants of crop growth and productivity, were considered to track climate change, including active accumulated temperatures ≥10 °C (AAT10) and the standardized precipitation evapotranspiration index (SPEI). Our results showed that rapid cropland change has occurred in northern China since the 1970s, and the area of cropland reclamation (10.23 million ha) was much greater than that of abandoned cropland (2.94 million ha). In the 2000s, the area of cropland with AAT10 higher than 3,000 °C·d increased, while the area of cropland with an SPEI greater than 0.25 decreased compared to the 1970s, 1980s and 1990s. It appears that climate warming has provided thermal conditions that have aided rapid cropland reclamation in northern China since the 1970s, and drier climatic conditions did not become a limiting factor for cropland reclamation, especially from the 1990s to the 2000s. Approximately 70 % of cropland reclamation areas were located in warmer but drier regions from the 1990s to the 2000s, and approximately 40 % of cropland abandonment occurred in warmer and wetter conditions that were suitable for agriculture during the periods from the 1970s to the 1980s and the 1990s to the 2000s. Our results suggest that climate change can be considered a driving factor of cropland change in the past several decades in northern China, in addition to socioeconomic factors.

The wetland ecosystem in the “Three-River Headwaters” (TRH) region plays an irreplaceable role in water source conservation, run-off adjustment and biodiversity maintenance. In recent years, assessment of wetland resources affected by climate changes has aroused enormous attention, since it can further protect wetland resources and provide a scientific basis for decision makers. In this study, wetland changes and its response to climate changes in the TRH region from the early 1990s to 2012 were analyzed by remote sensing (RS) image interpretation and climate change trend analysis. The results showed that wetlands occupied 6.3% of the total land area in 2012, and swamps, streams & rivers and lakes were the dominant wetland types in the TRH region. Since the early 1990s, wetlands have undergone great changes, and total wetland area increased by 260.57 km2 (1.17%). Lakes, reservoir & ponds took on continuous increasing trend, but swamps, streams & rivers had a continuous decreasing trend. On the other hand, the wetland area in the Yangtze River basin showed an overall increasing trend, while in the Yellow River and Langcang River basins, it decreased in general. The climate turned from Warm-Dry to Warm-Wet. The average temperature and precipitation increased by 0.91 °C and 101.99 mm, respectively, from 1990 to 2012, and the average humidity index (HI) increased by 0.06 and showing an upward trend and a shifting of the dividing line towards the northwest in both the areas of semi-humid and semi-arid zone. The correlation analysis of wetland changes with meteorological factors from 1990 to 2012 indicated that the regional humidity differences and the interannual variation trend, caused by the change of precipitation and evaporation, was the main driving factor for the dynamic variation of wetland change in the TRH region. In the general, the increase of HI in the THR region since the 1990s, especially in the western TRH region, contributed to wetland increase continuously. The conclusions of this study will provide some scientific references for the management and protection of wetlands in the TRH region, especially for restoration, reconstruction and conservation of degradation wetland.

For urban climatic environments, the urban heat island (UHI) effect resulting from land use and land cover change (LUCC) caused by human activities is rapidly becoming one of the most notable characteristics of urban climate change due to urban expansion. UHI effects have become a significant barrier to the process of urbanization and sustainable development of the urban ecological environment. Predicting the spatial and temporal patterns of the urban heat environment from the spatial relationship between land use and land surface temperature (LST) is key to predicting urban heat environment risk. This study established an Urban Heat Environment Risk Model (UHERM) as follows. First, the urban LST was normalized and classified during three different periods. Second, a Markov model was constructed based on spatio-temporal change in the urban heat environment between the initial year (2005) and middle year (2010), and then a cellular automata (CA) model was used to reveal spatial relationships between the urban heat environments of the two periods and land use in the initial year. The spatio-temporal pattern in a future year (2015) was predicted and the accuracy of the simulation was verified. Finally, the spatio-temporal pattern of urban heat environment risk was quantitatively forecasted based on the decision rule for the urban heat environment risk considering both the present and future status of the spatial characteristics of the urban heat environment. The MODIS LST product and LUCC dataset retrieved from remote sensing images were used to verify the accuracy of UHERM and to forecast the spatio-temporal pattern of urban heat environment risk during the period of 2015&ndash, 2020. The results showed that the risk of urban heat environment is increasing in the Chongqing metropolitan area. This method for quantitatively evaluating the spatio-temporal pattern of urban heat environment risk could guide sustainable growth and provide effective theoretical and technical support for the regulation of urban spatial structure to minimize urban heat environment risk.

Characterization of spatiotemporal variation of water quality is a basic environmental issue with implications for public health in China. Trends in the temporal and spatial distribution of water quality in the Huai River System (HRS) were analyzed using yearly surface water quality data collected from 1982 to 2009. Results showed that the water quality of the main stream deteriorated in the 1990s and early 2000s but has been ameliorated since 2005. The sections that were classified as severely polluted from the monitoring data were located largely in the middle reach. The water quality of HRS fluctuated during the period 1997–2009; it has improved and stabilized since 2005. In terms of spatialized frequency of serious pollution, heavily polluted regions were mostly concentrated in the area along several tributaries of the Ying, Guo and New Sui Rivers as well as the area north of Nansi Lake. These regions decreased from 1997 to 2009, especially after 2005. Our analysis indicated that water pollution in HRS had a close relation with population and primary industry during the period 1997–2009, and implied that spatiotemporal variation of surface water quality could provide a scientific foundation for human health risk assessment of the Huai River Basin.

From early November 2008 to February 2009, lack of rainfall led to severe drought in northern China. More than 9.3 million ha of wheat in six major crop production provinces, including Henan, Anhui, Shandong, Shanxi, Gansu, and Shaanxi, were hit by drought. Supported by Chinese HJ-1 satellite images together with NASA Moderate Resolution Imaging Spectroradiometer (MODIS) data, dynamic monitoring of the drought was conducted. HJ-1 CCD data with 30-m resolution were used to identify cropland information. Spatial–temporal variation of drought was detected using Vegetation Index and Water Index time series data derived from MODIS visible, infrared, and short-wave infrared bands. The influences of drought were classified into five levels based on MODIS-derived 8-day composite Anomaly Water Index (AWI) and field survey data. The results indicated that the drought deteriorated beginning in November 2008 and became most serious in late January 2009. HJ-1 data together with MODIS data proved to be valuable data sources for monitoring soil moisture and drought at a both regional and national scale.

Plantation forests are the most effective and ecologically friendly way of absorbing CO2 and increasing carbon sinks in terrestrial ecosystems; mitigating global warming and beginning ecological restoration. China's forestation rate is the highest in the world, and contributes significantly to the nation's carbon sequestration. We have applied empirical growth curves, scale transformations, field sampling plots, and forest inventory data, to our carbon estimation model, to analyze the carbon sequestration in living biomass and soil organic carbon pools in past and current plantations. Furthermore, the potential carbon sinks of future plantations, 2010-2050, have been simulated. From 1950 to the present, plantations in China sequestered 1.686 Pg C by net uptake into biomass and emissions of soil organic carbon. The carbon stock of China's present plantations was 7.894 Pg C, including 21.4% of the total sequestration as forest biomass and 78.6% as SOC. We project that China's forestation activities will continue to net sequester carbon to a level of 3.169 PgC by 2050, and that carbon stock in plantations will amount to 10.395 Pg C. Spatial patterns of carbon sequestration were dissimilar to those of planting area. On the basis of area, carbon sequestrations were highest in North China, while changes were generally greatest in the Northeast and Southwest regions. (C) 2011 Elsevier Ltd. All rights reserved.

The planted forest area and carbon sequestration have increased significantly in China, because of large-scale reforestation and afforestation in the past decades. In this study, we developed an age-based volume-to-biomass method to estimate the carbon storage by planted forests in China in the period of 1973–2003 based on the data from 1209 field plots and national forest inventories. The results show that the total carbon storage of planted forests was 0.7743 Pg C in 1999–2003, increased by 3.08 times since the early 1970s. The carbon density of planted forests varied from 10.6594 Mg/ha to 23.9760 Mg/ha and increased by 13.3166 Mg/ha from 1973–1976 to 1999–2003. Since the early 1970s, the planted forests in China have been always a carbon sink, and the annual rate of carbon sequestration was 0.0217 Pg C/yr. The carbon storage and densities of planted forests varied greatly in space and time. The carbon storage of Middle South China was in the lead in all regions, which accounted for 23%–36% of national carbon storage. While higher C densities (from 17.79 Mg/ha to 26.05 Mg/ha) were usually found in Northeast China. The planted forests in China potentially have a high carbon sequestration since a large part of them are becoming mature and afforestation continues to grow.

Jingjinji area (namely Beijing, Tianjin and He Bei Province) is one of the three largest regional economic communities in China. Urban expansion has sped up in the past 20 years in this area due to the rapid economic and population growth. Evaluating the land-use suitability for urban growth on a regional scale is an urgent need, because the most suitable areas and the most suitable scale of urban growth can thus be determined accordingly. In order to meet this requirement, remote sensing and geographic information system (GIS) techniques were adopted, and an integrated evaluating model was developed supported by AHP method. The integrated urban development suitability index (UDSI) was calculated using this model. According to the UDSI result, the spatial distribution of urban development suitability and its driving forces were analyzed. Urban boundaries in 1995, 2000 and 2005, which were derived from Landsat TM/ETM+ satellite data, were overlaid on the UDSI map, and the suitable urban develop tendency in this area were discussed. The result of this study indicated that integrated evaluation of urban development could be conducted in an operational way using remote sensing data, GIS spatial analysis technique and AHP modeling method.

Supported by MSS images in the mid and late 1970s, TM images in the early 1990s and TM/ETM images in 2004, grassland degradation in the “Three-River Headwaters” region (TRH region) was interpreted through analysis on RS images in two time series, then the spatial and temporal characteristics of grassland degradation in the TRH region were analyzed since the 1970s. The results showed that grassland degradation in the TRH region were analyzed since the 1970s. The results showed that grassland degradation in the TRH region was a continuous change process which had large affected area and long time scale, and rapidly strengthen phenomenon did not exist in the 1990s as a whole. Grassland degradation pattern in the TRH region took shape initially in the mid and late 1970s. Since the 1970s, this degradation process has taken place continuously, obviously characterizing different rules in different regions. In humid and semi-humid meadow region, grassland firstly fragmentized, then vegetation coverage decreased continuously, and finally “black-soil-patch” degraded grassland was formed. But in semi-arid and arid steppe region, the vegetation coverage decreased continuously, and finally desertification was formed. Because grassland degradation had obviously regional differences in the TRH region, it could be regionalized into 7 zones, and each zone had different characteristics in type, grade, scale and time process of grassland degradation.

Using meteorological data and RS dynamic land-use observation data set, the potential land productivity that is limited by solar radiation and temperature is estimated and the impacts of recent LUCC processes on it are analyzed in this paper. The results show that the influence of LUCC processes on potential land productivity change has extensive and unbalanced characteristics. It generally reduces the productivity in South China and increases it in North China, and the overall effect is increasing the total productivity by 26.22 million tons. The farmland reclamation and original farmlands losses are the primary causes that led potential land productivity to change. The reclamation mostly distributed in arable-pasture and arable-forest transitional zones and oasises in northwestern China has made total productivity increase by 83.35 million tons, accounting for 3.50% of the overall output. The losses of original farmlands driven by built-up areas invading and occupying arable land are mostly distributed in the regions which have rapid economic development, e.g. Huang-Huai-Hai plain, Yangtze River delta, Zhujiang delta, central part of Gansu, southeast coastal region, southeast of Sichuan Basin and Urumqi-Shihezi. It has led the total productivity to decrease 57.13 million tons, which is 2.40% of the overall output.

The Three-Rivers Headwaters region (TRHR) is an ecological shelter located in the northeast of the Tibetan Plateau, China, that provides environmental protection and regional sustainable development. This region also provides ecosystem services including water supply and soil conservation and exerts major impacts on both its surroundings, as well as the whole of China. A number of ecological restoration projects have been initiated within the TRHR since 2000, including the creation of a natural reserve. Analyses of trends in land use/land cover (LULC), net primary productivity (NPP), water yield and soil conservation within the TRHR are presented based on regional climate and land use datasets and utilizing the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model in tandem with the double mass curve (DMC) approach. The results of this study reveal a series of correlations between ecosystem services and lead to four distinct conclusions. First, the amount of variation between 2000 and 2012 in each LULC type within the TRHR was small. In particular, grassland substitution occurred in high-altitude areas and increased in central areas. Second, NPP, water yield, soil conservation amount and the volume of exported phosphorus (P) decreased along an east-west gradient with values of 64.44%, 38.81%, 7.37% and −49.98% recorded, respectively, between 2000 and 2012. The ecosystem services of the Yellow River basin to the east of the TRHR generally improved over the study period, while those of the Yangtze River and Lancang River basins where enhanced to a lesser extent, and obvious degradation was observed in some local areas. Third, the ecosystem services provided by forested land were highest, followed by grassland and cultivated land, respectively. Fourth, synergistic relationships were observed within the TRHR between NPP, water yield and soil conservation amount, indicating that increasing NPP simultaneously increased the values for these related factors. Synergistic relationships were also recorded between water yield and the amount of exported P, suggesting that increases in the former cause a reduction in water purity.

Atmospheric pollution has become a significant challenge in Beijing metropolitan region, China. In this study, wavelet analysis and gray analysis were proposed to explore the temporal characteristics of particulate matter (PM10) and its relationships with meteorological factors during 2001-2012. The analysis indicated that air quality had got better significantly over the last decade. It was clearly interannual, seasonal, and monthly variation of atmospheric pollution, which represented that the air quality was the worst in spring, and got better in summer, subsequently tended to be more serious in autumn and winter. Generally atmospheric pressure was the most important meteorological feature influencing on PM10, followed by relative humidity and wind speed. However, the dominant meteorological factors influencing the atmospheric pollution were different in the four seasons. The results suggest that urban design and effective measures based on the relationship between meteorological factors and PM10 would be effective for improving atmospheric pollution.

To protect the water tower’s ecosystem environment and conserve biodiversity, China has been implementing a huge payment program for ecosystem services in the three rivers source region. We explored here the dynamics of grassland degradation and restoration from 1990 to 2012 and its relationships with climate mitigation in the TRSR to provide a definite answer as to the forcing and response of grassland degradation and restoration to climate change. Then we estimated its potential of climate mitigation benefits to address the question of whether ecological restoration could be effective in reversing the decline of ecosystem carbon mitigation service. The trend of average annual temperature and precipitation observed by meteorological stations were approximately increased. Compared before and after 2004, the area of grassland degradation was increased slightly. However, nearly one-third of degraded grassland showed improvement, and the grassland vegetation coverage showed significant increase. Comparing current grassland vegetation coverage with healthy vegetation cover with the same grass type, nearly half of the area still needs to further restore vegetation cover. The grassland degradation resulted in significant carbon emissions, but the restoration to its healthy status has been estimated to be technical mitigation potential.

The multiple cropping practice is essential to agriculture because it has been shown to significantly increase the grain yield and promote agricultural economic development. In this study, potential multiple cropping systems in China are calculated based on meteorological observation data by using the Agricultural Ecology Zone (AEZ) model. Following this, the changes in the potential cropping systems in response to climate change between the 1960s and the 2010s were subsequently analyzed. The results indicate that the changes of potential multiple cropping systems show tremendous heterogeneity in respect to the spatial pattern in China. A key finding is that the magnitude of change of the potential cropping systems showed a pattern of increase both from northern China to southern China and from western China to eastern China. Furthermore, the area found to be suitable only for single cropping decreased, while the area suitable for triple cropping increased significantly from the 1960s to the 2000s. During the studied period, the potential multiple cropping index (PMCI) gap between rain-fed and irrigated scenarios increased from 18% to 24%, which indicated noticeable growth of water supply limitations under the rain-fed scenario. The most significant finding of this research was that from the 1960s to the 2000s climate change had led to a significant increase of PMCI by 13% under irrigated scenario and 7% under rain-fed scenario across the whole of China. Furthermore, the growth of the annual mean temperature is identified as the main reason underlying the increase of PMCI. It has also been noticed that across China the changes of potential multiple cropping systems under climate change were different from region to region.

climatic resource is a primary condition of determining agricultural development of area. This paper regards land use pattern as the unit of calculating, utilize the meteorological materials day by day of 1991-2000 year, and estimates the impact of recent climate fluctuation on potential productivity for crops in Northeast China. The result shows: because the climate has become warm in Northeast crop growing period in the past 10 years (The temperature has increased 2.19 degrees C and the annual precipitation decreased 305.76mm), the crop potential productivity generally reduced by 6.45%. Moreover, the change of the precipitation is the main reason causing the different trends of crop potential productivity in different area.