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Soil moisture plays an important role in crop yield estimation, irrigation management, etc. Remote sensing technology has potential for large-scale and high spatial soil moisture mapping. However, offline remote sensing data processing is time-consuming and resource-intensive, and significantly hampers the efficiency and timeliness of soil moisture mapping. Due to the high-speed computing capabilities of remote sensing cloud platforms, a High Spatial Resolution Soil Moisture Estimation Framework (HSRSMEF) based on the Google Earth Engine (GEE) platform was developed in this study. The functions of the HSRSMEF include research area and input datasets customization, radar speckle noise filtering, optical-radar image spatio-temporal matching, soil moisture retrieving, soil moisture visualization and exporting. This paper tested the performance of HSRSMEF by combining Sentinel-1, Sentinel-2 images and in-situ soil moisture data in the central farmland area of Jilin Province, China. Reconstructed Normalized Difference Vegetation Index (NDVI) based on the Savitzky-Golay algorithm conforms to the crop growth cycle, and its correlation with the original NDVI is about 0.99 (P < 0.001). The soil moisture accuracy of the random forest model (R2 = 0.942, RMSE = 0.013 m3/m3) is better than that of the water cloud model (R2 = 0.334, RMSE = 0.091 m3/m3). HSRSMEF transfers time -consuming offline operations to cloud computing platforms, achieving rapid and simplified high spatial resolution soil moisture mapping. [ABSTRACT FROM AUTHOR]

Algal blooms in lakes have become a common global environmental problem. Nowadays, remote sensing is widely used to monitor algal blooms in lakes due to the macroscopic, fast, real-time characteristics. However, it is often difficult to distinguish between algal blooms and aquatic vegetation due to their similar spectral characteristics. In this paper, we used modified vegetation presence frequency index (VPF) based on Moderate-resolution Imaging Spectroradiometer (MODIS) imagery to distinguish algal blooms from aquatic vegetation, and analyzed the spatial and temporal variations of algal blooms and aquatic vegetation from a phenological perspective for five large natural lakes with frequent algal bloom outbreaks in China from 2019 to 2020. We simplified the VPF method to make it with a higher spatial transferability so that it could be applied to other lakes in different climatic zones. Through accuracy validation, we found that the modified VPF method can effectively distinguish between algal blooms and aquatic vegetation, and the results vary from lake to lake. The highest accuracy of 97% was achieved in Hulun Lake, where the frequency of algal outbreaks is low and the extent of aquatic vegetation is stable, while the lowest accuracy of 76% was achieved in Dianchi Lake, which is rainy in summer and the lake is small. Analyses suggests that the time period when algal blooms occur most frequently might not coincide with that when they have the largest area. However, in most cases these two are close in terms of time period. The modified VPF method has a broad scope of application, is easy to implement, and has a high practical value. Furthermore, the method could be established using only a small amount of measured data, which is useful for water quality monitoring on large spatial scales. [ABSTRACT FROM AUTHOR]

With rapid urban development in China in the last two decades, the three-dimensional (3D) characteristic has been the main feature of urban morphology. However, the vast majority of researches of urban growth have focused on the planar area (two-dimensional (2D)) expansion. Few studies have been conducted from a 3D perspective. In this paper, the 3D urban expansion of the Yangzhou City, Jiangsu Province, China from 2003 to 2012 was evaluated based on Geographical Information System (GIS) tools and high-resolution remote sensing images. Four indices, namely weighted average height of buildings, volume of buildings, 3D expansion intensity and 3D fractal dimension are used to quantify the 3D urban expansion. The weighted average height of buildings and the volume of buildings are used to illustrate the temporal change of the 3D urban morphology, while the other two indices are used to calculate the expansion intensity and the fractal dimension of the 3D urban morphology. The results show that the spatial distribution of the high-rise buildings in Yangzhou has significantly spread and the utilization of the 3D space of Yangzhou has become more efficient and intensive. The methods proposed in this paper laid a foundation for a wide range of study of 3D urban morphology changes. [ABSTRACT FROM AUTHOR]

Extreme heat events have serious effects on human daily life. Accurately capturing the dynamic variance of extreme high-temperature distributions in a timely manner is the basis for analyzing the potential impacts of extreme heat, thereby informing risk prevention strategies. This paper demonstrates the potential application of multiple source remote sensing data in mapping and monitoring the extreme heat events that occurred on Aug. 8, 2013 in Jiangsu Province, China. In combination with MODIS products, the thermal sharpening (TsHARP) method and a binary linear model are compared to downscale the original daytime FengYun 2F (FY-2F) land surface temperature (LST) imagery, with a temporal resolution of 60 min, from 5 km to 1 km. Using the meteorological measurement data from Nanjing station as the reference, the research then estimates the instantaneous air temperature by using an iterative computation based on the Surface Energy Balance Algorithm for Land (SEBAL), which is used to analyze the spatio-temporal air temperature variance. The results show that the root mean square error (RMSE) of the LST downscaled from the binary linear model is 1.30°C compared to the synchronous MODIS LST, and on this basis the estimated air temperature has the RMSE of 1.78°C. The spatial and temporal distribution of air temperature variance at each geographical location from 06:30 to 18:30 can be accurately determined, and indicates that the high temperature gradually increases and expands from the city center. For the spatial distribution, the air temperature and the defined scorching temperature proportion index increase from northern to middle, to southern part of Jiangsu, and are slightly lower in the eastern area near the Yellow Sea. In terms of temporal characteristics, the percentage of area with air temperature above 37°C in each city increase with time after 10:30 and reach the peak value at 14:30 or 15:30. Then, they decrease gradually, and the rising and falling trends become smaller from the southern cities to the northern regions. Moreover, there is a distinct positive relationship between the percentage of area above 37°C and the population density. The above results show that the spatio-temporal distributions of heat waves and their influencing factors can be determined by combining multiple sources of remotely sensed image data. [ABSTRACT FROM AUTHOR]

Sri Lanka is experiencing speedy urbanization by converting the agriculture land and other natural land cover into built-up land. The urban population of Sri Lanka is expected to reach to 60% by 2030 from 14% in 2010. The rapid growth in urban population and urban areas in Sri Lanka may cause serious socioeconomic disparities, if they are not handled properly. Thus, planners in Sri Lanka are in need of information about past and future urban growth patterns to plan a better and sustainable urban future for Sri Lanka. In this paper, we analyzed the characteristics of past land use and land cover trends in Matara City of Sri Lanka from 1980 to 2010 to assess the historic urban dynamics. The land use change detection analysis based on remote sensing datasets reveal that the conversion of homestead/garden and paddy into urban land is evident in Matara City. The historic urban trends are projected into the near future by using SLEUTH urban growth model to identify the hot spots of future urbanization and as well as the urban growth patterns in Matara City up to the basic administrative level, i.e., Grama Niladari Divisions (GND). The urban growth simulations for the year 2030 reveal that 29 GNDs out of 66 GNDs in Matara City will be totally converted into urban land. Whereas, 28 GNDs will have urban land cover from 75% to 99% by 2030. The urban growth simulations are further analyzed with respect to the proposed Matara city development plan by the Urban Development Authority (UDA) of Sri Lanka. The results show that the UDA's city development plan of Matara will soon be outpaced by rapid urbanization. Based on the calibration and validation results, the SLEUTH model proved to be a useful planning tool to understand the near future urbanization of Sri Lankan cities. [ABSTRACT FROM AUTHOR]

This paper firstly investigated the land-use and land-cover change (LUCC) in the Hun-Taizi River watershed, Northeast China from 1988 to 2004 based on remotely sensed images and geographic information systems (GIS) technology. Then, using the famous land-use change model of Conversion of Land Use and its Effects at Small regional extent (CLUE-S), this paper simulated the land use changes under historical trend (HT), urban planning (UP) and ecological protection (EP) scenarios considering urban planning and ecological protection over the next 20 years. The simulated results under UP scenario in 2020 were compared with the planning map to assess the feasibility of using land-use change model to guide regional planning. Results show that forest land, dry farmland, paddy, and shrub land were the main land-use categories. Paddy and dry farmland being converted to urban area and rural settlement characterized the land-use change from 1988 to 2004. The main land-use categories changed over time. Landscape-pattern fragmentation will be worse under HT and UP scenarios, but better in EP scenario. The comparing results of simulated map with planning map in 2020 show that land-use change model is powerful tool to guide regional planning. Land-use scenarios can support regional planning and policy-making through analyzing future consequences scientifically. [ABSTRACT FROM AUTHOR]

Farmland protection and delimitation in the urban fringe considers not only natural factors but also the spatial characters and site factors. Taking Daxing District, Beijing in China as a case study, this paper used landscape ecology and power-law methods to analyze and evaluate farmland loss during the period of 2004-2007 based on the interpretation results of SPOT5 remote sensing images in 2004 and 2007. At the patch level, we selected four landscape indices, namely patch size, shape index, the nearest neighbor distance between farmland and construction land (including residential land and other construction land), and cropping type, to evaluate the risk of farmland loss and establish a farmland site analysis indicator system. The results showed that patch size and shape index have a significant positive correlation with farmland loss, whereas the distance to construction land has a clear negative correlation with farmland loss. As regards cropping type, fallow farmland is much easier for non-agricultural use than cultivated farmland. The relative transition ratio among vegetable land, fallow farmland and cultivated farmland is 1:5.6:1. The patch size of lost farmland follows a power-law distribution, indicating that not only small parcels but also large parcels can be lost. Patch size less than 4 ha or more than 15 ha is in high loss risk, between 4 ha and 10 ha in medium loss risk, and larger than 10 ha and less than 15 ha in low risk. Farmland with a more regular shape has a higher likelihood of loss. Patch shape index less than 2.0 is in high loss risk, between 2.0 and 3.0 in medium loss risk, and larger than 3.0 in low risk. Construction land has a varying impact on farmland loss, the residential land effected distance is 1000 m, and that of the other construction land is 2000 m. This analysis showed the relationships between site factors and farmland loss, and the analysis framework can provide support and reference for farmland protection and delimitation of prime farmland in China. [ABSTRACT FROM AUTHOR]

Mechanism and modeling of the land subsidence are complex because of the complicate geological background in Beijing, China. This paper analyzed the spatial relationship between land subsidence and three factors, including the change of groundwater level, the thickness of compressible sediments and the building area by using remote sensing and GIS tools in the upper-middle part of alluvial-proluvial plain fan of the Chaobai River in Beijing. Based on the spatial analysis of the land subsidence and three factors, there exist significant non-linear relationship between the vertical displacement and three factors. The Back Propagation Neural Network (BPN) model combined with Genetic Algorithm (GA) was used to simulate regional distribution of the land subsidence. Results showed that at field scale, the groundwater level and land subsidence showed a significant linear relationship. However, at regional scale, the spatial distribution of groundwater depletion funnel did not overlap with the land subsidence funnel. As to the factor of compressible strata, the places with the biggest compressible strata thickness did not have the largest vertical displacement. The distributions of building area and land subsidence have no obvious spatial relationships. The BPN-GA model simulation results illustrated that the accuracy of the trained model during fifty years is acceptable with an error of 51% of verification data less than 20 mm and the average of the absolute error about 32 mm. The BPN model could be utilized to simulate the general distribution of land subsidence in the study area. Overall, this work contributes to better understand the complex relationship between the land subsidence and three influencing factors. And the distribution of the land subsidence can be simulated by the trained BPN-GA model with the limited available dada and acceptable accuracy. [ABSTRACT FROM AUTHOR]

This paper principally focuses on land use dynamics, urban expansion and underlying driving forces in the Natural Wetland Distribution Area (NWDA) of Fuzhou City in the southeastern China. Based on time series Landsat TM/ETM+ imageries and historical data, relationships between urban land expansion and its influencing factors from 1989 to 2009 were analyzed by using an integrated approach of remote sensing (RS) and geographic information system (GIS) techniques. The results showed that built-up land increased from 151.16 km in 1989 to 383.76 km in 2009. Approximately 64.25% of the newly emerging built-up land was converted from cropland (29.47%), forest and shrub (25.78%), water (3.73%), wetland (4.61%), and bare land (0.66%) during 1989 and 2009. With a remarkable decrease in cropland, the proportion of non-agricultural population increased by 23.6%. Moreover, rapid development of infrastructures, facilities, industrial parks, and urban and rural settlements along the Minjiang River resulted in the eastward and southward expansion of built-up land. Additionally, the growth pattern of built-up land in the NWDA is highly correlated with socio-economic factors, including the gross domestic product (GDP), GDP per capita, and structure of industry. As a result, the observed environmental degradation such as loss of cropland and wetland due to heavy pressure of rapid urbanization have greatly impaired the carrying capacity of city. Thus, in addition to scientific and rational policies towards minimizing the adverse effects of urbanization, coordination between the administrative agencies should be urgently strengthened to balance the conflicts between urban development and ecological conservation to make sure the sustainable land use. [ABSTRACT FROM AUTHOR]

Spectral remote sensing technique is usually used to monitor flood and waterlogging disaster. Although spectral remote sensing data have many advantages for ground information observation, such as real time and high spatial resolution, they are often interfered by clouds, haze and rain. As a result, it is very difficult to retrieve ground information from spectral remote sensing data under those conditions. Compared with spectral remote sensing technique, passive microwave remote sensing technique has obvious superiority in most weather conditions. However, the main drawback of passive microwave remote sensing is the extreme low spatial resolution. Considering the wide application of the Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) data, an AMSR-E data unmixing method was proposed in this paper based on Bellerby's algorithm. By utilizing the surface type classification results with high spatial resolution, the proposed unmixing method can obtain the component brightness temperature and corresponding spatial position distribution, which effectively improve the spatial resolution of passive microwave remote sensing data. Through researching the AMSR-E unmixed data of Yongji County, Jilin Provinc, Northeast China after the worst flood and waterlogging disaster occurred on July 28, 2010, the experimental results demonstrated that the AMSR-E unmixed data could effectively evaluate the flood and waterlogging disaster. [ABSTRACT FROM AUTHOR]

Wetland databases can provide the basic data that necessary for the protection and management of wetlands. A large number of wetland databases have been established in the world as well as in China. In this paper, we review China's wetland databases based on remote sensing (RS) technology after introducing the background theory to the application of RS technology in wetland surveys. A key conclusion is that China's wetland databases are far from sufficient in fulfilling protection and management needs. Our recommendations focus on the use of the hyper-spectral imagery, microwave data, multi-temporal images, and automatic classifications in order to improve the accuracy and efficiency of wetland inventory. Further, attention should also be paid to detect major biophysical features of wetlands and build wetland databases in years after the 1980s in China. Considering that great gap exists between RS experts and wetland experts, further cooperation between wetland scientists and RS scientists are needed to promote the application of RS in the foundation of wetland databases. [ABSTRACT FROM AUTHOR]

Biodiversity is vital for the integrity and stability of ecosystems and sustainable development. Karst regions of Southwest China is featured for undulating and broken karst terrain as well as high plant diversity. Land use changes induced by the growing population and expanding human settlement have threatened biodiversity preservation in this region. However, the impact of urban expansion on plant diversity remains unclear here. This study focuses on how expanding countryside landscapes affect the recovery rate of plant diversity and demonstrate how urban expansion affects plant diversity conservation in karst regions of Southwest China. In situ biodiversity investigations and multisource remote sensing images were combined to analyze the role of human settlement evolution in the conservation of plant diversity using descriptive statistics and regression analysis. Unmanned vehicle images, historical aerial photographs, and long-term remote sensing images were used to observe the human settlement pattern changes over 40 yr and found that plant diversity is restored faster in countryside ecosystems than in island ecosystems restricted by water. Forests, however, contribute the most to plant diversity conservation in both ecosystems. While the forest area is stable during urban expansion, massive forest patches play an essential role in plant diversity conservation. Arable lands and grasslands shrank but with a fragmenting trend, which was conducive to preserving plant diversity, whereas increased and regularized large patches of built-up areas were not beneficial to plant diversity. Accordingly, forest protection should be prioritized to coordinate future socioeconomic development and plant diversity conservation in karst and broader regions. Furthermore, large built-up patches should be limited, and the irregularity should be improved during urban expansion. Irregular shaped cultivated land and grassland were suggested to promote biological information exchanges as landscape corridors. [ABSTRACT FROM AUTHOR]

Inspired by recent significant agricultural yield losses in the eastern China and a missing operational monitoring system, we developed a comprehensive drought monitoring model to better understand the impact of individual key factors contributing to this issue. The resulting model, the 'Humidity calibrated Drought Condition Index' (HcDCI) was applied for the years 2001 to 2019 in form of a case study to Weihai County, Shandong Province in East China. Design and development are based on a linear combination of the Vegetation Condition Index (VCI), the Temperature Condition Index (TCI), and the Rainfall Condition Index (RCI) using multi-source satellite data to create a basic Drought Condition Index (DCI). VCI and TCI were derived from MODIS (Moderate Resolution Imaging Spectroradiometer) data, while precipitation is taken from CHIRPS (Climate Hazards Group InfraRed Precipitation with Station data) data. For reasons of accuracy, the decisive coefficients were determined by the relative humidity of soils at depth of 10–20 cm of particular areas collected by an agrometeorological ground station. The correlation between DCI and soil humidity was optimized with the factors of 0.53, 0.33, and 0.14 for VCI, TCI, and RCI, respectively. The model revealed, light agricultural droughts from 2003 to 2013 and in 2018, while more severe droughts occurred in 2001 and 2002, 2014–2017, and 2019. The droughts were most severe in January, March, and December, and our findings coincide with historical records. The average temperature during 2012–2019 is 1°C higher than that during the period 2001–2011 and the average precipitation during 2014–2019 is 192.77 mm less than that during 2008–2013. The spatio-temporal accuracy of the HcDCI model was positively validated by correlation with agricultural crop yield quantities. The model thus, demonstrates its capability to reveal drought periods in detail, its transferability to other regions and its usefulness to take future measures. [ABSTRACT FROM AUTHOR]

In China, promoting the development of coastal areas has been included in a series of national strategic development plans. At the same time, many marine environmental problems have been associated with the rapid development of coastal sea use. In order to quantify the impact of human activities on the coast, the characteristics of coastlines and near-shore sea use of Liaodong Bay, Northeast China, were first classified using multi-source, remotely sensed imagery using automatic or semi-automatic extraction methods for five periods between 1993 and 2015. Sea use dynamics and coastline dynamics resulting from human activates were analyzed. Results showed a significant trend of continuous growth in sea use and a progressive increase in the total length of artificial coastline, but a noticeable loss of natural coastline during the five periods. Reclaimed land and enclosed areas were the main types of sea use. Most coastal human activities were distributed in the northern part of the bay. In recent years, rapid industrialization and urbanization in China's coastal areas have promoted large-scale land reclamation. Accordingly, the observed coastline changes during each period had a close relationship with coastal development and sea area utilization. Based on marine functional zoning (MFZ), the sea use carrying capacity was evaluated by means of indexes to describe human exploitation of the marine and coastal environments in the bay. This showed that the intensity of coastal utilization in Liaodong Bay has increased year-on-year. Sea use carrying capacity reached a 'critically loaded' state by 2008 and was 'overloaded' by 2015. [ABSTRACT FROM AUTHOR]

Recent advances in remote sensing technology and methods have resulted in the development of an evapotranspiration (ET) product from the Moderate Resolution Imaging Spectrometer (MOD16). The accuracy of this product however has not been tested for coastal wetland ecosystems. The objective of this study therefore is to validate the MOD16 ET product using data from one eddy covariance flux tower situated in the Panjin coastal wetland ecosystem within the Liaohe River Delta, Northeast China. Cumulative ET data over an eight-day period in 2005 from the flux tower was calculated to coincide with the MOD16 products across the same period. Results showed that data from the flux tower were inconsistent with that gained form the MOD16 ET. In general, results from Panjin showed that there was an underestimation of MOD16 ET in the spring and fall, with Biases of-2.27 and-3.53 mm/8d, respectively (-40.58% and-49.13% of the observed mean). Results for Bias during the summer had a range of 1.77 mm/8d (7.82% of the observed mean), indicating an overestimation of MOD16 ET. According to the RMSE, summer (6.14 mm/8d) achieved the lowest value, indicating low accuracy of the MOD16 ET product. However, RMSE (2.09 mm/8d) in spring was the same as that in the fall. Relationship between ET and its relevant meteorological parameters were analyzed. Results indicated a very good relationship between surface air temperature and ET. Meanwhile a significant relationship between wind speed and ET also existed. The inconsistent comparison of MOD16 and flux tower-based ET are mainly attributed to the parameterization of the Penman-Monteith model, flux tower measurement errors, and flux tower footprint vs. MODIS pixels. [ABSTRACT FROM AUTHOR]

The sub-pixel impervious surface percentage (SPIS) is the fraction of impervious surface area in one pixel, and it is an important indicator of urbanization. Using remote sensing data, the spatial distribution of SPIS values over large areas can be extracted, and these data are significant for studies of urban climate, environment and hydrology. To develop a stabilized, multi-temporal SPIS estimation method suitable for typical temperate semi-arid climate zones with distinct seasons, an optimal model for estimating SPIS values within Beijing Municipality was built that is based on the classification and regression tree (CART) algorithm. First, models with different input variables for SPIS estimation were built by integrating multi-source remote sensing data with other auxiliary data. The optimal model was selected through the analysis and comparison of the assessed accuracy of these models. Subsequently, multi- temporal SPIS mapping was carried out based on the optimal model. The results are as follows: 1) multi-seasonal images and nighttime light (NTL) data are the optimal input variables for SPIS estimation within Beijing Municipality, where the intra-annual variability in vegetation is distinct. The different spectral characteristics in the cultivated land caused by the different farming characteristics and vegetation phenology can be detected by the multi-seasonal images effectively. NLT data can effectively reduce the misestimation caused by the spectral similarity between bare land and impervious surfaces. After testing, the SPIS modeling correlation coefficient (r) is approximately 0.86, the average error ( AE) is approximately 12.8%, and the relative error ( RE) is approximately 0.39. 2) The SPIS results have been divided into areas with high-density impervious cover (70%-100%), medium-density impervious cover (40%-70%), low-density impervious cover (10%-40%) and natural cover (0%-10%). The SPIS model performed better in estimating values for high-density urban areas than other categories. 3) Multi-temporal SPIS mapping (1991-2016) was conducted based on the optimized SPIS results for 2005. After testing, AE ranges from 12.7% to 15.2%, RE ranges from 0.39 to 0.46, and r ranges from 0.81 to 0.86. It is demonstrated that the proposed approach for estimating sub-pixel level impervious surface by integrating the CART algorithm and multi-source remote sensing data is feasible and suitable for multi-temporal SPIS mapping of areas with distinct intra-annual variability in vegetation. [ABSTRACT FROM AUTHOR]

To evaluate urban human settlement, we propose a human settlement environment development index (HSEDI) model by choosing vegetation coverage, land surface temperature, impervious surfaces, slope, wetness, and water condition as the evaluation factors. We applied the proposed model to Xuzhou City, Jiangsu Province, China. Landsat-5 Thematic Mapper (TM) images from 1998 to 2010 and digital elevation model (DEM) data with a 30-m resolution were used to calculate the values of the six evaluation factors. The HSEDI value in Xuzhou City was found to be between 2.24 and 8.10 from 1998 to 2010, and it was further divided into five levels, uninhabitable, moderately uninhabitable, generally inhabitable, moderately inhabitable, and inhabitable. The best HSEDI value was in 2007. The generally inhabitable region was about 100.98 km, covering 30.87% of the total area in 2007; the moderately inhabitable region was about 170.58 km covering 52.15% of the total area; the inhabitable region was about 32.03 km, covering 9.79% of the total area; the percentage of the uninhabitable region was zero; and that of the moderately uninhabitable region was very small, less than 1.00%. Moreover, we analyzed the habitability in the respect of spatial patterns and change detection. Results show that the degraded regions of habitability quality are mainly located in the urban fringe and the improved regions are mainly located in the main urban and rural areas. Reason for the degraded habitability quality is the rapid progress of urbanization. However, the increase in urban green spaces and the construction of the main urban area promoted the improved habitability quality. Besides, we further analyzed socio-economic and socio-demographic data to confirm the results of the habitability analysis. The results indicate that the human settlement in Xuzhou City is in a satisfactory condition, but some efforts should be made to control the possible uninhabitable and moderately uninhabitable regions, and to improve the quality of the generally inhabitable regions. [ABSTRACT FROM AUTHOR]

If urban sprawl is to be avoided in China in the next ten years, it is not only crucial to understand the overall history, current status, and future trends of urban expansion there, but also these differences, and this is presently lacking. In this study, remotely sensed images with approximately 30 m spatial resolution were used to quantitatively assess the spatial and temporal patterns of urban expansion of 60 Chinese cities (1973-2013). Urban-expansion-process curves of the cities studied were drawn using annual expansion area as an indicator. Curve similarity analysis generated four basic process modes of urban expansion in China. These included cities that: 1) peaked around 2004 and then decelerated; 2) peaked around 2010 and then decelerated; 3) showed sustained acceleration, and 4) showed continued deceleration. Four basic process modes represented cities under different levels of development stage. Geographic location was found to be the most related characteristic to urban expansion process. Regional development policies at the national level in each region also showed highly temporal consistency with fluctuation characteristics of urban expansion process. Urban characteristic such as population size and administrative level were not found to be significantly related to urban expansion-process modes. Understanding the basic process-mode categories well is extremely important for future regional-balance planning and development of macroeconomic policies. [ABSTRACT FROM AUTHOR]

As the 'economic engines' of China, coastal cities have developed and expanded considerably since the 1970s. In this study, information on the urban expansion process of Chinese coastal cities from the 1970s to 2013 was retrieved. Through the analysis of stage characteristics, spatial expansion modes, influences on land use, centroid shifts, and spatial morphological evolutions, the spatial differences of coastal urban expansion were revealed. Results indicate that 1) the expansion stages of southern coastal cities are more complex than those of northern coastal cities, and the expansion ranges and speeds of the former are far higher than those of the latter; 2) the spatial expansion of southern coastal cities mostly adopt a single mode, whereas northern coastal cities mostly adopt a mixed mode; 3) significant spatial differences in the occupations of different land sources exist between the south and the north along the coastline; 4) the centroid of coastal cities tends to migrate toward the coastline, and the centroid shift distances of southern coastal cities are clearly higher than those of northern coastal cities; and 5) the spatial morphology of southern coastal cities tends to be compact, whereas that of northern coastal cities tends to be loose. Policies have a powerful significance in terms of guiding urban expansion and its spatial differences in coastal cities. Urban expansion in coastal cities will encounter new opportunities and challenges under the guidance of new types of urbanization strategies. [ABSTRACT FROM AUTHOR]

Based on remote sensing and GIS techniques, land use maps in 2000, 2005 and 2010 in China's coastal zone were produced, and structural raster data of land use were further generated to calculate land use intensity comprehensive index (LUICI) for analyzing land use spatial-temporal characteristics at 1 km scale. Results show that: 1) from the perspective of spatial patterns of landforms at a macro scale, there is a significant difference in land use intensity between the north and the south of China's coastal zone. Hotspots of changes mainly concentrated in metropolitan areas, estuaries and coastal wetlands; 2) elevation is an important factor that controlling land use spatial patterns at local scale. Land use intensity is much higher within areas below the elevation of 400 m and it decreased significantly as the elevation increasing; 3) there is a significant land-ocean gradient for land use intensity, which is low in island and near-shore areas, but high in the regions that 4-30 km far away the coastline because of much intensive human activities; however, in recent decades land use intensity had been promoted significantly in low near-shore area due to extensive sea reclamations; 4) significant differences of land use intensity were also found among provincial administrative units. A rising trend of land use intensity was found in provincial-level administrative units from 2000 to 2010. To sum up, elevation, land-ocean gradient, socio-economic status and policy are all influencing factors to the spatial patterns and temporal variations of land use intensity in China's coastal zone. [ABSTRACT FROM AUTHOR]

Wetlands are highly productive natural ecosystems, providing valuable goods and services. There is growing interest in transferring ecosystem service value from the existing wetlands studied to other wetlands ecosystems at a large geographic scale. The benefit transfer method uses the known values from wetlands to predict the value of other wetland sites. This methodology requires only limited time and resources. The present study calculated the value of the ecological services provided by lake and marsh wetlands in China in terms of biodiversity indices, water quality indices and economic indices. Basic data on wetlands were obtained through remote sensing images. The results show that: 1) The total ecosystem service value of the lake and marsh wetlands in 2008 was calculated to be 8.1841 × 10 United States Dollars (USD), with the marsh and lake wetlands contributing 5.6329 × 10 and 2.5512 × 10 USD, respectively. Values of marsh ecosystem service were concentrated in Heilongjiang Province (2.5516 × 10 USD), Qinghai Province (1.2014 × 10 USD), and Inner Mongolia Autonomous Region (1.1884 × 10 USD). The value of the lakes were concentrated in Tibet Autonomous Region (6.223 × 10 USD), Heilongjiang (5.810 × 10 USD), and Qinghai (5.500 × 10 USD). 2) Waste treatment and climate regulation services contributed to 26.29% and 24.74% respectively, of the total ecosystem service value of the marsh wetlands. Hydrological regulation and waste treatment contributed to 41.39% and 32.75%, respectively, of the total ecosystem service value of the lake wetlands. 3) The total ecological service value of the lake and marsh wetlands was 54.64% of the total service value of natural grassland ecosystems and 30.34% of the total service value of forests ecosystems in China. [ABSTRACT FROM AUTHOR]

The thermal-environment effect exists in the field of rapid urbanization. It has adverse effects on the urban atmosphere, regional climate, energy consumption, and public health. Shenzhen, a representative of rapidly urbanizing cities in China, was selected as a case for pattern dynamics analysis of the thermal environment. The surface temperature was acquired from the thermal infrared data of Landsat TM and ETM+ images in 1986, 1995, and 2005 by Jiménez-Muñoz and Sobrino's generalized single-channel method, which was used in assessing the distribution and spatial patterns of the thermal environment. The relative thermal environment curve (RTC) was combined with Moran's I analysis to assess the pattern dynamics of the thermal environment in different urbanization periods. Moran's I index and the RTC represent a process of aggregation-fragmentation-aggregation, which shows the aggregation pattern of a decrease during the rapid urbanization period and then an increase during the steady urbanization period. High-temperature areas gradually expanded to a uniform and scattered distribution in the rapid urbanization period; while the high thermal-environment effect was gradually transformed into a steady spatial pattern in the stable urbanization period. To characterize the increasing development in this multiple-center city, we chose profiles along an urban-development axis. The results suggest that heat islands have expanded from internal urban to external urban areas. Four profiles were obtained showing differences in shape due to spatial differences in the process of development. [ABSTRACT FROM AUTHOR]

China still use sketch maps as control devices that guarantees consistency and accuracy of population counting in previous census. Although the rapid advancement of geospatial technologies provides many possible solutions of digital census mapping, existing researches do not answer which solution is suitable to China. Subject to many constraints originated from characteristics of China, a practical solution of census mapping based on remote sensing imagery and auxiliary geographic information was proposed and proved to be feasible through evaluation analysis and a three-stage pilot study. Imagery with 2.5 meters and higher resolution, innovative workflow of census areas delineation, easy-to-use census mapping software packages and training organization all together provide the all-around supports for the 2010 rounded census (the 6th census) mapping activities. A digital census geographic framework detailed at the level of enumeration area was established in the 2010 rounded census which fills in the gaps in the field of modern geospatial census in China. The spatially referenced digital census database, especially the detailed census units, is of great value in successive census, sampling survey and many other census-related fields. Future work including quality evaluation of census areas, census mapping solution in the Tibet Autonomous Region are also discussed. [ABSTRACT FROM AUTHOR]

This study investigated the regional differences of China's urban land expansion from the late 1980s to the year of 2008, based on the spatio-temporal analysis of CLCD (China's land cover/land use database) datasets which were mainly produced from remote sensing imagery data. A newly defined urbanization level index (UI), based on urban land area, is proposed to describe Chinese urban expansion process at 1 kilometer, provincial, regional, and national scales, together with the absolute urban expansion index (UE) and the relative urbanization expansion index (UE). The results indicate that the percentages of total land area occupied by urban in the late 1980s, 1995, 2000, 2005, and 2008 were approximately 0.25%, 0.32%, 0.33%, 0.43% and 0.52% of China's total land area, respectively. Between the late 1980s and 2008, the total urban expansion in the mainland of China was 2.645 × 10 km, resulting in an annual urban expansion area of about 1322.7 km/yr, with the UE of 111.9%. This study also finds that there has been an obvious spatial gradient of urbanization ratio running from the east coast to the west inland, and the urbanization gaps among different regions have persisted over the past two decades. The study also reveals obvious temporal variations of the urbanization rates. There was very little urban growth during the period of 1995-2000 due to the governmental policy factors. [ABSTRACT FROM AUTHOR]

Wetlands play an important ecological role and provide many functions for people, yet wetlands are currently decreasing and deteriorating. The ability to calculate an economic value for the loss of wetlands is becoming increasingly important for policy makers. In this study, remote sensing, field investigations, department visits, and other methods were used to survey wetland types, assess wetland area changes, and calculate wetland economic value. Market value loss and ecological function value loss, caused by reduction of wetland area and environmental pollution were calculated using commonly accepted methods of market valuation, ecological valuation, environmental protection investment cost analysis, and outcome parameters. According to market value loss and ecological function value loss, preliminarily fund allocation for wetland and ecological compensation was calculated. This will provide an important reference for future Yellow River Delta eco-compensation studies. [ABSTRACT FROM AUTHOR]

In order to promote the application of Beijing-1 small satellite (BJ-1) remote sensing data, the multispectral and panchromatic images captured by BJ-1 were used for land cover classification in Pangzhuang Coal Mining. An improved Intensity-Hue-Saturation (IHS) fusion algorithm is proposed to fuse panchromatic and multispectral images, in which intensity component and panchromatic image are combined using the weights determined by edge pixels in the panchromatic image identified by grey absolute correlation degree. This improved IHS fusion algorithm outperforms traditional IHS fusion method to a certain extent, evidenced by its ability in preserving spectral information and enhancing spatial details. Dempster-Shafer (D-S) evidence theory was adopted to combine the outputs of three member classifiers to generate the final classification map with higher accuracy than that by any individual classifier. Based on this study, we conclude that Beijing-1 small satellite remote sensing images are useful to monitor and analyze land cover change and ecological environment degradation in mining areas, and the proposed fusion algorithms at data and decision levels can integrate the advantages of multi-resolution images and multiple classifiers, improve the overall accuracy and produce a more reliable land cover map. [ABSTRACT FROM AUTHOR]