Poyang Lake is the largest shallow lake wetlands in China, and which vegetation succession is rapid under high
changeable hydrological regimes. This study measured the fluxes of carbon dioxide and methane simultaneously by
opaque static chamber-gas chromatography technique for typical wetland vegetation ecosystems in the growing season.
In view of the advantages both in temporal and spatial, HJ-1 satellite images were chosen as the data source for
vegetation cover classification and area estimates. And based on the areas in different vegetation, carbon flux for the
entire study area was estimated during the growing season. Results indicated that carbon dioxide flux has closer
relationship with vegetation change than methane flux does.
Methane (CH4), a significant atmospheric trace-gas, controls numerous chemical processes and species in the
troposphere and stratosphere and is also a strong greenhouse gas with significantly adverse environmental impacts. Since
the SCIAMACHY on the Envisat was in orbit since 2002, CH4 measurements at a regional scale became available. This
study (1) firstly improved the spatial resolution of 0.5°×0.5° lat/lon grid data provided by University of Bremen IUP/IFE
SCIAMACHY near-infrared nadir measurements using the scientific retrieval algorithm WFM-DOAS to 0.1°×0.1°
lat/lon with the ordinary Kriging method, (2) then analyzed the spatial-temporal characteristics of atmospheric CH4
concentration in the Yangtze River basin (YRB), China from 2003 to 2005, (3) finally analyzed the relations with the
main environmental factors: the precipitation from GSMaP MVK+ 0.1x 0.1 lat/lon degree grid data and the temperature
from 147 meteorological stations in the YRB. The analysis shows that atmospheric methane concentration has significant
and obvious characteristics of the spatial distribution of the inter-annual cycle fluctuations and seasonal characteristics
during the year, and points out that the temperature is the main impact factor.
Tibetan Plateau serves as the sources of several big rivers such as Yangtze River and Yellow River. Due to the high
elevation of the plateau, it has profound thermal and dynamical influence on both local and global climate and
atmospheric circulation. Land surface temperature (LST) plays a significant role in climate change and glacier melting.
In this paper we present our study on mapping land surface temperature variations for the years 2005-2006 in the plateau
using MODIS satellite data. Since the plateau has a very rough ground surface that is difficult to estimate the necessary
parameters for the mapping, we have developed a practical approach for LST retrieval from the MODIS thermal band
data. The approach was alternated from the split window algorithm proposed by Qin et al. (2001) for NOAA-AVHRR
data. Detailed methods for atmospheric transmittance and ground emissivity have been presented in the paper. Results
from our study indicate that ground temperature in the plateau is featured with obvious spatial and temporal variations.
Generally the temperature in winter and spring is less than 0°C and it is also not very high in summer, due to the high
altitude. Because of topological form, Chaidamu Basin of the plateau has the highest temperature in summer, usually
high up to above 40°C. Our study provides an alternative to understand the environmental changes in the plateau that
shape significant impacts on atmospheric dynamics of East Asia and South Asia.
As an important pasture region, Tibet has about 82 million hectares of natural grassland, accounting for 68.11% of its
total territory. Above 90% of Tibetan grassland belongs to the types of alpine meadow steppe and alpine steppe with
highly nutritious forage plant. Animal husbandry constitutes a major part of agricultural economy in Tibet. It is believed
that snow disaster become a significant threat to the development of animal husbandry in Tibet. The disaster often
happens in winter and spring as a result of complicated mountainous features and mutable climatic conditions. Statistics
indicates that, on average, there is a slight snow disaster for each 3-year, a medium disaster within 5 to 6 years, and a big
disaster in 8-10 years. Large numbers of animals died of hungry and cold during the disaster period. Huge economic loss
due to the disaster had brought giant difficulties to local herdsmen in Tibet. Accurate and timely monitoring of snow
cover for snow disaster evaluating is very important to provide the required information for decision-making in
anti-disaster campaigns. Remote sensing has many advantages in snow disaster monitoring hence been extensively
applied as the main approach for snow cover monitoring. In this paper we present our study of snow cover monitoring
and snow disaster evaluating in Tibet. An applicable approach has been developed in the study for the monitoring and
evaluating. The approach is based on the normalize difference of snow index (NDSI) and DEM retrieved from MODIS
and GIS data. Using the approach, we analyzed the snowstorm occurring in mid-March 2007 in southern Tibet. Results
from our analysis indicated that the new approach is able to provide an accurate estimate of snow cover area and snow
depth in southern Tibet. Thus we may conclude that the approach can be used as an efficient alternative for snow cover
monitoring and snow disaster evaluating in Tibet.
North China Plain was the most important cropping region in China with severe challenges of water shortage. Cropping
in the plain required large amount of irrigation water to support harvest. However, water resource was very limited due
to high evaporation and unbalanced precipitation. Both surface and underground water resources in the region had been
over-extracted. Since agriculture consists of the largest component of water uses, mapping irrigation area for estimation
of agricultural water demand was urgently required to improve the administration of water resource for effective
utilization in the region. We presented our systematic investigation of mapping the irrigation area in the plain using
MODIS remote sensing data. Winter wheat had been identified as the main cropping systems requiring intensive
irrigation during the growing season from March to early June. The normalized difference of vegetation index (NDVI)
had been used to identify winter wheat and forest, which could then be used as the input for irrigation mapping. Then
Vegetation supply water index (VSWI) had been used for identifying irrigated area in winter wheat field, which
combined the information of temperature and growing condition of vegetation together. According to our study in North
China plain, irrigation area could be properly mapped for estimation of agricultural water demand using the MODIS
data. Total irrigation area of the region was about 5.9 million ha in 2006. The results indicated that the spatial variation
of irrigation area was very obvious in the region. More intensive irrigation could be observed in southern Hebei and
northeast Henan of the region. Irrigation percentage in these areas might reach up to 70% for winter wheat in 2006.
Therefore, our study demonstrated that MODIS data could be useful for irrigation mapping in regional scale.
Snow is the most important freshwater resource in northern Xinjiang, which is a typical inland arid ecosystem in western
China. Snow mapping can provide useful information for water resource management in this arid ecosystem. An
applicable approach for snow mapping in Northern Xinjiang Basin using MODIS data was proposed in this paper. The
approach of linear spectral mixture analysis (LSMA) was used to calculate snow cover fractions within a pixel, which
was used to establish a regression function with NDSI at a 250-meter grid resolution. Field campaigns were conducted to
examine whether NDSI can be used to extend the utility of the snow mapping approach to obtain sub-pixel estimates of
snow cover. In addition, snow depths at 80 sampling sites were collected in the study region. The correlation between
image reflectivity and snow depth as well as the comparison between measured snow spectra and image spectra were
analyzed. An algorithm was developed on the basis of the correlation for snow depth mapping in the region. Validation
for another dataset with 50 sampling sites showed an RMSE of 1.63, indicating that the algorithm was able to provide an
estimation of snow depth at an accuracy of 1.63cm. The results indicated that snow cover area can reach 81% and
average snow depth was 13.8 cm in north Xinjiang in January 2005. Generally speaking, the snow cover and depth had a
trend of gradually decreasing from north to south and from the surroundings to the center. Temporally, the cover reached
a maximum in early January, and the depth reached a maximum was ten days later. Snow duration was so different in
different regions with the Aletai region having the longest and the Bole having the shortest. In the period of snow
melting, snow depth decreased earlier, afterward snow cover dwindled. Our study showed that the spatial and temporal
variation of snow cover was very critical for water resource management in the arid inland region and MODIS satellite
data provide an alternative for snow mapping through dedicated development of mapping algorithms suitable for local
application.
Grassland ecosystem degradation and desertification has been highly concerned in China for years because such
degradation is perceived to directly relate with the occurrence of sandstorms invading into north China. In this study we
intend to map the spatial-temporal variation of vegetation cover density from remote sensing data in Hulun Buir, a
typical grassland ecosystem with the highest biomass productivity in Inner Mongolia of China. Since NDVI is a good
indicator of vegetation, a practical approach had been developed in the study to map the spatial-temporal variation of the
vegetation cover. The MODIS satellite data were used for the mapping. Results from our study indicated that the
vegetation cover rate had been steadily decreasing in recent years, with relatively high spatial and temporal variation.
Our study reveals that the rate on average has a trend of steadily decreasing in recent years. In 2000 the rate was above
80.6% on average, while it decreased to below 76.5% in 2006. Generally the west part of the region had much lower
vegetation cover rate than the east part, probably due to the fact that the east part was dominated with forest ecosystem
while the west part with fragile grassland. The counties of Xinbaerhuyou Banner and Manzhouli in the west part had the
lowest vegetation cover rate among the 13 counties. As to the grassland types, lowland meadow had the highest
vegetation cover rate while the temperate meadow and steppe had the lowest, indicating that ecosystem degradation was
very serious in the temperate meadow and steppe, which were mainly distributed in the west part of the region. Though
many factors might contribute to the decrease of vegetation cover, annual precipitation vibration had very good
correspondence with the up-and-down change of vegetation cover in the region. In addition, overgrazing also played an
important role in accelerating the degradation under the drought year. Therefore, we were able to conclude that the
grassland ecosystem in Hulun Buir was under a very serious situation of degradation and desertification. Our study
suggested that the change of vegetation cover rate could be an applicable indicator for grassland ecosystem monitoring
required urgently to combat grassland degradation and desertification in arid and semiarid region.
A paddy rice ecosystem is a farming system composed of paddy, animals, microbes and other environmental factors in
specific time and space, with particular temporal and spatial dynamics. Since paddy rice is a main grain crop to feed
above half of population in China, the performance of paddy rice ecosystem is highly concerned to yield level of paddy
and food supply safety in China. Therefore, monitoring the performance of paddy rice ecosystem is very important to
obtain the required information for evaluation of ecosystem health. In the study we intend to develop an approach to
monitor the ecosystem performance spatially and dynamically in a regional scale using MODIS remote sensing data and
GIS spatial mapping. On the basis of key factors governing the paddy rice ecosystem, we accordingly develop the
following three indicators for the evaluation: Crop growing index (CGI), environmental Index (EI), and pests-diseases
index (PDI). Then, we integrated the three indicators into a model with different weight coefficients to calculate
Comprehensive ecosystem health index (CEHI) to evaluate the performance and functioning of paddy rice ecosystem in
a regional scale. CGI indicates the health status of paddy rice calculated from the normalizing enhanced vegetation Index
(EVI) retrieved from MODIS data. EI is estimated from temperature Index (TI) and precipitation Index (PI) indicating
heat and water stress on the rice field. PDI reflects the damage brought by pests and diseases, which can be estimated
using the information obtained from governmental websites. Applying the approach to Lower Yangtze River Plain, we
monitor and evaluate the performance of paddy rice ecosystem in various stages of rice growing period in 2006. The
results indicated that the performance of the ecosystem was generally very encouraging. During booting stage and
heading and blooming stage, the health level was the highest in Anhui province, which is the main paddy rice producer
in the region. During stage of yellow ripeness, Jiangsu province had the lowest level of performance. Yield level of
paddy rice in 2006 confirms that the applicability of the proposed approach for a rapid evaluation and monitoring of
agricultural ecosystem performance in Lower Yangtze River Plain. As a result, the new approach could supply scientific
basis for relevant departments taking policies and measures to make sure stable development of paddy yield.
Based on Landsat MSS/TM images and CBERS-02 CCD data of Beitun Oasis in Ertix River Watershed in the years of
1972, 1989, 1999 and 2005, the landscape patterns for the past 30 years were analyzed. Using the GIS data collective
platform, we calculated the landscape pattern conversion probability matrix, landscape pattern index, and contribution
rates of major landscape components to characterize the impacts and responses of landscape pattern changes and
landscape ecological processes. The results indicate that in this region the areas of farmlands, urban & rural residential
lands and waters are increasing, the area of woodlands is decreasing, and that of grasslands is decreasing and then
increasing. In the desert landscape patterns, the areas of sandlands and Gobi deserts & bare lands are decreasing after
increasing, and those of saline or alkaline lands & marchlands are increasing obviously in the latter period. The features
of landscape ecological process of urban & rural residential lands are concentrated in spatial pattern, but for grasslands
and woodlands, those are fragmentized in spatial patterns. The landscape components convert very frequently, and the
landscape pattern is not stable. Woodlands ecosystem function reducing and soil salinization and alkalization result in a
negative influence on the local ecological system. It is essential to adjust the landscape patterns to rehabilitate and
construct the fragile ecological system of modern oasis landscape ecosystem in arid area and use water resources
reasonably, so that ecological environment and social economy is healthy and stable with sustainable development.
Land use/cover change (LUCC) has significant impacts on regional environment. Land surface temperature (LST) is an
important indicator for assessment of regional environment especially in big cities where urban heat island is very
obvious. In this study, remote sensing and geographic information systems (GIS) were used to detect LUCC for
assessment of its impacts on spatial variation of LST in Urumqi, a big city in northwestern China. Two Landsat
TM/ETM+ images respectively in 1987 and 2002 were examined for LUCC detection. LST and NDVI were computed
from the images for different land use/cover types. Impacts of LUCC on regional environment can be assessment
through LST difference during the period. Our results showed that land use/cover changes were very obvious in Urumqi
between 1987 and 2002 due to rapid expansion of the city. Urban/built-up land increased by almost twice in the period,
while the barren land, the forestland and water area declined. The increase of urban/built-up land was mainly from the
barren land. Spatial distribution of LST in the city has been highly altered as a result of urban expansion. The
urban/built-up area had LST increase by 4.48% during the period. The LST difference between built-up land and other
land use/cover types also significantly increased between 1978 and 2002, with high LST increase area corresponding to
the urban expansion regions. Moreover, changes of vegetation also had shaped many impacts on spatial variation of LST
in the city. We found that NDVI has a negative correlation with LST among the land use/cover types. This probably is
due to the ecological function of vegetation in cooling down the surface from high evapotranspiration. The study
demonstrated that combination of remote sensing and GIS provided an efficient way to examine LUCC for assessment of
its impacts on regional environment in big cities.
Grassland degradation in grassland ecosystems of China has been highly concerned in recent decades. Grassland growing is an important element for identification of grassland degradation. In this paper we intend to develop an applicable method for grassland growing monitoring in China using the EOS/MODIS data. Firstly the normalized difference of vegetation index (NDVI) can be calculated from April to October within grassland growing period in 2005 and 2006. In order to evaluate the grassland growing, vegetation index R was proposed, which was calculated from the NDVI value difference of the two years 2006 and 2005. According to the R value, five grades (from grade1 to grade5) were obtained: worse, slightly worse, balance, slightly better and better. Grassland region in China can be divided into a number of small sub-regions for determination of different regions and grassland types. Our results indicate that grassland growing was better in 2006 than in 2005. The grassland with balance, slight better and better growing accounted for 71.43% of the total grassland area, the area is 251.42 thousand KM2. The overall growing of 2006 is: Grade3>Grade4>Grade2>Grade5>Grade1.Valuation of the grassland growing is thus urgently required for better administration of the grassland ecosystem for sustainable development.
Drought is very severe in North China Plain, where winter wheat is one of the most important cropping systems. In this paper, we present an approach to map drought status of winter wheat in the plain for better farming management. The approach is based on the temperature-vegetation dryness index (TVDI) computed from the wet and dry edges of Ts-NDVI space. Using the MODIS data, we applied the approach to map drought status in North China Plain for the winter wheat growing period from March to May in 2006. Our results show that spatial variation of agricultural drought is very obvious in the region. Severe drought was observed in eastern Hebei, western Shandong, and northwestern Henan province respectively. The weather reports from China Meteorological Administration were used to validate our mapping results of the drought status. The highly accordance of our drought mapping results with the reported drought distribution from CMA confirms the applicability of TVDI approach in drought mapping in North China Plain.
Based on MODIS data of Shanghai City from 2003 to 2005, land surface temperature (LST) was retrieved and used
indirectly to get the quarterly intensity and higher temperature area of urban heat island. Results show that (1) the mean
highest LST is 13.9°C in winter and 32.5°C, 45.7°C and 29.0°C in spring, summer, and autumn, respectively; (2) the
relatively higher LST area distribution has obvious seasonal variation, which moves southeast in winter, northwest in
spring and summer, and draws back southeast again in autumn; (3) weak urban cold island exists in urban areas during
winter mornings; urban heat island exists in spring, summer and autumn; the summer's heat island is the most notable; and
(4) LST of urban cold island centre in winter morning is 2.6°C lower than that of countryside and the mean urban heat
island intensity is 5.7°C, 10.4°C and 4.2°C in spring, summer and autumn, respectively.
Hulun Buir represents the best grassland in Inner Mongolia. Due to intensive anthropogenic activities especially unreasonable grazing, desertification has been an important environmental problem in the grassland. In the paper we intend to develop an applicable approach for desertification monitoring in the grassland. Since vegetation is the most essential factor of grassland and desertification actually implies the declination of vegetation in the grassland, an index indication desertification severity has been constructed from vegetation cover fraction. Using MODIS satellite data, we firstly computed NDVI and then computed vegetation cover rate in the grassland. The rate is consequently used to construct the desertification index (DI) for evaluation of desertification severity. Using precipitation and temperature data from 45 points, we validate the capability of DI in representing the severity of actual desertification in the grassland. The general accordance of precipitation and temperature with DI demonstrates the applicability of the proposed approach for desertification in the grassland. Using the approach, we analyzed the changes of desertification in the grassland in recent years. Results showed that desertification process in the grassland are accelerating in recent years, with rate of 1% annually. The acceleration of desertification implies that grassland ecosystem is under evolution of degradation in spite of rapid economic development in the region. Our study suggests that necessary measures should be urgently employed to protect the grassland from further desertification.
Rangeland in Inner Mongolia is an arid ecosystem with vulnerability. Anthropogenic activities especially over-grazing
have been believed to be a leading factor shifting the vulnerability into actual degradation in the ecosystem. Net primary
productivity (NPP) is an important indicator for vulnerability monitoring in arid ecosystem. In this study we use the
vegetation photosynthesis model to estimate NPP of rangeland ecosystem in Inner Mongolia. The objective is to examine
the spatial variation of NPP in Inner Mongolia and to highlight vulnerable areas for sustainable development. Several
improvements have been done to the model especially in its parameterization. Land surface temperature required by the
model was estimated from split window algorithm proposed for MODIS thermal band data. Using the MODIS image
data and the ground climate datasets, we applied the improved model to estimate the NPP in 2003 in Inner Mongolia.
Our results showed that mean NPP was 192.03gC m-2 Gr-1 in Inner Mongolia in 2003. Spatial variation of the NPP was
very obvious. Very low NPP was observed in the western parts while relatively high NPP could be seen in the eastern
and northeastern parts. For various type rangelands, temperate alpine meadow is the highest. Although the mean NPP of
temperate steppe is not high, its area is the largest in Inner Mongolia, so it has the highest ratio to total NPP. Comparison
of our NPP with similar studies from conventional methods confirms the accuracy of our estimation.
High spatial resolution ASTER data have 5 thermal bands, of which band 13 and 14 are especially suitable for land surface temperature (LST) estimation. Generally, LST retrieval from two thermal bands is done through so-called split window technique. In the past two decades above 17 split window algorithms have been proposed. However, such algorithm for ASTER data has not been reported, probably due to the new availability of the data for environmental application. In the study, a new split window algorithm has been developed for LST retrieval from ASTER data. Our algorithm only involves two essential parameters for LST retrieval while keeping the same accuracy as those having more parameters. Detailed derivation of the split window algorithm has been given in the paper, which including formulation of thermal radiation transfer equation, determination of algorithm constants, and estimation of the essential parameters. Comparison of our algorithm with the existing ones for validation of its accuracy and applicability in the real world indicates that our algorithm has an average root mean square (RMS) error of 0.67°C when transmittance has an error of 0.05 and emissivity has an error of 0.01. Thus we can conclude that our algorithm is a very good alternative for accurate LST retrieval from ASTER data. Application of the algorithm to Wuxi-Suchou region in Yangtze River Delta produces a very reseasonable LST image of the region, hence confirms the applicability of the algorithm.
Sangong waddi basin in the north piedmont of Tianshan Mountains is a typical inland arid ecosystem in China. Desert environment especially land cover and land use in the basin changes dramatically in recent decades under the anthropogenic impacts. In order to develop an approach to highlight the environmental changes, we present a case study in the paper to examine the effects of different vegetation indices to the spatial changes of desert environment in the basin using Moderate-resolution Imaging Spectroradiometer (MODIS) data. First we compute the different vegetation indices including Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) for the basin from MODIS data and then compare their applicability to indicate the seasonal changes and spatial variation of vegetation in the basin. The results show that when the two vegetation index EVI and NDVI were used at the same time in monitoring the desert vegetation situation, Smaller the difference value between their values were, less the human activities interfere. The vegetation gradient variation of the desert vegetation is distinct in the basin. Therefore EVI can be used to highlight vegetation growth over the alluvial fans while NDVI is suitable to monitor vegetation growth in the hilly regions. With this finding, we further develop an approach to examine the desert environment changes in the basin. Based on the examination, several policy recommendations have been proposed in the study for better administration and utilization of arid land resources in the basin.
Soil moisture is one of the most important indicators for agricultural drought monitoring. In this paper we present a comprehensive review to the progress in remote sensing of soil moisture, with focus on discussion of the method details and problems existing in soil moisture estimation from remote sensing data. Thermal inertia and crop water stress index (CWSI) can be used for soil moisture estimation under bare soil and vegetable environments respectively. Anomaly vegetation index (AVI) and vegetation condition index (VCI) are another alternative methods for soil moisture estimation with Normalized difference vegetation index (NDVI). Both NDVI and land surface temperature (LST) are considered in temperature vegetation index (TVI), vegetation supply water index (VSWI) and vegetation temperature condition index (VTCI). Microwave remote sensing is the most effective technique for soil moisture estimation. Active microwave can provide high spatial resolution but is sensitive to soil rough and vegetation. Passive microwave has a low resolution and revisit frequency but it has more potential for large scale agricultural drought monitoring. Integration of optical/ IR and microwave remote sensing may be the practical method for drought monitoring in both accuracy and in efficiency.
KEYWORDS: Ecosystems, Solar radiation models, Data modeling, Remote sensing, Vegetation, MODIS, Process modeling, Solar radiation, Digital filtering, Climatology
Several sandstorms invading the capital of China in recent years cause many concerns to the issues of grassland ecosystem degradation in arid and semiarid grassland region of north China. Actually the degradation can be viewed as the decrease of primary productivity in the grassland. This provides the possibility to monitoring the degradation using satellite remote sensing technology. In the study we present our experiences in conducting the monitoring of grassland ecosystem degradation in north China. Using the EOS/MODIS data, we develop an applicable method for the monitoring on the basis of net primary productivity (NPP). We assume that there is always a turf without degradation in the area of the same hydrothermal condition and type of grassland. We then use the NPP of the turf to determine the level of degradation in this area. The grassland region in north China can be divided into a number of small sub-regions for the determination and the division of sub-regions can be done according to the types of grassland. As far as every sub-region is concerned, we take the max NPP as the base line to determine the degradation of other pixels in the sub-region. The degradation can be graded into five levels: serious degradation, high degradation, medium degradation, light degradation and non-degradation. Finally we apply the method to analyze the spatial characteristics of grassland degradation in north China in the year 2005. The results show that the situation of grassland degradation in north China is very serious. 95.57% of the grassland in north China has suffered from deterioration to various levels, among which serious degradation, high degradation, medium degradation and light degradation account for 41.06%, 33.52%, 11.72% and 9.28% of the total, respectively.
Landsat TM has a thermal band (TM6) operating in 10.45-12.6mm, which can be used for land surface temperature (LST) retrieval. Land surface emissivity (LSE) is an essential parameter for LST retrieval. However, LSE information is generally no available for many applications. In this paper we intend to develop an applicable approach for LSE estimation so that LST can be retrieved from Landsat TM6 data. Spatial resolution of TM6 is 120m under nadir. Pixels under this scale can be viewed as composed of three land cover patterns for most natural surfaces: vegetation, bare soil/rock and water. Emissivities of these land cover patterns are relatively stable and well known, which enables us to propose a method for LSE estimation using the visible and near infrared (NIR) bands. The composition ratio of vegetation and bare soil or building under pixel scale can be estimated from bands 3 and 4 (TM3 and TM4). LSE for TM6 can then be estimated through thermal radiance equation with the composition ratio and the emissivities of the patterns known. The proposed methodology for LSE estimation is simple and easy to use, hence provides opportunity to promote the application of TM6 data to agriculture and environments. Finally we apply this methodology to Lingxian region of Shangdong Province in North China Plain, the most important agricultural region in China, for LSE estimation and LST retrieval, which has produced a reasonable estimation of thermal variation of the region.
Rangeland ecosystems play important roles in both economic development and ecological service in China. The ecosystems are facing challenges of degradation in recent decades due to heavy population pressure and overgrazing. Valuation of the ecosystem degradation is thus urgently required for better administration of the rangeland ecosystem for sustainable development. An approach was developed to use remote sensing technology for valuation of rangeland ecosystem degradation in the paper. A model has been improved from the conventional method for the valuation. Parameterization of the model is retrieved from MODIS data hence featured with spatiality, which is required for the valuation. The model is then applied to MODIS data for the period between 2003 and 2005. Results indicate that the total degradation in Chinese rangeland ecosystem can be valued as 6660.3 million US dollars. The degradation can be evaluated into several categories according to the amount per square kilometer. Slight degradation with a value of 0~1000 US$ • km-2 accounts for ~1/4 of the total rangeland area in China. Severe degradation with a value of 1000~3000 US$ • km-2 accounts for ~1/3 of the total rangeland area. This indicates that the degradation is very common in the ecosystems. In spatial distribution, Inner Mongolia, Xinjiang, Tibet, Qinghai, Gansu, Yunnan and Sichuan are the main provinces with rangeland ecosystems, hence become the main contributors to the degradation. Inner Mongolia has the greatest degradation value among the provinces. Its degradation value accounts for 25.89% of the entire China. The seven provinces in the west have a degradation value of 5221.9 million US dollars, accounting for 78.41%.
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