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Liu J.-H.,Chinese Research Academy of Environmental Sciences | Gao J.-X.,Technology and Standards | Lv S.-H.,Chinese Research Academy of Environmental Sciences | Han Y.-W.,Chinese Research Academy of Environmental Sciences | Nie Y.-H.,Satellite Environment Center
Journal of Arid Environments | Year: 2011

Meteorological records show a rise in temperature and decrease in precipitation in most parts of the farming-pastoral ecotone of Northern China over the last 50 years. During the last quarter of the 20th Century, the agrarian sector went through a series of reforms and changes in government policies on land use that have led to extensive changes in land cover. The objective of this study was to redefine the location and analyze the boundary variations under the effects of climate and land use changes in the farming-pastoral ecotone of Northern China. The results showed that the location of study area has been redefined as both a climatic ecotone from the perspective of suitability of precipitation and temperature for agricultural crops and vegetation growth, and also a land use ecotone based on the impacts of farmland restructuring by government policies on land use. In recent decades, the climatic boundary has moved southeast while the land use boundary has moved northwest, showing opposing directions of change. The extent of boundary changes in the northeast and northern sections are far greater than in the northwestern section of the farming-pastoral ecotone of Northern China. © 2010 Elsevier Ltd. Source


Ouyang W.,Beijing Normal University | Xu Y.,Beijing Normal University | Hao F.,Beijing Normal University | Wang X.,Satellite Environment Center | And 2 more authors.
Catena | Year: 2013

The cultivation patterns in the Sanjiang Plain of Northeast China have changed over the last three decades, resulting in variations in the land use and soil properties. Changes in cultivation patterns are an important concern for agricultural development in China. In order to highlight the impact of long-term land use on soil quality, the spatial pattern of permanent wetland, permanent forest, permanent dryland, wetland converted to dryland, wetland converted to paddy land, dryland converted to paddy land, and forest converted to dryland in the Sanjiang Plain from 1979 to 2009 was identified. Forty-one soil samples from these seven permanent and converted land use types were collected and eight indexes were analysed. The soil nutrient content of permanent forest, dryland reclaimed from forest, permanent wetland and dryland reclaimed from wetland was not significantly different. However, the soil nutrient content of permanent wetland, except for the available phosphorus, was higher than those of dryland and paddy land reclaimed from wetland. Compared to the permanent wetland, the soil organic matter and total nitrogen of dryland reclaimed from wetland decreased by 55.8% and 59.6%, respectively. For paddy land reclaimed from wetland, the decline in soil organic matter and total nitrogen was 63.6% and 67.6%, respectively. However, the total potassium and available phosphorus of permanent wetland were significantly lower than the amounts in dryland. After permanent forest and wetland were changed to dryland, the available phosphorus increased by 107.7% and 103.2%, respectively. The one-way ANOVA was applied to assess the effect of different changes in land use patterns on the soil nutrient contents. This study suggests that the reclamation of wetland decreased soil nutrient content, but the conversion of dryland to paddy land and forest to paddy land increased the nutrient content. The findings can provide advice for agricultural land use managers and also enhance the understanding of nutrient balance. © 2012 Elsevier B.V. Source


Zhang Y.,NavInfo Co. | Zhang Y.,Satellite Environment Center | Fung T.,Chinese University of Hong Kong
Environment and Planning B: Planning and Design | Year: 2013

On the basis of the principle of sustainable development, land-use planning often requires a compromise between economic development and environmental conservation with social justice advocated. Given that values, perceptions, and ideas vary among stakeholders, land-use planning often involves a variety of conflicts with advocating public participation. In this paper we focus on extending the decision-support capabilities of public participation GIS (PPGIS) to facilitate conflict resolution. In the proposed model, conflicts are designated to be investigated and resolved from two levels, namely the value level and the specifics level. From the value level, a consensus-building process is proposed to help participants promote mutual understanding and achieve group agreement. At the specifics level, participants are asked to search for compromise space through discussions over particular concerns. The ultimate goal of the model is to help participants to work out the most acceptable land-use plan. Moreover, a PPGIS prototype with the conflict resolution model was designed and implemented in the context of Lantau Island, Hong Kong. The study could contribute to PPGIS research and land-use planning by developing the methodology of conflict resolution. The challenges that we encountered and some future directions are also covered in the paper. Source


Wang Q.,Satellite Environment Center
International Journal of Digital Earth | Year: 2012

The Chinese Government attaches great importance to applications of satellite remote sensing in environmental monitoring. On 6 September 2008, the first two satellites of the Environment and Disaster Monitoring and Prediction Satellite Constellation (HJ), HJ-1A and HJ-1B, were successfully launched, which started a new era of satellite applications for environmental monitoring in China. An introduction to the satellite, instrument, and ground systems of HJ-1A and HJ-1B is presented in this article, and an analysis of their technical performance and characteristics is also given. Focusing on the operational needs of environmental monitoring in China, the general design, functional construction, and operational mode of the application system of HJ-1A and HJ-1B are detailed, and the operations and applications of the two satellites are also discussed. © 2012 Taylor and Francis Group, LLC. Source


Gao Y.,Satellite Environment Center | Gao Y.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Wang Q.,Satellite Environment Center | Wang C.,Satellite Environment Center | And 4 more authors.
Science of the Total Environment | Year: 2013

Alpine ecosystems are highly sensitive to global climate changes. The Tibetan Plateau is one of the areas that are most sensitive to global climate change. Increases in temperature and changes in precipitation can impact the plateau's ecosystem productivity. Net primary productivity (NPP) is one of the most important factors in the carbon cycle of terrestrial ecosystems. In this paper, a light-use-efficiency model was used to estimate the net primary productivity in the Tibetan Plateau. The model is based on a 1-km×1-km-resolution map of vegetation type, multi-temporal 500-m-resolution MODIS data and daily meteorological data. The spatial distribution pattern and dynamic change of the annual NPP from 2001 to 2008 are analyzed. Then, we analyzed the response of the NPP to temperature and precipitation changes. The results show that the mean annual NPP of alpine ecosystems in the Tibetan Plateau is equal to 0.472 Pg C and that the NPP exhibits significant seasonal and interannual variation due to the combined effects of temperature and precipitation changes. Finally, to analyze the effect of temperature and precipitation on the inter-annual change of the NPP, the correlation coefficient between temperature, precipitation and the NPP was computed. It was found that the relations among air temperature, precipitation and the NPP in the Tibetan Plateau region are different. The annual average temperature increase had a significantly positive effect on the vegetation NPP (R2=0.83). In contrast, the annual precipitation changes had a weakly negative effect on the vegetation NPP (R2=0.373). © 2012 Elsevier B.V. Source

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