The Experts below are selected from a list of 37701 Experts worldwide ranked by ideXlab platform
Xunming Wang - One of the best experts on this subject based on the ideXlab platform.
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Sandy Desertification: Borne on the wind
Chinese Science Bulletin, 2013Co-Authors: Xunming WangAbstract:Sandy Desertification is both an inherently interesting bioscience and geoscience topic and an important topic from the perspectives of the ecological environment and food security. It has therefore increasingly attracted the attention of the public, in addition to researchers, government officials, and international organizations. This paper reviews the development of knowledge on sandy Desertification, research progress in understanding the physical and biological processes involved in sandy Desertification, and the significance of wind activity in determining the increases and decreases in sandy Desertification. Based on this review of current research on the mechanisms and processes of sandy Desertification, combining geological and biological sciences appears likely to improve our understanding of this complex system, thereby providing a more holistic understanding of sandy Desertification at a range of temporal and spatial scales.
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responses of dune activity and Desertification in china to global warming in the twenty first century
Global and Planetary Change, 2009Co-Authors: Xunming Wang, Yi Yang, Zhibao Dong, Caixia ZhangAbstract:Abstract Most areas of arid and semiarid China are covered by aeolian sand dunes, sand sheets, and desert steppes, and the existence of the nearly 80 million people who live in this region could be seriously jeopardized if climate change increases Desertification. However, the expected trends in Desertification during the 21st century are poorly understood. In the present study, we selected the ECHAM4 and HadCM3 global climate models (after comparing them with the results of the GFDL-R30, CGCM2, and CSIRO-Mk2b models) and used simulations of a dune mobility index under IPCC SRES climate scenarios A1FI, A2a, A2b, A2c, B1a, B2a, and B2b to estimate future trends in dune activity and Desertification in China. Although uncertainties in climate predictions mean that there is still far to go before we can develop a comprehensive dune activity estimation system, HadCM3 simulations with most greenhouse forcing scenarios showed decreased Desertification in most western region of arid and semiarid China by 2039, but increased Desertification thereafter, whereas ECHAM4 simulation results showed that Desertification will increase during this period. Inhabitants of thecentral region will benefit from reversed Desertification from 2010 to 2099, whereas inhabitants of the eastern region will suffer from increased Desertification from 2010 to 2099. From 2010 to 2039, most regions will not be significantly affected by Desertification, but from 2040 to 2099, the environments of the western and eastern regions will deteriorate due to the significant effects of global warming (particularly the interaction between precipitation and potential evapotranspiration), leading to decreased livestock and grain yields and possibly threatening China's food security.
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Desertification in china an assessment
Earth-Science Reviews, 2008Co-Authors: Xunming Wang, Fahu Chen, Eerdun Hasi, Jinchang LiAbstract:Abstract Arid and semiarid China have experienced multiple arid phases throughout the Quaternary, and over the past five decades, there have been several periods with relatively high or low rates of Desertification and rehabilitation. The causes of these changes and their historical trends have been debated by scientists because of their potentially huge significance for China, as well as for the global ecology and food supply. This paper reviews recent studies of Desertification in different regions of arid and semiarid China. In general, the results of systematic monitoring, and analyses of the causes of Desertification and the contemporaneous human impacts, suggest that Desertification in China has been primarily caused by climate change, and particularly by strong wind regimes (with high sand transport potential) accompanied by decreased spring precipitation. Unfortunately, although numerous scientists have claimed that Desertification in China is primarily due to human impacts; there is surprisingly little unassailable evidence to support this claim. The review presented in this paper show that Desertification in China is likely to be controlled by climate change and geomorphological processes, even though human impacts have undeniably exacerbated their effects. Our arguments for both climate change and human activity as factors responsible for the observed changes in Desertification rely primarily on inferences based on correlations between trends, thus future research must seek stronger and more direct evidence for the causal relationships that we have proposed as possibilities. This improved information is essential to provide a firm basis for future policy decisions on how best to combat Desertification.
Xiao Song - One of the best experts on this subject based on the ideXlab platform.
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the dynamics of Desertification in the farming pastoral region of north china over the past 10 years and their relationship to climate change and human activity
Catena, 2014Co-Authors: Duanyang Xu, Chunlei Li, Xiao SongAbstract:Abstract The farming-pastoral region of North China is a region that has suffered from serious Desertification, and the multiple transitional characteristics in this region make it very difficult to link the progress of Desertification to the driving forces behind it. This paper mainly focuses on the dynamics of Desertification over the past 10 years and their relationship to climate change and human activity. According to the MODIS images in 2000 and 2010, the farming-pastoral region had experienced significant Desertification dynamics over the past 10 years. The area of regions that had undergone Desertification reversion and expansion were 186,240 km2 and 199,525 km2 respectively, and the spatial distribution of these regions showed great heterogeneity. The relationship between Desertification dynamics and their driving forces was investigated by comparing the change in the NPP that was induced by climate change and human activity for each pixel that experienced Desertification reversion and expansion. From 2000 to 2010, the coupling of climate change and human activity was the dominant factor behind Desertification reversion. However, the human activity was the dominant factor that controlled the Desertification expansion process between 2000 and 2010. The driving processes of Desertification also had considerable spatial heterogeneity, and the dominant factors behind Desertification reversion and expansion in each sub-region were not completely the same. So, the scale effect must be considered when explaining the results from similar studies.
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The Research of the Quantitative Method of Desertification Assessment at Large Scale Based on MODIS Data and Decision Tree Model - A Case Study in Farming-Pastoral Region of North China
2012 2nd International Conference on Remote Sensing Environment and Transportation Engineering, 2012Co-Authors: Duanyang Xu, Chunlei Li, Xiao SongAbstract:China is one of the countries that seriously suffered Desertification in the world, and it is very meaningful to develop a quantitative method to assess Desertification at large scale. In this study, the MODIS images were selected as the data resources, and NDVI, land surface albedo, soil water index (the reflectance of MODIS band 7) were selected as the indicators for assessing Desertification. Based on building the indicator rule sets of different Desertification grades in different sub-regions, the authors developed a quantitative method for Desertification assessment by using decision tree model. The results showed that, the method developed in this study that can reflect the heterogeneity of land surface at large scale, and the overall accuracy of the method can reach 85.5%, which was suitable to assess Desertification at large scale. Based on using this method to assess the Desertification in farming-pastoral region of north China in 2000 and 2010, the authors found that the areas of lands that experienced Desertification reversion and Desertification expansion were almost consistent, and the spatial distribution of these regions existed obvious differences.
Duanyang Xu - One of the best experts on this subject based on the ideXlab platform.
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the dynamics of Desertification in the farming pastoral region of north china over the past 10 years and their relationship to climate change and human activity
Catena, 2014Co-Authors: Duanyang Xu, Chunlei Li, Xiao SongAbstract:Abstract The farming-pastoral region of North China is a region that has suffered from serious Desertification, and the multiple transitional characteristics in this region make it very difficult to link the progress of Desertification to the driving forces behind it. This paper mainly focuses on the dynamics of Desertification over the past 10 years and their relationship to climate change and human activity. According to the MODIS images in 2000 and 2010, the farming-pastoral region had experienced significant Desertification dynamics over the past 10 years. The area of regions that had undergone Desertification reversion and expansion were 186,240 km2 and 199,525 km2 respectively, and the spatial distribution of these regions showed great heterogeneity. The relationship between Desertification dynamics and their driving forces was investigated by comparing the change in the NPP that was induced by climate change and human activity for each pixel that experienced Desertification reversion and expansion. From 2000 to 2010, the coupling of climate change and human activity was the dominant factor behind Desertification reversion. However, the human activity was the dominant factor that controlled the Desertification expansion process between 2000 and 2010. The driving processes of Desertification also had considerable spatial heterogeneity, and the dominant factors behind Desertification reversion and expansion in each sub-region were not completely the same. So, the scale effect must be considered when explaining the results from similar studies.
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The Research of the Quantitative Method of Desertification Assessment at Large Scale Based on MODIS Data and Decision Tree Model - A Case Study in Farming-Pastoral Region of North China
2012 2nd International Conference on Remote Sensing Environment and Transportation Engineering, 2012Co-Authors: Duanyang Xu, Chunlei Li, Xiao SongAbstract:China is one of the countries that seriously suffered Desertification in the world, and it is very meaningful to develop a quantitative method to assess Desertification at large scale. In this study, the MODIS images were selected as the data resources, and NDVI, land surface albedo, soil water index (the reflectance of MODIS band 7) were selected as the indicators for assessing Desertification. Based on building the indicator rule sets of different Desertification grades in different sub-regions, the authors developed a quantitative method for Desertification assessment by using decision tree model. The results showed that, the method developed in this study that can reflect the heterogeneity of land surface at large scale, and the overall accuracy of the method can reach 85.5%, which was suitable to assess Desertification at large scale. Based on using this method to assess the Desertification in farming-pastoral region of north China in 2000 and 2010, the authors found that the areas of lands that experienced Desertification reversion and Desertification expansion were almost consistent, and the spatial distribution of these regions existed obvious differences.
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multi scale quantitative assessment of the relative roles of climate change and human activities in Desertification a case study of the ordos plateau china
Journal of Arid Environments, 2010Co-Authors: Duanyang Xu, X W Kang, D F ZhuangAbstract:Abstract Multi-scale quantitative assessment of the relative role that climate change and human activities play in Desertification is an important approach to clarifying the causes of Desertification. In this study, a quantitative method was developed to assess the relative roles of climate change and human activities in Desertification by selecting NPP as an indicator. The potential NPP and the difference between the potential and actual NPP were used to represent the impacts of climate and human factors on Desertification. Based on this method, the relative roles that climate change and human activities play in Desertification reversion and expansion in the Ordos Plateau were assessed at different spatial–temporal scales. The results revealed that increasing the spatial scale resulted in the area of the primary Desertification process and its dominated driving process becoming more predominant at coarser scales from 1980 to 20000. For assessment at multi-temporal scales, climate change was the dominant factor inducing the Desertification reversion from 1980 to 1990; however, human activities controlled the Desertification reversion from 1990 to 2000 and 1980 to 2000. Assessment at longer temporal scales may average the characteristics when it is assessed at shorter scales. Therefore, scale-dependent characteristics must be considered when evaluating the causes of Desertification.
Chengzhang Zhao - One of the best experts on this subject based on the ideXlab platform.
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quantitative assessment of the individual contribution of climate and human factors to Desertification in northwest china using net primary productivity as an indicator
Ecological Indicators, 2015Co-Authors: Wei Zhou, Chengcheng Gang, Fuchun Zhou, Jianlong Li, Xiaogang Dong, Chengzhang ZhaoAbstract:Abstract An accurate quantitative assessment of the relative roles of climate change and human activities in Desertification is significant to understand the driving mechanisms deeply and control Desertification development. In this study, we selected net primary productivity (NPP) as an indicator to discriminate the relative roles of climate and human factors in Desertification during 2001–2010 in northwest China. The potential NPP and the difference between potential and actual NPPs were used to represent the impacts of climate change and human activities on Desertification. Desertification expanded on 55.8% of the study area, within which 70.3% of the Desertification expansion was caused by human activities compared with only 21.7% induced by climate change. On the contrary, 42.1% of Desertification reversion was caused by human activities and 48.4% resulted from climate changes. The NPP variation also could be calculated to assess the relative roles and showed that 69% of NPP decrease was caused by human impacts compared with 15.2% induced by climate change. By contrast, 23.9% of NPP increase was caused by climate change, whereas 54% resulted from human activities. In addition, the relative roles of two factors possessed great spatial heterogeneity in six provinces. We developed three propositions. First, the Desertification expansion was dominated by human activities, whereas Desertification reversion was dominated by climate change, as typified by Xinjiang, Qinghai, and Gansu. Second, both Desertification expansion and reversion were induced by human activities, as typified by the west of Inner Mongolia and Shaanxi. Third, climate change dominated the Desertification expansion in Ningxia province.
Li Baoguo - One of the best experts on this subject based on the ideXlab platform.
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agricultural causes of Desertification risk in minqin china
Journal of Environmental Management, 2006Co-Authors: Sun Danfeng, Richard Dawson, Li BaoguoAbstract:Abstract This study uses statistical modeling techniques to develop a Desertification risk index (RI) for Minqin County, Gansu Province, China. Twenty socio-economic factors were selected and compared with the RI results to explore the spatial and temporal variability of Desertification risk in the study area and to identify possible local driving forces behind Desertification risk. The explanatory factors were different in 1988, 1992 and 1997, possibly reflecting the role of temporal variation as a contributor to Desertification. The average number of sheep per-household was found to be an important indicator of change in Desertification risk, while changes in ridge crop planting area explained the distribution of the rate of change in Desertification risk in 1988–1992. The results suggests that the RI was useful in expanding the understanding of spatial temporal Desertification issues in Minqin County, as well as identifying a current set of agricultural activities related to Desertification risk. Further, given the limited nature of consistent data and observations for the area, development of the RI also served to establish a baseline for future investigations into Desertification change and the risks such change might pose for the region.