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IEEE International Geoscience and Remote Sensing Symposium

作者： Wei Cao Lulu Liu Dan Wu Zhai Jun Yunfeng Hu Duanyang Xu Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research Beijing CAS China School of Architecture and Civil Engineering Chengdu University Chengdu China Ministry of Environmental Protection Nanjing Institute of Environmental Sciences Nanjing China Ministry of Environmental Protection Satellite Environment Center Beijing China

In this study, the Revised Universal Soil Loss Equation (RUSLE) was applied to analyze the spatial and temporal dynamics of soil erosion in North-South Pan River watershed from 2000 to 2010, and the driving factors were discussed. The results showed that: (1) The average annual soil loss per area in North-South Pan River watershed was 14.6 t/hm~2/yr from 2000 to 2010, and the mean annual total soil loss was about 118 million tons. (2) In 2000-2010, the soil erosion showed an obvious decreasing trend with an annual variation of -0.87 t/hm~2/yr in North-South Pan River watershed. The soil erosion decreased in 75.1% of this watershed, and the soil erosion intensity decreased in 23.6% of this watershed which were mainly changed from slight to trivial (10.0%), from moderate to slight (7.7%) and from intensive to moderate (2.9%). (3) The declining of soil erosion in North-South Pan River watershed was mainly caused by the joint effect of climate change and ecological projects. The rainfall erosivity factor decreased greatly according to the observations of meteorological stations. Meanwhile the implementation of ecological projects helped the restoration of forest and grassland, and the vegetation coverage raise greatly with 0.35%/yr increase which can better prevent the occurrence of soil erosion. (4) Though the soil erosion have decreased a lot recently, the ecological environment of North-south Pan River watershed is still extremely vulnerable to further curb the occurrence of soil erosion in this watershed, a long-term mechanism of ecological protection needs to be established.

关键词： Soil Rivers Forestry Vegetation Mathematical model Market research Vegetation mapping

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Global daily CO2 emissions for the year 2020

arXiv

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arXiv 2021年

作者： Liu, Zhu Deng, Zhu Ciais, Philippe Tan, Jianguang Zhu, Biqing Davis, Steven J. Andrew, Robbie Boucher, Olivier Arous, Simon Ben Canadell, Pep Dou, Xinyu Friedlingstein, Pierre Gentine, Pierre Guo, Rui Hong, Chaopeng Jackson, Robert B. Kammen, Daniel M. Ke, Piyu Le Quere, Corinne Monica, Crippa Janssens-Maenhout, Greet Peters, Glen Tanaka, Katsumasa Wang, Yilong Zheng, Bo Zhong, Haiwang Sun, Taochun Schellnhuber, Hans Joachim Department of Earth System Science Tsinghua University Beijing100084 China Laboratoire des Sciences du Climate et de l'Environnement LSCE Orme de Merisiers Gif-sur-Yvette91191 France Department of Earth System Science University of California Irvine 3232 Croul Hall IrvineCA92697-3100 United States CICERO Center for International Climate Research Oslo Norway Institute Pierre-Simon Laplace Sorbonne Université/CNRS Paris France Kayrros 33 Rue La Fayette ParisFR 75009 France Global Carbon Project CSIRO Oceans and Atmosphere Australia Capital Territory Australia College of Engineering Mathematics and Physical Sciences University of Exeter Exeter United Kingdom Department of Earth & Environment Sciences Columbia University United States Earth System Science Department Woods Institute for the Environment Precourt Institute for Energy Stanford University StanfordCA United States Energy and Resources Group Goldman School of Public Policy University of California BerkeleyCA United States School of Environmental Science The Tyndall Centre for Climate Change Research University of East Anglia Norwich United Kingdom Ispra Italy Center for Global Environmental Research National Institute for Environmental Studies Tsukuba Japan Key Laboratory of Land Surface Pattern and Simulation Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China Tsinghua Shenzhen International Graduate School Tsinghua University Shenzheng China Department of Electrical Engineering Tsinghua University Beijing100084 China Potsdam Institute for Climate Impact Research Potsdam14412 Germany

The diurnal cycle CO2 emissions from fossil fuel combustion and cement production reflect seasonality, weather conditions, working days, and more recently the impact of the COVID-19 pandemic. Here, for the first time we provide a daily CO2 emission dataset for the whole year of 2020 calculated from inventory and near-real-time activity data (called Carbon Monitor project: https://***) for power generation (for 29 countries), industry (for 73 countries), road transportation (for 406 cities), aviation and maritime transportation and residential fuel use sectors (which we estimate for 206 countries). It was previously suggested from preliminary estimates that did not cover the entire year of 2020 that the pandemics may have caused more than 8% annual decline of global CO2 emissions. Here we show from detailed estimates of the full year data that the global reduction was only 5.4% (-1,901 MtCO2, ±7.2% for 2-sigma range). This decrease is 5 times larger than the annual emission drop at the peak of the 2008 Global Financial Crisis. However, global CO2 emissions gradually recovered towards 2019 levels from late April with global partial re-opening. More importantly, global CO2 emissions even increased slightly by +0.9% in December 2020 compared with 2019, indicating the trends of rebound of global emissions. Later waves of COVID-19 infections in late 2020 and corresponding lockdowns have caused further CO2 emissions reductions particularly in western countries, but to a much smaller extent than the declines in the first wave. Despite partial mobility restrictions in European countries and in some US States that have been affected by the second and third waves of the pandemics, emission reductions observed in Autumn 2020 were much smaller than those of Spring 2020. That even substantial world-wide lockdowns of activity led to a one-time decline in global CO2 emissions of only 5.4% in one year highlights the significant challenges for climate change mitigation

关键词： Fossil fuels

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Spatio-temporal Differentiation of Residential Land for Coastal Town: A Case Study of Dalian Jinshitan

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Chinese Geographical Science 2016年第4期26卷 566-576页

作者： YANG Jun SUN Jing ZHAO Hongdan XI Jianchao LI Xueming Liaoning Key Laboratory of Physical Geography and Geomatics Liaoning Normal University Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences

Based on SPOT5 satellite remote sensing images and land use data in five time phases covering the period 1988–2012, the distribution characteristics, spatial differentiation processes, and driving mechanisms affecting the residential land of the Jinshitan Tourist Resort were studied. The work included a combination of GIS technology, adoption of the differentiation index D, and the multi-group differentiation-measure model D(m). The results provided a basis for the following conclusions: 1) From 1988 to 2012, the degree of differentiation of the rural residential land first decreased, and then increased. The general residential, commercial residential and garden-house land-types all showed declining trends, of which the garden-house type presented the most intense volatility. 2) The overall background of the traditional residential land type was gradually replaced by a new residential land type, and the total area of residential land increased year by year, significantly improving the overall residential conditions. The areas of the new residential land type showed growth, and were increasingly widely distributed in the coastal tourist resorts, transportation corridors, and scenic areas. 3) Government policy, social differentiation, market mechanisms, and individual choices(along with other factors) were mutually promoted, although still restrained. However, all of these factors interacted to constrain the developmental direction and the processes affecting tourism real estate in the Dalian Jinshitan Tourist Resort.

关键词： residential space differentiation differentiation degree residential conditions driving mechanism Dalian Jinshitan

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Emergy-based environmental accounting toward a sustainable Mongolia

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Journal of Geographical Sciences 2017年第10期27卷 1227-1248页

作者： LI Haitao BROWN Mark Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China Center for Environmental Policy Engineering School of Sustainable Infrastructure and Environment University of Florida Gainesville FI 32611 USA

An emergy-based environmental accounting of Mongolia is presented based on the data from 1995 to 2012. By calculating natural and economic inputs and a series of emergy indicators, this paper discusses Mongolia＇s resource use structure, economic situation, trade status and societal sustainability. The results show that the total emergy use for Mongolia changed from 2.83×10^22 sej in 1995 to 4.96×10^22 sej in 2012, representing a 75% increase over the 18 years of this study, yet its emergy per capita remains one of the lowest in the world （1.74× 10^16 sej/capita）. The emergy money ratio （EMR） of Mongolia during 1995-2012 decreased from 1.99×10^13 sej/USD to 7.75×10^12 sej/USD, which indicates that the power of a dollar for purchasing real wealth in Mongolia was declining, while the relatively high absolute values compared to its trading partners and even the world average EMR suggests that Mongolia is continuing a trade disadvantage. Mongolia＇s emergy exchange ratio is increasingly less than one to the point that in 2012 the ratio was 0.3 suggesting that the exported emergy was over 3.3 times greater than the imported emergy. The growing dependence on imports and the dramatic increase in exports suggests that Mongolia＇s economy is increas- ingly vulnerable to downturns in the world economy.

关键词： emergy resources sustainability Mongolia

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Reconstruction of cropland spatial patterns and its spatiotemporal changes over the 20th century on the Songnen Plain, Northeast China

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Journal of Geographical Sciences 2017年第10期27卷 1209-1226页

作者： ZHANG Lijuan JIANG Lanqi ZHANG Xuezhen Key Laboratory of Remote Sensing Monitoring of Geographic Environment Harbin Normal University Harbin 150025 China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China Jiangsu Collaborative Innovation Center for Climate Change Nanjing 210093 China

We initially estimated the cropland area at county level using local historical documents for the Songnen Plain （SNP） in the 1910s and 1930s. We then allocated this cropland area to grid cells with a size of 1 km ×1 km, using a range of cultivation possibilities from high to low; this was based on topography and minimum distances to rivers, settlements, and traffic lines. Cropland areas for the 1950s were obtained from the Land Use Map of Northeast China, and map vectorization was performed with ArcGIS technology. Cropland areas for the 1970s, 1980s, 1990s, 2000s, and 2010s were retrieved from Landsat images. We found that the cropland areas were 4.92 ×10^4 km^2 and 7.60 ×10^4 km^2, accounting for 22.8% and 35.2% of the total area of the SNP in the 1910s and 1930s, respectively, which increased to 13.14 × 10^4 km^2, accounting for 60.9% in the 2010s. The cropland increased at a rate of 1.18 ×10^4 km^2 per decade from the 1910s to 1970s while it was merely 0.285 ×10^4 km^2 per decade from the 1970s to 2010s. From the 1910s to 1930s, new cultivation mainly occurred in the central SNP while, from the 1930s to 1970s, it was mainly over the western and northern parts. This spatially explicit reconstruction could be offered as primary data for studying the effects of changes in human-induced land cover based on climate change over the last century.

关键词： land use/cover changes agricultural development historical documents gridding data

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Spatio-temporal variation of the wet-dry conditions from 1961 to 2015 in China

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Science China Earth Sciences 2017年第11期60卷 2041-2050页

作者： YUAN QuanZhi WU ShaoHong DAI ErFu ZHAO DongSheng ZHANG XueRu REN Ping Key Lab of Land Resources Evaluation and Monitoring in Southwest Ministry of EducationSichuan Normal UniversityChengdu 610068China Institute of Geography and Resources Science Sichuan Normal UniversityChengdu 610101China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China College of Architecture and Urban Planning Chongqing Jiaotong UniversityChongqing 400074China School of Public Administration Hebei University of Economics and BusinessShijiazhuang 050061China

As an important part of the regional environment, the wet-dry climate condition is determined by precipitation and potential evapotranspiration （expressed as ETo）. Based on weather station data, this study first calculated ETo by using the FAO56 Penrnan-Monteith model. Then, the dryness index K （ratio of ETo to precipitation） was used to study the spatio-temporal variation of the wet-dry condition in China from 1961 to 2015; moreover, dominant climatic factors of the wet-dry condition change were discussed. The annual precipitation and ETo of the Qinling-Huaihe line were close to a balance （K≈1.0）. The annual precipitation in most areas exceeded the ETo in the south of this line and the east of Hengduan Mountains （K〈0.0）, where the climate is wet. Furthermore, the precipitation in the northwest inland areas of China, where the climate is dry, was markedly lower than ETo （K≥4.0）. The overall annual K of China fluctuated around the 55-year mean and its linear trend was not significant. However, a relatively wet period of about 10 yr （1987-1996） was recorded. The overall annual K of China showed strong cyclicality on the time scale of 3, 7-8, 11 and 26-28 yr, and regional differences of the annual K trends and cyclicality were large. The degrees of wetness in the Northwest China and western Qinghai-Tibet Plateau were substantially increased, whereas the degrees of dryness in the Yunnan-Guizhou Plateau, Sichuan Basin, and Loess Plateau were markedly increased. The linear trend of the annual K in most regions of China was not significant, and the annual K of most areas in China showed strong cyclicality on the 8-14 yr time scale. Precipitation was the dominant factor of wet-dry condition change in most areas, especially in North China, where the annual K change was highly correlated with precipitation.

关键词： Wet-dry condition Climate dryness index Potential evapotranspiration Climate change China

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Reconstruction of Lu-level cropland areas in the Northern Song Dynasty （AD976-1078）

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Journal of Geographical Sciences 2017年第5期27卷 606-618页

作者：何凡能李美娇李士成 Key Laboratory of Land Surface Pattern and Simulation institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China University of Chinese Academy of Sciences Beijing 100049 China School of Public Administration China University of Geosciences Wuhan 430074 China

Based on data on taxed-cropland area and on the number of households in historical documents, a probabilistic model of cropland distribution and a cropland area allocation model were designed and validated. Cropland areas for the years AD976, 997, 1066, and 1078 were estimated at the level of Lu（an administrative region of the Northern Song Dynasty）. The results indicated that（1） the cropland area of the whole study region for AD976, 997, 1066, and 1078 was about 468.27 million mu（a Chinese unit of area, with1 mu=666.7m2）, 495.53 million mu, 697.65 million mu, and 731.94 million mu, respectively. The fractional cropland area（FCA） increased from 10.7% to 16.8%, and the per capita cropland area decreased from 15.7 mu to 8.4 mu.（2） With regard to the cropland spatial pattern, the FCA of the southeast, north, and southwest regions of the Northern Song territory increased by 12.0%, 5.2%, and 1.2%, respectively. The FCA of some regions in the Yangtze River Plain increased to greater than 40%, and the FCA of the North China Plain increased to greater than 20%. However, the FCA of the southwest region（except for the Chengdu Plain） in the Northern Song territory was less than 6%.（3） There were 84.2% Lus whose absolute relative error was smaller than 20% in the mid Northern Song Dynasty. The validation results indicate that our models are reasonable and that the results of reconstruction are credible.

关键词： land use/cover change cropland area Lu-level reconstruction spatial–temporal characteristics Northern Song Dynasty

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Examining the influence of the implementation of Major Function-oriented Zones on built-up area expansion in China

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Journal of Geographical Sciences 2017年第6期27卷 643-660页

作者： LIU Wenchao LIU Jiyuan KUANG Wenhui NING Jia Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natura Resources Research CAS Beijing 100101 China College of Urban and Environment Science Tianjin Normal University Tianjin 300387 China University of Chinese Academy of Sciences Beijing 100049 China

China had implemented the national strategies for Major Function-oriented Zones （MFOZs） to realize the goal of national sustainable development since 2010. This study analyzed and compared spatio-temporal characteristics and differences in built-up area for China＇s MFOZs using a China＇ s Land Use Database （CLUD） derived from high-resolution remotely sensed images in the periods of 2000-2010 and 2010-2013. To sum up：（1） The percentage of built-up area in each of the MFOZs was significantly different, revealing the gradient feature of national land development based on the distribution of the main functions. （2） Annual growth in built-up area in optimal development zones （ODZs） decreased signifi- cantly during 2010-2013 compared with the period 2000-2010, while annual growth in built-up area in key development zones （KDZs）, agricultural production zones （APZs） and key ecological function zones （KEFZs） increased significantly. （3） In ODZs, the average annual increase in built-up area in the Yangtze River Delta region was significantly higher than in other regions; the average area increase and rate of increase of built-up area in KDZs was faster in the western region than in other regions; average annual area growth of built-up area in APZs in the northeast, central and western regions was twice as high as the previous decade on average; the annual rate of change and increase in the dynamic degree of built-up area were most notable in KEFZs in the central region. （4） The spatial pattern and charac- teristics of built-up area expansions in the period 2010-2013 reflected the gradient feature of the plan for MFOZs. But the rate of increase locally in built-up area in ODZs, APZs and KEFZs is fast, so the effective measures must be adopted in the implementation of national and regional policies. The conclusions indicated these methods and results were meaningful for future regulation strategies in optimizing national land development in China.

关键词： Major Function-oriented Zones satellite remote sensing land use change development of urban andtown built-up area China

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Influences of agricultural phenology dynamic on land surface biophysical process and climate feedback

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Journal of Geographical Sciences 2017年第9期27卷 1085-1099页

作者： LIU Fengshan CHEN Ying SHI Wenjiao ZHANG Shuai TAO Fulu GE Quansheng Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Re- sources Research CAS Beijing 100101 China Fujian Agriculture and Forestry University Fuzhou 350002 China College of Resources and Environment University of Chinese Academy of Sciences Beijing 100049 China

Response and feedback of land surface research priorities in the field of geoscience. The process to climate change is one of the current study paid more attention to the impacts of global change on land surface process, but the feedback of land surface process to climate change has been poorly understood. It is becoming more and more meaningful under the framework of Earth system science to understand systematically the relationships between agricultural phenology dynamic and biophysical process, as well as the feedback on climate. In this paper, we summarized the research progress in this field, including the fact of agricultural phenology change, parameterization of phenology dynamic in land surface progress model, the influence of agricultural phenology dynamic on biophysical process, as well as its feedback on climate. The results showed that the agriculture phenophase, represented by the key phenological phases such as sowing, flowering and maturity, had shifted significantly due to the impacts of climate change and agronomic management. The digital expressions of land surface dynamic process, as well as the biophysical process and atmospheric process, were improved by coupling phenology dynamic in land surface model. The agricultural phenology dynamic had influenced net radiation, latent heat, sensible heat, albedo, temperature, precipitation, circulation, playing an important role in the surface energy partitioning and climate feedback. Considering the importance of agricultural phenology dynamic in land surface biophysical process and climate feedback, the following research priorities should be stressed：（1） the interactions between climate change and land surface phenology dynamic; （2） the relations between agricultural phenology dynamic and land surface reflectivity at different spectrums; （3） the contributions of crop physiology characteristic changes to land surface biophysical process; （4） the regional differences of climate feedbacks from phenology d

关键词： agricultural phenology land surface biophysical process land surface process model climate feedback

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Reponses and sensitivities of maize phenology to climate change from 1981 to 2009 in Henan Province, China

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Journal of Geographical Sciences 2017年第9期27卷 1072-1084页

作者： LIU Yujie QIN Ya GE Quansheng DAI Junhu CHEN Qiaomin Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China Xi'an University of Science and Technology College of Surveying and Mapping Science and Technology Xi'an 710054 China University of Chinese Academy of Sciences Beijing 100049 China

With the global warming, crop phenological shifts in responses to climate change have become a hot research topic. Based on the long-term observed agro-meteorological phenological data （1981-2009） and meteorological data, we quantitatively analyzed temporal and spatial shifts in maize phenology and their sensitivities to key climate factors change using climate tendency rate and sensitivity analysis methods. Results indicated that the sowing date was significantly delayed and the delay tendency rate was 9.0 d·10a^-1. But the stages from emergence to maturity occurred earlier （0.1 d·10a^-1〈θ〈1.7 d·10a^-1, θ is the change slope of maize phenology）. The length of vegetative period （VPL）（from emergence to tasseling） was shortened by 0.9 d·10a^-1, while the length of generative period （GPL）（from tasseling to maturity） was lengthened by 1.7 d·10a^-1. The growing season length （GSL）（from emergence to maturity） was lengthened by 0.4 d·10a^-1. Correlation analysis indicated that maize phenology was significantly correlated with average temperature, precipitation, sunshine duration and growing degree days （GDD）（p〈0.01）. Average temperature had significant negative correlation relationship, while precipitation, sunshine duration and growing degree days had significant positive correlations with maize phenology. Sensitivity analysis indicated that maize phenology showed different responses to variations in key climate factors, especially at different sites. The conclusions of this research could provide scientific supports for agricultural adaptation to climate change to address the global food security issue.

关键词： climate change maize phenology trend analysis sensitivity

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