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Chen, X.; Liu, X.; Liu, L.; Zhang, Y.; Guo, J.; Huang, J.; Zhou, M.; Zhao, Y.; Wu, L.; Yang, L.; Lun, F.
© 2018 by the author
. How to meet food demands with limited cropland has become a serious problem worldwide, especially in China. Global and national food trade can alleviate regional food unbalance among different countries or regions to some extent. The embedded virtual land also flows with food trade, and reasonable food trade can save global croplands and protect local ecosystems. Therefore, it is of great importance to study how trade influences land use as well as its associated environmental consequences. Recent studies have mainly focused on global food trade and its associated virtual land flow; however, only a few have focused on national food trade and its associated virtual land flow. Thus, this study aims to explore the domestic wheat trade and its associated virtual land flows in China during the period 2010-2015, based on the CHINAGRO model and previous studies. The Huang-Huai-Hai Plain and its surrounding regions were the main producers and consumers of wheat and virtual wheat. Without wheat stocks and international wheat trade, the annual domestic wheat trade accounted for 16.43% of the total national wheat production in China. Anhui was the largest net exporter of wheat, followed by Henan, while the developed areas such as Beijing, Guangdong, and Shanghai were the main net importers. Additionally, as an important transfer region, Jiangsu was the largest exporter and importer of wheat virtual cropland, but it finally presented as a net exporter of wheat cropland. During this period, domestic wheat trade led to a total land savings of 2.62 Mha/a, accounting for 10.80% of Chinese wheat cropland. However, compared with the year 2010, Shandong, Hebei, and Sichuan turned into wheat net importers in 2015, which was due to different reasons such as national agriculture polices and economic development. In addition, the net virtual cropland per capita has been greatly influenced by local economic development
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Ensuring food security has always been a top priority of the Chinese government
. However, China’s grain supply is facing challenges due to limited resources for grain production and the growth of domestic grain consumption. Reducing post-harvest grain loss represents one of the most realistic and effective ways to ensure grain security in China. In view of the importance of grain sales in the post-harvest period, we conducted a survey, interviewing 1890 grain sellers across 54 regions in 9 provinces of China, to investigate the factors affecting post-harvest grain loss during sales. The results of the survey show that grain storage conditions have the greatest impact on post-harvest grain loss, followed by transportation. Display and sales have the least impact on grain loss. The Tobit regression model was used to analyze the main factors affecting post-harvest grain loss during sales. The findings suggest that the seller’s education level, years of working as a seller, the conditions of grain storage, and the supply and management level of public facilities in the market were negatively correlated with grain loss in the sales process, whereas the seller’s age, the separation of sales shops and storage warehouses, and the fall season were positively correlated with grain loss. Policy implications are also provided for potential future policy decisions
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Changes in glacial lakes and the consequences of these changes, particularly on the development of water resources and management of glacial lake outburst flood (GLOF) risk, has become one of the challenges in the sustainable development of high mountain areas in the context of global warming
. This paper presents the findings of a study on the distribution of, and area changes in, glacial lakes in the Koshi basin in the central Himalayas. Data on the number of glacial lakes and their area was generated for the years 1977, 1990, 2000, and 2010 using Landsat satellite images. According to the glacial lake inventory in 2010, there were a total of 2168 glacial lakes with a total area of 127.61 km2 and average size of 0.06 km2 in the Koshi basin. Of these, 47% were moraine dammed lakes, 34.8% bedrock dammed lakes and 17.7% ice dammed lakes. The number of glacial lakes increased consistently over the study period from 1160 in 1977 to 2168 in 2010, an overall growth rate of 86.9%. The area of glacial lakes also increased from 94.44 km2 in 1977 to 127.61 km2 in 2010, a growth rate of 35.1%. A large number of glacial lakes in the inventory are small in size (≤ 0.1 km2). End moraine dammed lakes with area greater than 0.1 km2 were selected to analyze the change characteristics of glacial lakes in the basin. The results show that, in 2010, there were 129 lakes greater than 0.1 km2 in area; these lakes had a total area of 42.92 km2 in 1997, increasing to 63.28 km2 in 2010. The distribution of lakes on the north side of the Himalayas (in China) was three times higher than on the south side of the Himalayas (in Nepal). Comparing the mean growth rate in area for the 33 year study period (1977-2010), the growth rate on the north side was found to be a little slower than that on the south side. A total of 42 glacial lakes with an area greater than 0.2 km2 are rapidly growing between 1977 and 2010 in the Koshi basin, which need to be paid more attention to monitoring in the future and to identify how critical they are in terms of GLOF
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Kargel, J. S.; Leonard, G. J.; Shugar, D. H.; Haritashya, U. K.; Bevington, A.; Fielding, E. J.; Fujita, K.; Geertsema, M.; Miles, E. S.; Steiner, J.; Anderson, E.; Bajracharya, S.; Bawden, G. W.; Breashears, D. F.; Byers, A.; Collins, B.; Dhital, M. R.; Donnellan, A.; Evans, T. L.; Geai, M. L.; Glasscoe, M. T.; Green, D.; Gurung, D. R.; Heijenk, R.; Hilborn, A.; Hudnut, K.; Huyck, C.; Immerzeel, W. W.; Jiang, L.; Jibson, R.; Kaab, A.; Khanal, N. R.; Kirschbaum, D.; Kraaijenbrink, P. D. A.; Lamsal, D.; Liu, S.; Lv, M.; Mckinney, D.; Nahirnick, N. K.; Nan, Z.; Ojha, S.; Olsenholler, J.; Painter, T. H.; Pleasants, M.; Kc, P.; Yuan, Q.; Raup, B. H.; Regmi, D.; Rounce, D. R.; Sakai, A.; Shangguan, D.; Shea, J. M.; Shrestha, A. B.; Shukla, A.; Stumm, D.; Van Der Kooij, M.; Voss, K.; Wang, X.; Weihs, B.; Wolfe, D.; Wu, L.; Yao, X.; Yoder, M. R.; Young, N.
The Gorkha earthquake (M 7
.8) on 25 April 2015 and later aftershocks struck South Asia, killing ~9,000 and damaging a large region. Supported by a large campaign of responsive satellite data acquisitions over the earthquake disaster zone, our team undertook a satellite image survey of the earthquakes’ induced geohazards in Nepal and China and an assessment of the geomorphic, tectonic, and lithologic controls on quake-induced landslides. Timely analysis and communication aided response and recovery and informed decision makers. We mapped 4,312 co-seismic and post-seismic landslides. We also surveyed 491 glacier lakes for earthquake damage, but found only 9 landslide-impacted lakes and no visible satellite evidence of outbursts. Landslide densities correlate with slope, peak ground acceleration, surface downdrop, and specific metamorphic lithologies and large plutonic intrusions
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Wu, G.; Li, Z.; Fu, C.; Zhang, X.; Zhang, R.; Zhang, R.; Zhou, T.; Li, J.; Li, J.; Zhou, D.; Wu, L.; Zhou, L.; He, B.; Huang, R.
Scientific issues relevant to interactions between aerosols and the Asian monsoon climate were discussed and evaluated at the 33rd 'Forum of Science and Technology Frontiers' sponsored by the Department of Earth Sciences at the Chinese Academy of Sciences
. Major results are summarized in this paper. The East Asian monsoon directly affects aerosol transport and provides a favorable background circulation for the occurrence and development of persistent fog-haze weather. Spatial features of aerosol transport and distribution are also influenced by the East Asian monsoon on seasonal, inter-annual, and decadal scales. High moisture levels in monsoon regions also affect aerosol optical and radiative properties. Observation analyses indicate that cloud physical properties and precipitation are significantly affected by aerosols in China with aerosols likely suppressing local light and moderate rainfall, and intensifying heavy rainfall in southeast coastal regions. However, the detailed mechanisms behind this pattern still need further exploration. The decadal variation in the East Asian monsoon strongly affects aerosol concentrations and their spatial patterns. The weakening monsoon circulation in recent decades has likely helped to increase regional aerosol concentrations. The substantial increase in Chinese air pollutants has likely decreased the temperature difference between land and sea, which favors intensification of the weakening monsoon circulation. Constructive suggestions regarding future studies on aerosols and monsoons were proposed in this forum and key uncertain issues were also discussed
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Li, X.; Cheng, G.; Jin, H.; Kang, E.; Che, T.; Jin, R.; Wu, L.; Nan, Z.; Wang, J.; Shen, Y.
This paper provides an overview of the current status of the cryosphere in China and its changes
. Up-to-date statistics of the cryosphere in China are summarized based on the latest available data. There are 46,377 glaciers in China, covering an area of 59,425 km2. The glacier ice reserve is estimated to be about 5600 km3 and the annual glacier runoff is about 61.6 × 109 m3. The continuous snow cover extent (> 60 days) in China is about 3.4 × 106 km2 and the maximum water equivalent is 95.9 × 109 m3 yr− 1. The permafrost area in China is about 1.72 × 106 km2. The total ground ice reserve on the Qinghai–Tibetan Plateau is estimated to be about 10,923 km3. Recent investigations indicated that glacier areas in China have shrunk about 2–10% over the past 45 yr. Total glacier area has receded by about 5.5%. Snow mass has increased slightly. Permafrost is clearly degrading, as indicated by shrinking areas of permafrost, increasing depth of the active layer, rising of lower limit of permafrost, and thinning of the seasonal frost depth. Some models predict that glacier area shrinkage could be as high as 26.7% in 2050, with glacier runoff increasing until its maximum in about 2030. Although snow mass shows an increasing trend in western China, in eastern China the trend is toward decreasing snow mass, with increasing interannual fluctuations. Permafrost degradation is likely to continue, with one-third to one-half of the permafrost on the Qinghai–Tibetan Plateau anticipated to degrade by 2100. Most of the high-temperature permafrost will disappear by then. The permafrost in northeastern China will retreat further northward
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Affected by Global Warming in the Mountains of the Himalayan RegionOne of the major objectives of the study was to identify areas where GLOF events had occurred and lakes that could pose a potential threat of GLOF in the near future
. Out of a surprisingly large total of 354 glacial lakes, the researchers found 19 lakes that are potentially dangerous in the Poiqu basin and (Tama Koshi) in China. . These results thus provide the basis for the development of a monitoring and early warning system and for the planning and prioritisation of disaster mitigation efforts that could save many lives and properties situated downstream as well as guide infrastructure planning. In addition, it is anticipated that this study will provide useful information for many of those concerned with water resources and land-use planning
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