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Isotopic composition of atmospheric water vapor before and after the monsoon＇s end in the Nagqu River Basin

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Chinese Science Bulletin 2005年第23期50卷 2755-2760页

作者： yu wusheng YAO Tandong TIAN Lide WANG yu YIN Changliang Key Laboratory of Cryosphere and Environment Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China Key Laboratory of Cryosphere and Environment Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China

Atmospheric water vapor samples were col-lected in the Nagqu River Basin in the middle of Tibetan Plateau between August and October in 2004. Results show that there exist some fluctuations of the δ 18O of atmospheric water vapor, especially before and after the monsoon’s end. Moreover, the variety trend of the δ 18O of atmospheric water vapor inverse correlates with that of dew point. Precipitation events make an important effect upon the variation of δ 18O of atmospheric water vapor. During the whole sampling pe-riod, the δ 18O values of atmospheric water vapor are low while precipitation events occurred. The moisture origins also contribute to the variation of δ 18O of atmospheric water vapor. The oceanic moisture transported by the southwest monsoon results in lower δ18O of atmospheric water vapor in the Nagqu River Basin. Compared with the influence of the oceanic moisture, the δ 18O values, however, appear high re-sulting from the effect of the continental air mass in this re-gion.

关键词：那曲河流域西藏氧同位素大气水蒸气季风

What Determines China's Grain Imports and Self-sufficiency? The Role of Rising Domestic Costs and Varying World Market Prices

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China & World Economy 2019年第5期27卷 1-24页

作者： wusheng yu Tianxiang Li Jing Zhu Department of Food and Resource Economics University of CopenhagenDenmark College of Economics & Management Nanjing Agricultural UniversityChina China Center for Food Security Studies Nanjing Agricultural UniversityChina

China s grain sectors have faced unprecedented challenges in recent years as the ever-increasing and historically high level of grain output has failed to reduce grain imports. On the contrary, high grain imports and high domestic stock have accompanied historically high domestic output, a situation dubbed the "triple high" phenomenon in current policy discussion. This paper explores the role of widening domestic-world market price gaps in determining the triple high *** earlier studies that relied on production capacities, this paper argues that domestic production and demand (hence imports) are functions of domestic and world market prices and proposes an analytical framework to explicitly capture such price gaps under restricted trade linkages in general equilibrium. Following this approach, a set of price scenarios for the 2011-2020 period are constructed and simulated in a computable general equilibrium model. Results from the core scenarios, in which recent domestic and world market price trends are assumed to continue, suggest that further widening price gaps would substantially increase grain imports and reduce domestic output (by 60 million tons) and self-sufficiency ratios from base levels. In the alternative scenarios with larger (smaller) price gaps, we find higher (lower) imports and larger (smaller) decreases in domestic output and self-sufficiency ratios. Such results provide important policy implications as China's agricultural policy undergoes significant adjustment.

关键词： computable general equilibrium model domestic-world market price gaps food security grain imports self-sufficiency ratio triple high

Seasonal variations of stable isotope in precipitation and moisture transport at yushu,eastern Tibetan Plateau

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Science China Earth Sciences 2008年第8期51卷 1121-1128页

作者： TIAN LiDe MA LingLong yu wusheng LIU ZhongFang YIN ChangLiang ZHAO ZhongPing TANG Wei WANG yu Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100085China State Key Laboratory of Cryosphere Sciences Chinese Academy of SciencesLanzhou 730000China

Precipitation δ 18O at yushu, eastern Tibetan Plateau, shows strong fluctuation and lack of clear seasonality. The seasonal pattern of precipitation stable isotope at yushu is apparently different from either that of the southwest monsoon region to the south or that of the inland region to the north. This different seasonal pattern probably reflects the shift of different moisture sources. In this paper, we present the spatial comparison of the seasonal patterns of precipitation δ 18O, and calculate the moisture transport flux by using the NCAR/NCEP reanalysis data. This allows us to discuss the relation between moisture transport flux and precipitation δ 18O. This study shows that both the southwest monsoon from south and inland air mass transport from north affected the seasonal precipitation δ 18O at yushu, eastern Tibetan Plateau. Southwest monsoon brings the main part of the moisture, but southwest transport flux is weaker than in the southern part of the Tibetan Plateau. However, contribution of the inland moisture from north or local evaporation moisture is enhanced. The combined effect is the strong fluctuation of summer precipitation δ 18O at yushu and comparatively poor seasonality.

关键词： Tibetan Plateau yushu precipitation stable isotope moisture transport

Glacial distribution and mass balance in the Yarlung Zangbo River and its influence on lakes

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Chinese Science Bulletin 2010年第20期55卷 2072-2078页

作者： YAO TanDong LI ZhiGuo YANG Wei GUO XueJun ZHU LiPing KANG ShiChang WU YanHong yu wusheng Key Laboratory of Tibetan Environment Changes & Land Surface Processes Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China State Key Laboratory of Cryosphere Chinese Academy of Sciences Lanzhou 730000 China Key Laboratory of Digital Earth Sciences Center for Earth Observation and Digital Earth Chinese Academy of Sciences Beijing 100190 China

Glaciers in the Yarlung Zangbo River witness severe glacial retreat nowadays,which gives important influence on lake processes in the *** have studied glacial distribution,glacial mass balance and found large deficit in glacial mass and its impact in the *** study also integrated the variation in glacial-fed lakes of the Nam Co and Ranwu Lake,and presented an initial assessment of the impact of glacial mass balance on *** study has shown a significant contribution of glacial melting to recent lake expansion and lake level rising.

关键词：冰川物质平衡冰川分布雅鲁藏布江湖泊变化冰川退缩冰川融化纳木错上升

Stable isotopic compositions of precipitation events from Kathmandu, southern slope of the Himalayas

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Chinese Science Bulletin 2014年第34期59卷 4838-4846页

作者： Tek Bahadur Chhetri Tandong Yao wusheng yu Li Ding Daniel Joswiak Lide Tian Lochan Prasad Devkota Dongmei Qu Key Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau ResearchChinese Academy of Sciences University of Chinese Academy of Sciences Central Department of Hydrology and Meteorology Tribhuvan University Kathmandu Nepal Yinchuan Meteorological Administration

Investigation of temporal variations in the stable d18 O and d D isotopes from Kathmandu's precipitation events shows that the relatively enriched d18 O and d D values in the winter(the dry season, dominated by the westerlies) were positively correlated with temperature,indicating a temperature effect controlling the changes of d18 O and d D. However, the d18 O and d D values were depleted in the summer(the wet season, dominated by the Indian monsoon), which were negatively correlated with precipitation amount, indicating an amount effect. In addition, the comparison of stable isotopes in precipitation from Kathmandu and Mawlong(near the Bay of Bengal)shows that the overall trends of d18 O and d D values at Kathmandu generally approximate those at ***, there remain many differences between the details of the isotopic changes at Kathmandu versus those at Mawlong. Compared with those at Mawlong, the further rainout effect and the more intense lift effect of the oceanic moisture by the high mountains resulted in the moredepleted d18 O and d D values in summer precipitation at Kathmandu. A deuterium excess and the local meteoric water lines reveal that evaporation at Kathmandu exceeds that at Mawlong. The data also show that the Indian monsoon activities at Mawlong are more intense than those at Kathmandu.

关键词：同位素组成稳定同位素降水事件喜马拉雅山南坡温度效应印度季风夏季降水

Temporal and spatial variations of δ^18O in precipitation of the Yarlung Zangbo River Basin

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Journal of Geographical Sciences 2007年第3期17卷 317-326页

作者： LIU Zhongfang TIAN Lide YAO Tandong GONG Tongliang YIN Changliang yu wusheng Institute of Tibetan Plateau Research CAS Beijing 100085 China Key Laboratory of Cryosphere and Environment Cold and Arid Regions Environmental and Engineering Research Institute CAS Lanzhou 730000 China Institute of Tibetan Water Resource Reconnaissance and Designing Lhasa 850000 China

This paper reveals the temporal and spatial variations of stable isotope in precipitation of the Yarlung Zangbo River Basin based on the variations of δ^18O in precipitation at four stations （Lhaze, Nugesha, Yangcun and Nuxia） in 2005. The results show that δ^18O of precipitation has distinct seasonal changes in the Yarlung Zangbo River Basin. The higher value of δ^18O occurs in spring prior to monsoon precipitation, and the lower value occurs during monsoon precipitation. From the spatial variations, with the altitude-effect and rainout process during moisture transport along the Yarlung Zangbo River Valley, δ^18O of precipitation is gradually depleted. Thus, δ^18O of precipitation decreases gradually from the downstream to the upstream, and the lapse rate of δ^18O in precipitation is approximately 0.34‰/100m and 0.7%J‰/100km for the two reasons. During monsoon precipitation, spatial variation of δ^18O in precipitation is dominated by the amount effect in the large scale synoptic condition.

关键词： Yarlung Zangbo River Basin δ^18O precipitation temporal and spatial variations

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植物叶片水稳定同位素研究进展

生态学报 2013年第4期33卷 1031-1041页

作者：罗伦余武生万诗敏周平中国科学院青藏高原环境变化与地表过程重点实验室中国科学院青藏高原研究所北京100101 中国科学院研究生院北京100049 天津城市建设学院基础学科部天津300384 长春气象探测中心长春130062

植物叶片水稳定同位素变化可以直接沟通植物叶片内部与外界的物质和能量联系,并能够反映植物生长周围的气候与生态信息。另外,植物叶片水作为参与水循环的一个重要环节,了解叶片水稳定同位素组成有助于揭示其在局地水体稳定同位素循环... 详细信息

植物叶片水稳定同位素变化可以直接沟通植物叶片内部与外界的物质和能量联系,并能够反映植物生长周围的气候与生态信息。另外,植物叶片水作为参与水循环的一个重要环节,了解叶片水稳定同位素组成有助于揭示其在局地水体稳定同位素循环中的分配与贡献。概述了国内外叶片水稳定同位素研究现况;介绍了叶片水稳定氢、氧同位素在植物体中的分馏过程及形式(热力学平衡分馏、动力学分馏以及生化分馏)以及影响叶片水稳定同位素组成的气象和生态因子;阐述了叶片水稳定同位素修正的Craig-Gordon稳态模型、string-of-lakes模型、Péclet效应的稳态模型、非稳态效应的模型、Péclet效应的非稳态模型以及二维模型的构建与完善过程;最后讨论了植物叶片水稳定同位素研究存在的问题,并从叶片水稳定同位素与气象、生态因子的关系,叶片水蒸腾线的斜率和截距及过量氘的意义,模型适用性的验证以及叶片水稳定同位素在水文循环的应用等方面展望了研究方向。

关键词：植物叶片水稳定同位素模型

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语境与日语话语的语用原则

江西科技师范学院学报 2008年第5期3卷 74-77,115页

作者：于无声张凤江西科技师范学院江西南昌330013 江西青年职业学院江西南昌330013

本文从语用原则角度出发,结合语境,阐述日语话语的生成机制,并认为在进行日语会话时,必须遵守的主要语用原则为四项,分别是内省主义原则、他者本位主义原则、礼仪原则和空间原则。

关键词：日语口语语境交际语用原则

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高亚洲地区冰崩灾害的研究进展

冰川冻土 2018年第6期40卷 1141-1152页

作者：胡文涛姚檀栋余武生杨威高杨中国科学院青藏高原研究所北京100101 中国科学院大学北京100049

在全球气候变化的背景下,冰崩灾害极有可能成为人类面临的新常态。特别是在高亚洲地区,冰崩灾害事件严重威胁"亚洲水塔"的命运和"第三极"的生态安全。因此,研究冰崩灾害事件对于保障"一带一路"国家战略的顺利实施和保护"一带一路"沿线... 详细信息

在全球气候变化的背景下,冰崩灾害极有可能成为人类面临的新常态。特别是在高亚洲地区,冰崩灾害事件严重威胁"亚洲水塔"的命运和"第三极"的生态安全。因此,研究冰崩灾害事件对于保障"一带一路"国家战略的顺利实施和保护"一带一路"沿线国家的生产与生存环境具有重要的现实意义。通过梳理历史上有记录的几次冰崩灾害事件,系统介绍冰崩的发生过程;再从冰崩体的物质组成、冰崩体的运动特征、冰崩发生的可能原因以及冰崩的影响等方面总结了冰崩的研究内容;重点阐述了冰崩的研究方法;最后讨论了当前冰崩研究存在的问题,并从冰崩研究方法等角度展望了未来冰崩灾害事件的研究方向。

关键词：冰崩冰川动力学遥感影像模型灾害评估