Contribution of external forcing to summer precipitation trends over the Qinghai-Tibet Plateau and Southwest China

在过去的60年中,全球气候经历了快速变暖和短暂的变暖停滞,而中国的区域降水也经历了多样而复杂的变化.本文分析了1961年至2014年外强迫因子对青藏高原和中国西南地区夏季降水趋势的影响.观测数据显示,青藏高原的夏季降水呈增加趋势,而中国西南地区的夏季降水呈减少趋势,这两个相邻地区的夏季降水变化趋势相反.利用CMIP6数据,本文研究了不同外强迫因子对两个区域夏季降水趋势的影响.结果表明,温室气体对青藏高原夏季降水的增加具有显著影响,而气溶胶在中国西南地区夏季降水减少中起主要作用。

Co-benefits of Local Air Pollutants and Greenhouse Gas Reduction Achieved by Hydropower Development in Xizang(Tibet) Autonomous Region, China

Hydropower development in Xizang(Tibet) Autonomous Region plays a vital role in co-control of local air pollutants and greenhouse gas(GHG) in China. According to emission factors of local air pollutants and GHG of coal-fired power industry in different hydropower service regions, we estimate the effect and synergy of local air pollutants and GHG reduction achieved by hydropower development in Tibet, examine the main factors constraining the effect and synergy, using correlation analysis and multiple regression analysis. The results show that: 1) During the period from 2006 to 2012, the effect of local air pollutants and GHG reduction achieved by hydropower development in Tibet decreased as a whole, while the synergy increased first and decreased afterwards. 2) The effect and synergy of local air pollutants and GHG reduction achieved by hydropower development in Tibet vary significantly across different hydropower service regions. The effect based on emission levels of Central China power grid(CCPG) and Northwest China power grid(NCPG) was more significant than that based on emission level of national power grid(NPG) from 2006 to 2012, and the synergy based on emission levels of CCPG and NCPG was also more significant than that based on emission level of NPG from 2010 to 2012. 3) The main factors constraining the effect and synergy based on emission levels of NCPG and CCPG included SO2 removal rate and NOx removal rate, the effect and synergy based on emission level of NPG was mainly influenced by net coal consumption rate. 4) Transferring hydropower from Tibet to NCPG and CCPG, and substituting local coal-fired power with hydropower can greatly help to co-control local air pollutants and GHG, transform the emission reduction pattern of the power industry and optimize energy structure.

An X-Ray Diffraction Study of an Inclusion in Diamond from the Luobusha Chromite Deposit in Tibet,China

Diamond was found in podiform chromitites of ophiolite and harzburgite from Luobusha, Tibet. There are silicate inclusions in some diamond grains from this area. In the present work, the CCD (charge coupled detector) technology of X-ray powder diffraction was applied to the study of the inclusion in diamond from the ophiolite of Tibet. Diffraction patterns are obtained even though the inclusion is only 20 μm in crystal size. The results show that the inclusion in diamond consists of talc and clinochrysotile. Therefore, it is clear that the diamond from the ophiolite of Luobusha, Tibet, is natural diamond rather than a synthetic one.

Planation Surfaces on the Tibet Plateau,China

A planation hypothesis is proposed to explain landform evolution of the Tibet Plateau.A denudation threshold(T),the maximum potential denudation rate for a certain type of rock,is introduced to explain the combined effects of lithology and tectonics on landform evolution.If the tectonic uplifting rate(U)is equal to or less than the threshold rate(U≤T),the tectonic uplifting and terrain denudation are in dynamic equilibrium,and landforms are in a steady state.The end product should be planation surfaces whether the original landforms are flat plains or deeply dissected mountains.If U>T,uplift and denudation are not able to reach a dynamic equilibrium state.The plateau surface is mostly underlain by soft rocks,such as the Mesozoic epimetamorphic argillites and Tertiary sedimentary rocks,while the mountain ranges comprise hard rocks,such as granite,gneiss and limestone.In soft rock regions,hills are low with a relative relief of mostly less than 100m and the slopes are gentle at a gradient of <20o.In contrast,hills can maintain steep slopes in hard rock regions.The Tibet Plateau has been under an equilibrium condition between tectonic uplifting and denudation except for the mountain ranges.The plateau might have reached the present altitudes before the Quaternary.

Studies of Metallic and Trace Minerals of the Tiegelongnan Cu-Au Deposit, Central Tibet, China

Electron probe micro-analysis(EPMA) and scanning electron microscopy(SEM) equipped with energy dispersive spectrometry(EDS) have been used to investigate the principal ore minerals and coexisting metallic mineral inclusions in polished thin sections from the Tiegelongnan deposit, which consists of a high-sulfidation epithermal system(HSES) and a porphyry system(PS). Molybdenite,chalcopyrite, bornite, tennantite, enargite, digenite, anilite, covellite, and tetrahedrite have been identified by EPMA. Intergrowth, cross-cutting and replacement relationships between the metallic minerals suggest that molybdenite formed first(stage 1),followed by chalcopyrite ± bornite ± hematite(stage 2),then bornite ± Cu-sulfides ± Cu-Fe-sulfoarsenides(stage 3),and lastly Cu-Fe-sulfoarsenides ±Cu-sulfides(stage 4). Pyrite is developed throughout all the stages. Droplet-like inclusions of Au-Te minerals commonly occur in tennantite but not in the other major sulfides(molybdenite, chalcopyrite and bornite),implying that tennantite is the most important Au telluride carrier. The pervasive binary equilibrium phases of calaverite and altaite constrain fin the range from ～-6.5 to ～-8 and f<-11.The intergrowth of bornite and chalcopyrite and the conversion from bornite to digenite suggest fluctuated and relatively low precipitation temperature conditions in the HSES relative to the PS.Contrastingly, the dominance of chalcopyrite in the PS, with minor bornite, suggests relatively high temperature conditions. These new results are important for further understanding the mineral formation processes superimposed by HSES and PS systems.

First Report of Avian Tracks from the Cretaceous of Tibet, China

Objective Despite a large number of bird fossils in the Jehol Biota, Mesozoic bird records from other parts of China are dominated by tracks. Late Cretaceous bird tracks are rarely found in China. Reliable reports so far include a Dongyangornipes and Koreanaornis assemblage of early Late Cretaceous age from Dongyang City, Zhejiang Province, China （Azuma et al., 2013）. Buckley et al. （2016） consider Dongyangornipes sinensis a subjective junior synonym of Uhangrichnus chuni. Type Uhangrichnus chuni （Yang et al. 1995; Lockley et al., 2012） from the Uhangri Formation, Hwangsan Basin of South Korea is Late Cretaceous in age, and the trackrnaker was a web-footed avian.

Study on Climate Impacts on Asphalt Pavement in Tibet, China

Differences in climatic conditions have a significant impact on the bearing capacity and performance of asphalt pavements. The climatic conditions in Tibet are complex. Therefore, it is necessary to establish a climate division of asphalt pavement in Tibet. In this paper, the meteorological data of 28 meteorological stations in Tibet from 1991 to 2000 were used to analyze the main climatic factors affecting the performance of highway asphalt pavement by cluster analysis. The results are as follows: 1) The main climatic factors affecting the performance of highway asphalt pavement in Tibet include: solar radiation, maximum temperature, minimum temperature and large temperature difference. 2) The climate zoning indicators are the average daily solar radiation daily maximum temperature, the average annual extreme maximum temperature, the annual extreme temperature, and the average annual maximum temperature for seven consecutive days. 3) Tibet can be divided into five climate zones of I-V. In summary, the geographical boundaries and indicator distribution ranges of each sub-district can provide reference for the construction of highway asphalt pavement in Tibet.

Economic Development in Tibet of China

On 18-28 September, 2003, Mr. Lomanov Alexandre, deputy director of international desk of the Vremya Novostej (News Times) of Russia, was invited to visit Tibet, China. Following is the article written by him and published in the Vremya Novostej (News Times) of Russia on October 13, 2003.

China's Tibet Readers and Friends Are Welcome to Visit Tibet

Many of our readers have been reading our magazine for years. But very few of them have been to Tibet.The landscape is number one in the world. It is highlighted by the Tibetan culture is unique.However, this is what is described in written language.What is Tibet really like? Is Tibet a region just as described by China’s Tibet?We sincerely invite our readers and friends to visit in order to see Tibet with their own eyes and talk to our editors.

China's Tibet Readers and Friends Are Welcome to Visit Tibet

Many of our readers have been reading our magazine for years. But very few of them have been to Tibet. The landscape is number one in the world. It is highlighted by the Tibetan culture is unique. However, this is what is described in written language. What is Tibet really like? Is Tibet a region just as described by China’s Tibet?

马先蒿属一中国新记录种——陈塘马先蒿

于西藏喜马拉雅南坡的陈塘沟开展植物多样性调查过程中,发现一种在《中国植物志》中未记录的马先蒿属(Pedicularis)植物。通过文献查阅和详细的形态学比较,确定其为中国新记录种Pedicularis tamurensis T.Yamaz.,为其新拟中文名称:陈塘马先蒿。该种以前仅发现于尼泊尔,现也发现于中国西藏自治区日喀则市定结县陈塘镇。此新记录种生长于海拔约2900 m的冷杉(Abies fabri(Mast.)Craib)林下,与光唇马先蒿(Pedicularis fletcheri P.C.Tsoong)相似,主要识别特征为:叶对生,两面均密生短毛,羽状全裂至深裂;花序总状,花白色,盔瓣呈镰刀状弯弓,中间渐狭成喙,顶端2裂,下唇完全包围盔瓣。本文对陈塘马先蒿进行了详细的形态描述,介绍了其分布信息,并提供彩色图片便于鉴别。该新记录种的发现更新了国产马先蒿属植物的资料,丰富了中国植物多样性的内容。

中国种子植物新资料

【目的】青藏高原因其特殊的地理位置、丰富的植被类型及复杂多变的气候条件,使其拥有独特而宝贵的植物资源。明确该地区植物本底资料及地理分布对本区域植物区系研究有着十分重要的意义。【方法和结果】文章以西藏自治区定日县嘎玛沟区域高山植物多样性及区系调查为基础,发现3个中国新记录种,即盔角马先蒿(Pedicularis cornigera T.Yamaz.)、细齿滇藁本[Hymenidium dentatum(DC.)Pimenov&Kljuykov]、噶穆兔耳草(Lagotis kunawurensis Rupr.)。【结论】文章对以上3个中国新记录种进行报道,对于研究该地区植物组成具有一定参考价值,同时为青藏高原植物多样性保护及植物系统分类补充新资料。

Response of Reactive Phosphorus Burial to the Sedimentary Transition from Cretaceous Black Shales to Oceanic Red Beds in Southern Tibet

The mechanism of sedimentary transition from the Cretaceous black shales to the oceanic red beds is a new and important direction of Cretaceous research. Chemical sequential extraction is applied to study the burial records of reactive phosphorus in the black shale of the Gyabula Formation and oceanic red beds of the Chuangde Formation, Southern Tibet. Results indicate that the principal reactive phosphorus species is the authigenic and carbonate-associated phosphorus （CAP） in the Gyabula Formation and iron oxides-associated phosphorus （FeP） in the Chuangde Formation which accounts for more than half of their own total phosphorus content. While the authigenic and carbonate-associated phosphorus （CAP） is almost equal in the two Formations; the iron oxidesassociated phosphorus is about 1.6 times higher in the Chuangde Formation than that in the Gyabula Formation resulting in a higher content of the total phosphorus in the Chuangde Formation. According to the observations on the marine phosphorus cyde in Modern Ocean, it is found that preferential burial and regeneration of reactive phosphorus corresponds to highly oxic and reducing conditions, respectively, leading to the different distribution of phosphorus in these two distinct type of marine sediments. It is the redox-sensitive behavior of phosphorus cycle to the different redox conditions in the ocean and the controlling effects of phosphorus to the marine production that stimulate the local sedimentary transition from the Cretaceous black shale to the oceanic red beds.

Changes in plant species composition and diversity of alpine Kobresia (Kobresia pygmaea) steppe meadow at different stages of desertification in the North Tibetan plateau

The impacts of desertification on the vegetation composition, structure, and species diversity of alpine Kobresia steppe meadow were evaluated in an area of severe desertification in Anduo County, Tibet Autonomous Region, northern China. We investigated and analyzed the floristic features of communities at four different stages of desertification (slight desertification [SLD], moderate desertification [MD], severe desertification [SD], and very severe desertification [VSD]). The composition and structure of the alpine Kobresia steppe meadow at the SLD site differed significantly from that at the MD, SD, and VSD sites. Species that were more drought resistant and inedible by livestock were the dominant species at the SD site. No plants were found in the shifting dunes of the VSD site. Species diversity also decreased with increasing desertification. The SLD site had the largest mean number of species and individuals and the largest richness index; the MD grassland had the largest Shannon-Wiener index and evenness index, but the smallest Simpson’s index. The vegetation cover declined from 91.8% to 34.8% as desertification increased from SLD to SD, and reached 0% in VSD areas with shifting dunes.