Biodiversity and conservation in the Tibetan Plateau

The Tibetan Plateau (Qinghai-Xizang Plateau) is a unique biogeographic region in the world, where various landscapes, altitudinal belts, alpine ecosystems, and endangered and endemic species have been developed. A total of 26 altitudinal belts, 28 spectra of altitudinal belts, 12,000 species of vascular plant, 5,000 species of epiphytes, 210 species of mammals, and 532 species of birds have been recorded. The plateau is also one of the centers of species formation and differentiation in the world To protect the biodiversity of the plateau, about 80 nature reserves have been designated, of which 45 are national or provincial, covering about 22% of the plateau area. Most of the nature reserves are distributed in the southeastern plateau. Recently, the Chinese government has initiated the “Natural Forests Protection Project of China,” mainly in the upper reaches of the Yangtze and Yellow rivers. “No logging” policies have been made and implemented for these areas.     

Biodiversity and conservation in the Tibetan Plateau

The Tibetan Plateau (Qinghai-Xizang Plateau) is a unique biogeographic region in the world, where various landscapes, altitudinal belts, alpine ecosystems, and endangered and endemic species have been developed. A total of 26 altitudinal belts, 28 spectra of altitudinal belts, 12,000 species of vascular plant, 5,000 species of epiphytes, 210 species of mammals, and 532 species of birds have been recorded. The plateau is also one of the centers of species formation and differentiation in the world. To protect the biodiversity of the plateau, about 80 nature reserves have been designated, of which 45 are national or provincial, covering about 22% of the plateau area. Most of the nature reserves are distributed in the southeastern plateau. Recently, the Chinese government has initiated the “Natural Forests Protection Project of China,” mainly in the upper reaches of the Yangtze and Yellow rivers. “No logging” policies have been made and implemented for these areas.     

Atmospheric hydrological budget with its effects over Tibetan Plateau

1IntroductionThe Tibetan Plateau is the most prominent feature located at unique latitudes in the world and shows special dynamic and thermal effects, thus responsible for a conspicuous hydrological cycle in the atmosphere within Asian monsoon areas, and an extremely sensitive region of land-air interactions in East Asia. A lot of researches have dealt with Tibetan dynamic and thermal effects on atmospheric circulation (Ye and Gao, 1979; Zhang etal., 1988; Ye and Fang, 1999; Zheng etal., 2…     

Atmospheric hydrological budget with its effects over Tibetan Plateau

Based on 1961-2000 NCEP/NCAR monthly mean reanalysis datasets, vapor transfer and hydrological budget over the Tibetan Plateau are investigated. The Plateau is a vapor sink all the year round. In summer, vapor is convergent in lower levels (from surface to 500 hPa) and divergent in upper levels (from 400 to 300 hPa), with 450 hPa referred to as level of non-divergence. Two levels have different hydrologic budget signatures: the budget is negative at the upper levels from February to November, i.e., vapor transfers from the upper levels over the plateau; as to the lower, the negative (positive) budget occurs during the winter (summer) half year. Evidence also indicates that Tibetan Plateau is a "vapor transition belt", vapor from the south and the west is transferred from lower to upper levels there in summer, which will affect surrounding regions, including eastern China, especially, the middle and lower reaches of the Yangtze. Vapor transfer exerts significant influence on precipitation in summertime months. Vapor transferred from the upper layers helps humidify eastern China, with coefficient -0.3 of the upper budget to the precipitation over the middle and lower reaches of the Yangtze (MLRY); also, vapor transferred from east side (27.5o-32.5oN) of the upper level has remarkable relationship with precipitation, the coefficient being 0.41. The convergence of the lower level vapor has great effects on the local precipitation over the plateau, with coefficient reaching 0.44, and the vapor passage affects the advance and retreat of the rainbelt. In general, atmospheric hydrologic budget and vapor transfer over the plateau have noticeable effects on precipitation of the target region as well as the ambient areas.     

Geomorphic constraints on the active tectonics of southern Taiwan

Taiwan is a region of rapid active tectonics, yet the study of the tectonic processes that shape the interior of the island is difficult due to the high rates of erosion and dense vegetation. We use digital topography to look for indications of active deformation preserved in the local geomorphology. In particular, anomalies in the regional pattern of drainage are used to infer zones of enhanced tectonic activity. The apparent anticlockwise rotation of major river systems in plan view indicates the presence of a diffuse zone of left-lateral shear running down the southeastern side of Taiwan. Asymmetries in the catchments of individual drainage basins show the influence of varying rates of uplift across southern Taiwan, with the most rapid uplift close to Taitung at the indentation point of the Luzon arc with the Chinese continental margin. Our interpretations, though based predominantly on remote-sensing observations, are consistent with the available field evidence. This study demonstrates the usefulness of drainage basins as tectonic markers in the quantification of regional strain and uplift, which may have wider applicability in other deforming parts of the world.     

Statistics of cloud heights over the Tibetan Plateau and its surrounding region derived from CloudSat data

Cloud-radiation interaction has a large impact on the Earth's weather and climate change, and clouds with different heights cause different radiative forcing. Thus, the information on the statistics of cloud height and its variation in space and time is very important to global climate change studies. In this paper, cloud top height (CTH), cloud base height (CBH) and cloud thickness over regions of the Tibetan Plateau, south slope of the plateau and South Asian Monsoon are analyzed based on CloudSat data during the period from June 2006 to December 2007. The results show that frequency of CTH and CBH in unit area over the studied regions have certain temporal-spatial continuity. The CTH and CBH of different cloud types have different variation scopes, and their seasonal variations are distinct. Cloud thickness is large (small) in summer (winter), and the percentages of different cloud types also have certain regularity.     

青藏高原的气候植被模型研究进展

气候植被研究是全球变化研究的重要内容, 而模型研究是气候植被研究的重要手段。青藏 高原以其特殊的自然环境特点, 形成了气候与植被独特的适应机制, 为许多通用气候植被模型所 不能反映, 加之所受到人类活动的干扰相对较少, 决定其为植被气候研究的重要实验场地。本文 回顾了气候植被模型发展的相关历程, 评述了每类模型的特点及其不足。从植被格局研究和植被 生产力研究两个方面, 对青藏高原的气候植被研究进行了总结和分析, 认为模型研究是气候植被 研究的重要手段, 而青藏高原的研究在这方面还比较落后, 同时对青藏高原气候植被模型研究中 存在的一些问题, 如数据精度、模型的适宜性和结果验证等进行了讨论。认为今后青藏高原气候 植被模型研究的重点应是进一步明晰气候植被的关键过程, 立足高原环境特点开发有高原特色 的气候植被模型。     

论青藏高原范围与面积

长期以来 ,种种因素导致学者们对青藏高原确切范围的认识和理解存在差异。根据青藏高原相关领域研究的新成果和多年野外实践 ,从地理学角度 ,充分讨论了确定青藏高原范围和界线的原则与涉及的问题 ,结合信息技术方法对青藏高原范围与界线位置进行了精确的定位和定量分析。得出 :青藏高原在中国境内部分西起帕米尔高原 ,东至横断山脉 ,横跨 31个经度 ,东西长约 2 94 5km ;南自喜马拉雅山脉南缘 ,北迄昆仑山 -祁连山北侧 ,纵贯约 13个纬度 ,南北宽达 15 32km ;范围为 2 6°0 0′12″N～ 39°4 6′5 0″N ,73°18′5 2″E～ 10 4°4 6′5 9″E ,面积为 2 5 72 4× 10 3km2 ,占我国陆地总面积的 2 6 8%。     

青藏高原放牧强度空间化方法与应用

人类活动强度空间化是分析人类活动区域差异及其变化过程的基础,也是准确辨识土地变化驱动因素、合理调控人类活动的科学依据。当前人类活动强度研究多以数理方法对代用指标进行空间化,缺乏对人类活动机理过程的反映,也制约了人类活动强度空间异质性的展现。本文以青藏高原放牧活动为研究对象,在综合放牧喜好和草地管理策略的基础上,从放牧行为机理的角度,提出了区分放牧区与非放牧区的方法;以放牧密度衡量草地整体放牧压力,以放牧概率刻画放牧活动的空间差异,构建了区域放牧强度空间化模型。并以高原典型牧业县—泽库县为例,基于乡镇级牧业数据和自然地理基础信息进行了实证研究。结果表明：空间化结果较好反映了泽库县放牧强度的空间特征;直接指标的选取和客观的赋值方法提高了放牧强度空间化结果的准确性;比现有研究结果更能体现出县域内放牧强度的空间差异,且放牧强度变化过程与同期NDVI值变化具有较好的耦合性。本文为人类活动空间化方法研究提供了有益参考。     

青藏高原高寒区生态脆弱性评价

在分析青藏高原高寒生态系统形成机制的基础上,构筑了3个层次、10个指标的脆弱性评价指标体系,系统评估了青藏高原生态脆弱性及其区域差异。研究结果表明：青藏高原中、重度以上脆弱区的面积较大,占区域总面积的74．79％。微度、轻度脆弱区主要分布在雅鲁藏布江大拐弯处、藏东南海拔3000m以下的山地、祁连山南坡的西北段和昆仑山北...     

基于生态地理分区的青藏高原植被覆被变化及其对气候变化的响应

基于1982~2006年GIMMS NDVI数据集和地面气象台站观测数据,分析了青藏高原整个区域及各生态地理分区年均NDVI的变化趋势,并通过偏相关分析研究不同生态地理分区植被覆被变化对气温和降水响应的空间分异特征。研究表明:(1)近25年来,高原植被覆盖变化整体上趋于改善;高原东北部、东中部以及西南部湿润半湿润及部分半干旱地区植被趋于改善,植被覆盖较差的北部、西部半干旱和干旱地区呈现退化趋势;(2)高原植被变化与气温变化的相关性明显高于与降水变化的相关性,说明高原植被年际变化对温度变化更为敏感;(3)高原植被年际变化与气温和降水的相关性具有明显的区域差异,植被覆盖中等区域全年月NDVI与气温和降水的相关性最强,相关性由草甸向草原、针叶林逐步减弱,荒漠区相关性最弱。生长季植被覆盖变化与气温的相关性和全年相关性较一致,降水则不同,生长季期间高原大部分地区植被变化与降水相关性不显著。     

“Greatest lake period” and its palaeo-environment on the Tibetan Plateau

The “greatest lake period” means that the lakes are in the stage of their maximum areas. As the paleo lake shorelines are widely distributed in the lake basins on the Tibetan Plateau, the lake areas during the “greatest lake period” may be inferred by the last highest lake shorelines. They are several, even tens times larger than that at present. According to the analyses of tens of lakes on the Plateau, most dating data fell into the range of 40-25 ka BP, some lasted to 20 ka BP. It was corresponded to the stage 3 of marine isotope and interstitial of last glaciation. The occurrence of maximum areas of lakes marked the very humid period on the Plateau and was also related to the stronger summer monsoon during that period.     

青藏高原湖泊沉积研究及其进展

青藏高原湖泊沉积研究主要围绕青藏高原隆升和全球变化响应开展的。研究揭示了青藏高原隆升具有整体性、阶段性和后期加速性。中晚更新世以来和末次间冰期-冰期气候演化过程得到重建,并能够与冰芯和深海氧同位素记录对比;同时也存在M IS3阶段强烈暖湿和末次冰盛期冷湿等区域特征;新仙女木事件在湖泊沉积物也有明显记录。全新世研究表明青藏高原早期暖湿并经历冷事件,大暖期普遍出现高水位,后期气候向干冷化方向发展。湖泊沉积环境定量化重建也得到研究。青藏高原湖泊沉积应在高分辨率纹层沉积和环境指标定量分析基础理论方面加强研究。     

西藏高原近40年的气温变化

利用西藏1961－2000年月平均气温、最高气温、最低气温资料，分析了近40年高原气温的变化趋势。结果发现，西藏大部分地区四季和年平均气温为升温趋势，尤其是秋、冬季；高原上普遍存在气温非对称变化现象，以Tmax、Tmin显著上升，但Tmin上升幅度大于Tmax为主要类型。Tmax上升主要表现在夏季，增暖以冬季最为明显，气温日较差降夏季外均显著减小。在各纬度带上均表现为升温，春、秋季升温最大，冬季次之。高海拔地区比低海拔地区升温强。近40年来西藏高原年平均气温以0.26℃/10a的增长率上升，明显高于全国和全球气温的增长率。20世纪60年代多异常偏冷年，90年代多异常偏暖年。