Spatiotemporal vegetation cover variations in the Qinghai-Tibet Plateau under global climate change

Empirical Orthogonal Function （EOF） analysis and the related Principal Components （PC） analysis are used to extract valuable vegetation cover derived information from the National Oceanic and Atmos-pheric Administration （NOAA-AVHRR）＇s Leaf Area Index （LAI） satellite images. Results suggest that from 1982 to 2000 global climate change has contributed to an increase in vegetation cover in the Qinghai-Tibet Plateau. The correlation between rainfall and LAI EOF PC1 and PC2 indicates that rainfall is the major climatic factor influencing interannual variations of average vegetation cover throughout the entire Plateau. However, annual mean vegetation cover trends in the Qinghai-Tibet Plateau are mainly out of phase with air temperature increasing, which is primarily responsible for nonsynchro-nous changes of vegetation cover. In the southern ridge of the Qinghai-Tibet Plateau, recent warming trends contribute to humid weather and favorable conditions for vegetation growth. By contrast, higher temperatures have led to arid conditions and insufficient rainfall in the northern part of the Plateau, leading to drought and other climatic conditions which are not conducive to increased vegetation cover.     

Projected change in extreme rainfall events in China by the end of the 21st century using CMIP5 models

Projection of future climate changes and their regional impact is critical for long-term planning at the national and regional levels aimed at adaptation and mitigation. This study assesses the future changes in precipitation in China and the associated atmospheric circulation patterns using the Couple Model Intercomparison Project 5 Phase (CMIP5) simulations under the RCP4.5 and RCP8.5 scenarios. The results consistently indicate that the annual precipitation in China is projected to significantly increase at the end of the 21st century compared to the present-day levels. The number of days and the intensity of medium rain, large rain and heavy rain are obviously increased, while the number of trace rain days is projected to decrease over the entire area of China. Further analysis indicates that the significant increase of annual precipitation in Northwest China is primarily due to the increase of light rain and the increases in North and Northeast China are primarily due to the increase of medium rain. In the region of southern China, the increases of large rain and heavy rain play an important role in the increase of annual precipitation, while light rain events play a negative role. Analysis of the changes in atmospheric circulation indicates that the East Asian summer monsoon circulation is projected to be considerably stronger, and the local atmospheric stratification is projected to be more unstable, all of which provide a background benefit for the increase of precipitation and extreme rainfall events in China under global warming scenarios.     

Elliptic curves in Huff’s model

In this paper,we present the generalized Huff curves that contain Huff’s model as a special case.First,it is proved that every elliptic curve with three points of order 2 is isomorphic to a generalized Huff curve.Then,the fast and explicit formulae are derived for generalized Huff curves in projective coordinates.This paper also enumerates the number of isomorphism classes of generalized Huff curves over finite fields.Finally,the explicit formulae are presented for the doubling step and addition step in Miller’s algorithm to compute the Tate pairing on generalized Huff elliptic curves.     

Acquiring synonymous attribute phrases for named entities via online encyclopedia

In this work,an approach is proposed to acquire synonymous attribute phrases of named entities （NEs） from an online encyclopedia.Synonymous attribute phrases are the phrases that express the same attribute with different surface forms for a class of NEs.Specifically,the proposed approach is composed of three stages.Firstly,the entries related to a given NE class are automatically selected from an online encyclopedia.Secondly,attribute phrases are extracted based on the statistics of phrase frequency.Thirdly,synonymous attributes are identified in a pairwise manner through a classification framework combining multiple features.The proposed approach is applied on Baidu Baike,a Chinese online encyclopedia,for four different NE classes.Experimental results show that the approach obtains an average precision of 74％ and an average F-value of 65％ for the four NE classes.In particular,thousands of synonymous attribute phrase pairs are acquired for each class,which demonstrates the effectiveness of the proposed approach.     

Large-scale low-frequency rainfall regimes and their transition modes in summertime over China

It is well known that the predictable period of daily weather is generally within 2-3 weeks, so spatio-temporal mean predictands have to be employed in the monthly, seasonal, and annual predictions. At present, rainfall patterns (RPs)[1-5] are the key for…     

Impact of urbanization on changes in temperature extremes in Beijing during 1978–2008

To quantify the impact of urbanization on changes in observed surface air temperature and extremes, a homogenized dataset of daily mean, maximum and minimum temperature （Trn, Trnax and Train） observations at 20 stations in Greater Beijing （GBJ） from 1978 to 2008 is analyzed. In contrast with previous studies, a cluster analysis is done to objectively classify observing stations into four categories （urbanized, suburban, rural and mountain）, which is checked with remote-sensing night-light images since the 1990s. At urbanized sites, there is an added warming trend in annual mean Tm representing an average of 10.9% （up to 18.4% or 0.12℃/decade at the most strongly influenced site） of overall warming. Corresponding contributions for Train are 12.7% （up to 20.8% or 0.19℃/decade） and 24% for diurnal temperature range DTR （up to 37.4% or 0.149℃/decade） over the last three dec- ades. Although it has not had a significant impact on daytime records （Tmax）, urbanization has enhanced the increasing （decreasing） trend of extremely warm （cold） nights by an average of 12.7% or 2.07 d/decade （29.0% or 5.06 d/decade） at the urbanized sites since the 1970s.     

Transboundary hydrological effects of hydropower dam construction on the Lancang River

Ecological and socioeconomic issues in the Greater Mekong Subregion have in recent years attracted increasing regional and global attention. Much of this concern has been centered on construction of a cascade of hydropower dams on the Lancang River （upper Mekong River） in southwestern China＇s Yunnan Province, This article uses monthly runoff data of hydrologic monitoring stations in the Lancang River watershed from the 1950s onward and key data of the partially completed 2-dam cascade on the main stream of Lancang River to perform a comprehensive analysis of possible transboundary hydrologic effects of dam construction on Lower Mekong River. Results of the analysis show the following： （1） changes in flows over the Lancang-Mekong river＇s 4880 km course are exceedingly complex, and the two existing dams on the mainstream of Lancang River are but one of many factors influencing those flows, not a major factor; （2） significant downstream impacts of the two existing dams are limited in scale to changes in daily flow stages, and are limited geographically to the narrow channel north of Vientiane; （3） over timescales of several days or more, the primary factor in flow changes is climate change; （4） below the Yunjinghong hydrologic station in Lancang River basin, flow volumes can be as great as 113.7×10^8 m^3, or 15.44% of the average annual total runoff out of China, now are not influenced by the dam construction. These results provide a scientific basis for reasonable assessment of transboundary impact of dam construction on the mainstream of Lancang River to the lower Mekong River.     

Relationship between precipitation and the infiltration depth over the middle and lower reaches of the Yellow River and Yangtze-Huaihe River Valley

The purpose of the paper is to extract and make the best use of rainfall information contained in the Chinese historical archives of Qing Dynasty, and reconstruct the precipitation series during 1736-1911. The study followed the Yu-Fen-Cun （rainfall infiltration depth） observation method in Qing Dynasty, to conduct soil infiltration experiment under the natural rainfall conditions during 2004-2006. The related parameters, such as precipitation, intensity, initial soil moisture content and infiltration depth have been measured at 10 stations （east of 105°E, 30°-40°N） with representative climatic conditions and soil physical texture in the middle and lower reaches of the Yellow River and Yangtze-Huaihe River Valley. The statistical results indicate that precipitation is the primary influencing factor to infiltration depth and is positively correlated with the infiltration depth. Additionally, the effects of every factor on infiltration depth are significantly different between the middle and lower reaches of the Yellow River and Yangtze-Huaihe River Valley. Finally, the relationship equations of precipitation and infiltration depth are established for each site, most of which can pass over 60% of the variance explanations and provide quantitative models to reconstruct the precipitation series using Yu-Fen-Cun records in Qing Dynasty.     

The influence of moderate ENSO on summer rainfall in eastern China and its comparison with strong ENSO

The 6 major ENSO events since 1979 are classified into the strong and moderate ENSO based on intensity. The composite analysis is performed to reveal the influence of ENSO on East Asian summer monsoon （EASM） and summer rainfall in eastern China. It is shown that the influence is changed with the seasonal cycle in summer, with a weaker influence in June and a stronger influence in August, indicating a long lagged effect of ENSO on EASM. Besides, the circulation and rainfall anomalies caused by the strong ENSO are also stronger with an earlier starting time, while the influence of the moderate ENSO is evident in August. The composite summer rainfall in eastern China for the moderate ENSO exhibits a northern rainfall pattern, which is totally different from the classical ENSO-type rainfall pattern. Based on the composite analysis, two moderate ENSO years with a similar intensity （i.e., 1995 and 2003） are compared. The result shows that, the response of EASM to the moderate ENSO during June and July is, to a certain degree, modulated by the circulation systems in mid-high latitudes of Eurasia and in the Southern Hemisphere, thereby inducing a different rainfall distribution in eastern China. In comparison with the strong ENSO in 1983, it is further revealed that, the strong ENSO plays a dominant role in summer rainfall anomalies in eastern China as well as in controlling the influence of the other factors on EASM. The strong ENSO is therefore different with the moderate ENSO.     

《梁山伯与祝英台》与《罗密欧与朱丽叶》调式比较

《梁山伯与祝英台》与《罗密欧与朱丽叶》两部作品的内容都取材于民间故事,都属于标题性音乐作品,作品曲式结构基本相同。不同之处是对造成悲剧原因的展示有着明显区别,主、副部主题的表现和运用截然相反,音乐的主基调有较大差异,作品的整体风格迥异。     

有氧运动与身心健康探析

健康与运动是密不可分的,运动分为有氧和无氧,有氧运动较无氧运动更易普及和被大众接受,从人体长期参加有氧运动对人的身体健康和心理健康的角度来阐述有氧运动对人体的良好影响。     

高校管理与师生权益的保护

当前,因高校管理引发的法律纠纷呈上升趋势,究其原因是师生的法治观念在增强,另一方面说明高校在师生管理等方面也存在诸多不适应。要改变这些不适应,就要进行依法治校,更新管理理念。做到规章制度合法、管理行为合法。努力加强法制教育工作和师德校风建设,切实保障师生的合法权益。     

博客与高校思想政治教育

网络的发展为我们带来全新便捷的互动平台和交流方式,博客是当今传播文化的重要载体,因个体性、公共性、开放性、成本投入少等特点吸引着"90后"大学生广泛关注。在新形势的要求下,高校辅导员应主动占领网络博客思想政治教育新阵地,加强辅导员博客建设,根据大学生的心理特点,利用博客提升网络思想政治教育工作的吸引力和感染力,创新高校思想政治教育。     

道教与魏晋南北朝文人的功利欲望

欲望是作家创作的内驱力,道教对中国古代文人的欲望有什么影响,这是研究中国古代文学和文学理论不能不思考的问题。本文从道教的功利性,文人纷纷走近道教,文学观念中的道教因素等方面,对道教与魏晋南北朝文人的功利欲望作些专门探讨。这无疑会拓展人们研究的新视界。     

文献信息情报工作在科技工作及立项决策中的作用

本文揭示了在当今信息市场形势下 ,文献信息情报工作在科技工作和经济立项决策中的作用 ,同时也指出 :图书馆文献信息工作者们能在强手如云的信息市场中占领一块阵地也应成为图书馆界的共识     

我国的沙暴、尘暴及其防治

 我国是沙尘暴易发的国家, 进入90年代以来, 沙尘暴有频率增加、强度加大、范围扩展、危害程度加剧的趋势。据统计, 我国发生强沙尘暴的次数, 50年代为5次, 60年代为8次, 70年代为13次, 80年代为14次[1], 90年代为23次[2], 呈明显上升趋势。沙尘暴的强度及造成的损失, 以90年代最为突出, 发生于1993年5月5日(5.5沙尘暴)和1998年4月16日(4.16沙尘暴)的特大强沙尘暴, 是我国近100年来所罕见, 损失极其惨重。     

我国的沙暴、尘暴及其防治

我国是沙尘暴易发的国家 ,进入９０年代以来 ,沙尘暴有频率增加、强度加大、范围扩展、危害程度加剧的趋势。据统计 ,我国发生强沙尘暴的次数 ,５０年代为５次 ,６０年代为８次 ,７０年代为１３次 ,８０年代为１４次［１］ ,９０年代为２３次［２］ ,呈明显上升趋势。沙尘暴的强度及造成的损失 ,以９０年代最为突出 ,发生于１９９３年５月５日（５．５沙尘暴）和１９９８年４月１６日（４．１６沙尘暴）的特大强沙尘暴 ,是我国近１００年来所罕见 ,损失极其惨重。５、５沙尘暴锋面前移速度１４～１７米／秒 ,最大１９．５米／秒 ,瞬时最大风…     

辽金诗文话语与佛禅

辽金诗文作品中存在着大量的由佛经禅典移植而来的话语。这一现象从特定侧面体现了佛禅对中国古代文学的渗透溶浸。其表现主要反映在借用佛禅意像、使用佛禅故实和引用佛禅语汇三方面。