内蒙古中西部地面感热通量影响沙尘暴的观测分析

利用内蒙古中西部不同地表类型的16个测站2005—2006年3—5月逐小时地面观测资料和逐日沙尘暴资料,计算了地面感热通量、地面位温并分析它们与沙尘暴的关系,结果发现:在内蒙古中西部春季地面感热通量表现为净加热,且沙尘暴发生次数多的年份净地面感热加热强度反而较小。在沙尘暴发生前,沙漠区和高平原区地面感热通量达到最大,而丘陵和平原地区反而开始降低。对于沙尘暴发生前12 h累积的地面感热加热强度及导致的地面位温上升幅度,高平原和丘陵平原区要强于沙漠区。但相对而言,沙漠和高平原地区地面感热加热影响沙尘暴的“效率”更高。     

春季东亚副热带西风急流的变化特征及其与中国沙尘天气的关系

利用欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts, ECMWF)提供的ERA-Interim全球大气再分析资料及1980-2012年中国北方逐月沙尘暴发生日数资料, 研究了春季东亚副热带西风急流(70°-120°E)的变化特征及其与中国春季沙尘天气之间的关系。结果表明:1980-2012年春季中国上空急流轴存在北移的趋势, 急流中心略向东移, 急流相对强度随年份增强, 与春季沙尘暴发生总站日数的年际变化呈显著负相关。春季沙尘暴多发年, 东亚副热带西风急流有所减弱, 而在哈萨克斯坦东部、蒙古国、中国内蒙古大部分地区及南疆地区等沙尘源地, 200 hPa纬向风速增大; 500、850 hPa风速、位势高度差值场的分布都有利于中国沙尘源地地面风速增大。在中国沙尘源地, 高层西风风速增大, 动量下传, 引起地面大风, 从而容易产生沙尘暴。     

中国沙尘暴分布规律及研究方法分析

在分析中国沙尘暴研究现状的基础上,对其时空分布规律、沙尘源地、移动路径、研究方法和手段进行了系统的总结。结果表明,中国沙尘暴分布与北方的沙漠、沙地、戈壁等荒漠化地区分布一致,存在4大沙尘源区。干枯的湖泊、弃荒土地、沙砾草场可能成为东北地区的主要沙源,应引起注意;沙尘暴移动路径主要有3条,分别归纳了各路径的特征;根据沙尘源区示踪方法的特点和实例,指出了适用条件和应用范围,为今后沙尘暴的研究和防治提供依据和思路。     

新疆沙尘暴天气的气候特征

根据地面观测资料,整理出1961-1999年39 a新疆90个气象观测站的沙尘暴天气现象资料并进行统计分析,给出新疆沙尘暴的时空分布特征,并以分钟为单位得到沙尘暴的日变化和持续时间。结果表明:①新疆沙尘暴的地理分布特点是北疆少南疆多、山区少盆地多,高发区在南北两大沙漠中,沙漠南缘、山脉北麓出现的沙尘暴多于其他周边地区。②沙尘暴的高发年代多在60年代和70年代,90年代沙尘暴的出现日数明显减少。③沙尘暴主要出现在4~8月,10月到次年3月少有沙尘暴发生。多发时段在16~21时,持续时间北疆一般不超过60 min,南疆一般不超过90 min,塔里木盆地南部沙尘暴的持续时间最长。     

中国沙尘天气的区域特征

利用筛选的1954~2000年中国338个站沙尘天气资料及相关气候资料,从沙尘天气区划方面着重分析研究了我国沙尘天气的区域特征。结果表明： 1) 我国沙尘天气多发区分别位于以民丰至和田为中心的南疆盆地和以民勤至吉兰泰为中心的河西地区。不同类型沙尘天气的空间分布范围不尽相同,其中沙尘暴主要发生在与北方沙漠及沙漠化土地相联系的极干旱、干旱和半干旱区内。扬沙和浮尘天气除了在沙尘暴发生区的绝大部分地区出现外,还向其它邻近地区扩展,如扬沙可向东北地区和东南的黄淮海平原及以南地区扩展;而浮尘天气则主要向东南方向扩展,可涉及整个黄淮海平原和长江中下游地区。相比之下,上风方向的中高纬地区,如北疆和东北北部地区,浮尘天气发生甚少。2) 全国沙尘暴天气易发区可划分为北疆、南疆、河西、柴达木盆地、河套、东北和青藏等7个亚区。沙尘暴和浮尘在南疆区发生日数最多,而扬沙在河西区发生日数最多。     

西北地区气溶胶的源和汇与沙尘暴研究综述

西北地区是我国沙尘暴发生次数频繁、发生强度最大的地区,近年来发生的大沙尘暴源地均位于新疆、甘肃和内蒙古的干燥沙漠或戈壁地带。由这些地区起源的沙尘既对全球气候有影响,又对全球化学物质的循环有重要意义。该地区荒漠化严重,已成为全球四大沙尘暴高发区之一的中亚沙尘暴区的重要组成部分,文中综合论述了中国西北地区沙尘气溶胶的源和汇与输运过程,概括性总结了近20多年来对西北地区沙尘暴的研究成果。     

内蒙古中西部沙源地影响沙尘暴扩展过程的数值模拟研究

 通过对2002年3月18—22日沙尘暴过程进行的数值模拟及针对内蒙古中西部沙尘源地影响的敏感性试验研究，结果表明, 内蒙古中西部荒漠化草原生态的迅速恶化是2001年前后沙尘天气的频繁发生的部分原因。由于沙源地海拔高度的不同和风速随高度的变化，在沙尘远距离输送过程中可能出现两个不同高度而相互孤立的优势沙尘输送带，分别位于对流层和地面附近。其传输距离、传输速度、影响地区、影响时间存在巨大差异。内蒙古中西部沙源地的起沙主要通过地面附近的沙尘输送带向东、向南传输。其通过对流层的传输随沙尘区的不断扩展而越来越弱，进而被其他更高海拔高度的沙源地起沙所取代。     

南疆沙尘暴气候特征分析

根据新疆地面气象记录月报表,整理出1961-1999年39a南疆42个气象观测站的沙尘暴天气现象资料并进行统计分析,给出南疆地区沙尘暴的时空分布特征。结果表明:①南疆沙尘暴的高发区在塔克拉玛干沙漠,沙漠南缘高于其它周边地区;②沙尘暴的多发年代在20世纪70年代,90年代沙尘暴的发生明显减少;③沙尘暴主要出现在3~8月,最活跃的是4~6月;④塔里木盆地全天都有沙尘暴发生,主要是在2~6时、11~15时、19~24时三个时段,其它地区在15~22时;⑤塔里木盆地周边地区多数沙尘暴持续时间在25h以内,其它地区大多数沙尘暴持续在30min以内。沙尘暴的最长持续时间盆地周边超过20h,其它地区在10h之内。     

宁夏盐池地区沙尘暴发生特征的统计分析

利用盐池气象站沙尘暴历史观测资料，从沙尘暴发生频次、灾害类型分型等几个方面进行了统计和研究。在对沙尘暴灾害强度聚类分析的基础上，对影响宁夏盐池地区的沙尘暴灾害进行了危害强度客观分类，并分析了该区沙尘暴历史变化和年、月、目的不同时间尺度变化。结果表明，宁夏沙尘暴年发生次数有减少的趋势，但发生1～2次特强沙尘暴的概率明显增多；沙尘暴强度与造成沙尘暴天气的天气系统、起沙源地和位置密切相关。沙尘暴分为西北气流型、锋线型、局地中小尺度大气型。特强沙尘暴的沙源地可能在腾格里沙漠、乌兰布和沙漠和巴丹吉林沙漠等更远的沙源地，强沙尘暴源于毛乌素沙地、乌兰布和沙漠、腾格里沙漠或巴丹吉林沙漠。弱至强沙尘暴可能与盐池南部荒漠化草场植被破坏和沙漠化有关、属就地起沙类型、不能造成特强沙尘暴灾害。     

欧亚大气环流对中国北方夏季沙尘天气的影响

根据1960-2010年全国701个地面站沙尘天气观测资料分析了中国夏季沙尘天气的空间分布和年际变化,发现南疆和内蒙古两个沙尘源区的夏季沙尘指数51年来均呈现出减小的趋势。通过分析夏季沙尘指数典型高、低值年环流场发现：500 hPa高度场上强烈发展的高原-贝加尔湖平均脊和减弱的东亚大槽,减少了高空低值系统对南疆和内蒙古中西部地区的影响,地面场上“北负南正”的变压场分布使得两个地区西风和西北风减小,最终导致夏季南疆和内蒙古地区沙尘天气减少。沙尘指数高值年时影响两个地区天气系统的差异在于：影响南疆地区的天气系统主要是高空的西路冷空气和地面场上发展的南疆热低压,而影响内蒙古地区的则是北路和偏北路冷空气以及地面场上强烈发展的蒙古-内蒙古热低压。     

Visceral Pedagogy: Teaching Challenging Topics Emotionally as Well as Cognitively

This article explores the pedagogical implications of students' embodied and emotional reactions to difficult course material inside and outside of the classroom. Scholarship on teaching typically focuses on dimensions of students' cognitive engagement and development, yet geographical coursework often involves emotionally fraught topics: environmental cataclysm, poverty, inequality, oppression, (ill) health, etc. Instructors who anticipate their students' emotional experiences will be able to better engage with and use these experiences toward learning goals. Some topics may be most effectively taught through emotionally activated learning activities, prompting reflection on the role of visceral learning experiences in higher education.     

日本政府主导型旅游发展模式及其政策措施与成效

旅游发展模式主要分为市场主导型和政府主导型。日本政府在发展入境旅游、出境旅游以及国内旅游时采取政府主导型旅游发展模式,根据不同旅游发展阶段的特点,通过制定法律,实施积极的财政金融政策以及必要的税收调节政策,加强国际旅游合作,制定和实施旅游产业的发展战略和产业政策,促进日本旅游业稳步发展。日本政府主导型旅游发展模式已经取得显著成效。     

Public Intellectualism as Assemblage

This article responds to Alderman and Inwood's call for geographers to engage in public intellectualism. Geographers have long been underrepresented among the ranks of public intellectuals, even as the discipline has fostered many and diverse traditions of robust critical explanation. The lens of assemblage theory on civic engagement efforts in Athens, Georgia, offers insight into how a democratically inclined public intellectualism might be temporarily achieved.     

Migration as Spatial Interaction

Abstract

The migration process is presented through the use of a movement model. The model described is a heuristic device that can be used by (1) teachers to point out the salient factors involved in migration, or (2) by researchers as a guide to theory formulation. The behavioral aspects of the decision to migrate are discussed in a spatial interaction framework. Numerous research efforts are put in a logical geographical structure for classroom presentation.     

论水土流失与土壤侵蚀及其有关概念的界定

水土流失、土壤侵蚀、水土保持等是水土保持学科和山区园土整治的常用概念，但长期以来对这些概念的解释可谓五花八门，即便正规教材、词（辞）典、知识性普及读物也是如此，这种状况极不利于山区水土流失防治工作的开展。本文在对土壤侵蚀过程、水土汉失内涵、土壤侵蚀量与流失量计量单元等关键性问题进行探析、并对现有国内外对这些概念的种种解释进行评述基础上，从水土保持的根本目的、特殊任务以及《水土保持法》的精神实质出发，按通俗性、大众性和可操作性的要求，对水土流失、土壤侵蚀、水土保持等基本概念进行了合理、可行的界定，得出了一些基本认识和体会，愿有助于山区水土流失防治工作的正常开展和水土保持学科的健康发展。     

Oil as a finite resource

Fossil fuels are finite and nonrenewable. In due course, they will become scarce and costly. Their role in powering modern economies is so vital as to warrant a review of ultimately recoverable reserves and of plausible future consumption patterns. Over the past 50 years, many oil companies, geologists, governments, and private corporations have performed scores of studies of Estimated Ultimately Recoverable (EUR) global oil. Taken together, the great majority of these studies reflect a consensus that EUR oil reserves lie within the range of 1800 to 2200 billion barrels. Given this range, a simple model is used to calculate that world oil production is likely to peak sometime between 2007 and 2019. The global transportation sector, almost totally dependent on oil, could be especially hard hit unless vehicles fueled by sources other than petroleum are developed and rapidly deployed.     

Assessment as a Diagnostic Tool

Abstract

This paper introduces the development and validation of the Test of Geography-Related Attitudes (ToGRA). The ToGRA measures student attitude on four discrete scales: 1) leisure interest in geography; 2) enjoyment of geographic education; 3) career interest in geography; and 4) interest in place. The ToGRA was validated from a field test sample of 388 ninth-grade World Geography students who responded to the Web-based instrument. Statistical analyses were performed on these data in order to enhance the overall scale characteristics and to determine construct validity. The resultant survey is the first validated affective-trait measurement instrument available to secondary-level researchers and practitioners.     

Geography as it is Examined

Book reviewed in this article:
SCHOOL CERTIFICATE GEOGRAPHY QUESTIONS. Edited by C. M. Herbert     

Epiphytic diatoms as flood indicators

The hydroecology of floodplain lakes is strongly regulated by flood events. The threat of climate warming and increasing human activities requires development of scientific methods to quantify changes in the frequency of short-lived flood events, because they remain difficult to identify using conventional paleolimnological and monitoring approaches. We developed an approach to detect floods in sediment records by comparing the abundance and composition of epiphytic diatom communities in flooded and non-flooded ponds of the Peace-Athabasca Delta (PAD), Canada, that grew on submerged macrophytes (Potamogeton zosteriformis, P. perfoliatus) and an artificial substrate (polypropylene sheets) during the open-water season of 2005. Analysis of similarity tests showed that epiphytic diatom community composition differs significantly between flooded and non-flooded ponds. After accounting for the “pond effect,” paired comparisons of the three substrates determined that variation in community composition between the artificial substrate and macrophytes was similar to that between the macrophyte taxa. Similarity percentage analysis identified diatom taxa that discriminate between flooded and non-flooded ponds. The relative abundance of ‘strong flood indicator taxa’ was used to construct an event-scale flood record spanning the past 180 years using analyses of sedimentary diatom assemblages from a closed-drainage pond (PAD 5). Results were verified by close agreement with an independent paleoflood record from a nearby flood-prone oxbow pond (PAD 54) and historical records. Comparison of epiphytic diatoms in flooded and non-flooded lakes in this study provides a promising approach to detect changes in flood frequency, and may have applications for reconstructing other pulse-type disturbances such as hurricanes and pollutant spills.