论中国干旱区湖泊研究的重要意义

据最新统计,在中国年降水量小于200 mm的干旱区,有大小湖泊近400个,在我国3大自然地理区域,即东部季风区、西北干旱区和青藏高原区中居第2位.内陆湖泊不仅是干旱区气候的指示器,而且对内陆河流域生态与环境状况的反应极为灵敏.干旱区的湖泊是以流域为单元实现水分循环的重要环节,是自然和人类经济活动系统中的最后一个环节,其生物和生态系统最早对人类活动的干扰作出反应,第一个抗争也是第一个受害.国内外干旱区湖泊衰亡带来的灾难等事实告诉人们:保护湖泊水体,就是保护人类自己.人与湖泊水体和谐共处,是干旱区经济社会和人的全面发展不可缺失的重要条件之一,为此应该对湖泊状况实行监控,持之以恒进行系统研究.     

中国干旱区的湖泊

湖泊作为地表水的重要载体,参与自然系统的水分循环,这在世界干旱地区显得格外突出和重要.应用浏览软件(Google Earth),对2001-2005年中国干旱区湖泊进行判别,并结合有关实地调查资料得知,我国干旱区有大小湖泊近400个,其中,10 km2以上的有29个,10 km2以下的有334个,在我国3大自然地理区域中位居第二.开展干旱区湖泊的研究,对破解干旱区的气候变化和湖泊演变过程、形成特征,以及湖泊水生生物资源的科学开发利用和保护具有重要的理论和现实意义.     

人类活动对亚洲中部水环境安全的威胁

主要依赖河流出山口的径流量维系山地-绿洲-荒漠间脆弱生态平衡的亚洲中部干旱区,其水分循环过程完全不同于湿润区。平原区不产生径流,地表水和地下水同源于山区,一个流域就是一个以地表水和地下水相互依赖的生态功能单元,其中河流是纽带,连接山区径流形成区与平原径流散失区或消耗区,以水分循环为主体,并与生物、生态系统紧密相联系,构成一个独特而又完整的內陆水分循环体系。自然要素的变化,特别是人类的参与或介入,改变了水分循环的规律,对亚洲中部干旱区水和环境的形成具有很大的威胁。用多年的观测数据来讨论人类活动的影响,并提出维系和保持干旱区水环境的建议。     

干旱区绿洲农业生态系统特征及持续发展关键问题

本文论述了干旱区绿洲大农业（农、林、牧、副、渔）与人类的生态关系，及绿洲生态系统中物质与能量循环的特征，强调了草业与牧业在绿洲生态系统中的重要地位与作用。     

西北干旱区大气水分循环要素变化研究进展

西北干旱区是对全球气候变化响应最敏感的地区之一。全球变暖加剧水循环,引起大气水分循环要素发生明显变化。借助最新资料对过去50 a西北干旱区大气水分循环要素变化特征和相关科学问题进行了梳理总结,其主要结论:(1)西北干旱区水汽和降水量有一致性变化趋势,在20世纪80年代中后期突变型增多,21世纪初有微弱的减小态势。受季风强度减弱的影响,西北东部地区水汽和降水量减小明显。(2)降水量增加站点占到95.9%,形成了天山、祁连山等增湿中心,具有明显的增湿海拔依赖性特征。(3)实际蒸散发量呈微弱的减小趋势,天山山区明显减少,而祁连山地区明显增加。(4)干旱区西部夏季降水以西风带水汽输送为主,但大尺度大降水过程发生时,低纬水汽输送尤为重要。全球气候变暖在影响着大气水分循环要素明显变化的同时,也加剧了干旱区水循环过程和水资源的不确定性。     

干旱区内陆湖泊水盐变化及调控机理

根据干旱区内陆湖泊水量演化特征,基于一种新的湖泊分类方法,对不同类型的湖泊水量平衡原理进行分析,提出干旱区内陆湖泊的枯涸时间、枯涸指数概念,并给出其计算方法。采用质量守恒原理,结合湖泊"箱式"模型假定,推求湖泊水盐均衡规律,通过引入"相对稳定矿化度"、"蒸降入流比"及"蒸降出流比"等概念,分析湖泊的咸化时间及水盐近似均衡时间。以实例阐述干旱内陆湖泊生态恢复的调控机理,并为其提供理论依据。     

吉兰泰地区第四纪湖泊的演变

吉兰泰盐湖区是内蒙古干旱区内一个具有代表性的地区。本文在分析吉兰泰地区第四纪以来对称性空间地貌结构和特征以及沉积相的基础上,指出吉兰泰湖泊的演化,经历了从古大湖—古大湖分解—形成新内陆湖的持续收缩过程。通过与青藏、新疆和内蒙古等高原湖泊演化的对比研究。证明吉兰泰湖泊的发育明显受到新构造运动和宏观气候因素的综合控制。现代人为活动影响也十分强烈。     

西北干旱区土壤的生态特征与变化

本文利用详实的资料,分析了干旱区主要土壤类型、分布及其生态意义,土壤的理化性状、养分特征以及在盐碱化、沙化和灌耕条件下的变化,并论证了这种变化在生态功能上的影响。其结果表明：①干旱土壤分布具明显空间垂直地带性及径向分布规律。极端干旱条件下的暖温带棕漠土的生态功能最差,其他土壤的生态功能排序依次为灰棕漠土＜ 灰漠土＜ 灰钙土（棕钙土）＜ 灌耕土＜ 草甸土类;②土壤生态性能在灌耕,风沙及盐碱化条件下发生显著变化,耕灌条件下使高生态性能的土壤逐渐退化而低生态性能土壤有所改善;盐碱化和风沙化的结果使土壤贫瘠化和粗质化,生态性能严重退化;干旱区平原土壤的生态特征与变化规律决定了其具有潜在荒漠化倾向。对干旱区土壤和生态特性及其变化的认识,是干旱区水土资源合理利用与生态保护的基础     

雨季北京山区3种典型植物的水分来源

水分是植物生长、初级生产力形成以及生态系统稳定的主要控制因素。为了深入探讨在雨季降雨后侧柏（Platycladus orientali）、栓皮栎（Quercus variabilis）和荆条（Vitex negundo var.heterophylla）的水分来源,根据降水、土壤水、地下水及植物茎干水分同位素特征,采用直接对比法和多源线性混合模型（Isosource）开展系统研究。结果显示：① 在雨后,侧柏主要利用表层0~10 cm的土壤水分和80 cm以下的深层土壤水分,它们对侧柏的水分贡献率分别为35.8%和55.6%,而对中间层(10~80 cm)土壤水分的利用较少;② 栓皮栎的水分来源与侧柏相似,但是对深层土壤水分的利用率比侧柏大,而对浅层土壤水分的利用率比侧柏小,这两层土壤水分的贡献率分别为17.7%和77.2%;③ 荆条的水分来源比较复杂,但主要来源仍然是表层0~10 cm的土壤水分,表层水分对其水分的贡献率为46.6%,而且对其他土层水分都有利用;在雨后,土壤水分充足的条件下,不同物种间水分利用模式仍有差异,从而促进了对土壤水分的有效利用,缓解了半干旱区物种间的水分竞争,这对我国北方山区生态恢复物种选择具有重要的参考价值。     

基于MODS耦合的新疆玛纳斯河流域生态安全问题研究

干旱区山地-绿洲-荒漠系统（MODS）耦合关系,是在新疆山盆结构及水文循环共同作用下形成的,是内陆河流域生态系统稳定性和生态服务健康性的客观表达。用生态系统耦合原理、空间结构稳定性分析、土地类型及利用评价等方法,结合相关遥感影像分析,得出：绿洲开发改变了流域水文循环及水资源分配的有效性,圈层结构的脆弱组成-天然绿洲及过...     

新疆博斯腾湖水污染特点分析

通过实地调查和对监测资料的分析 ,对博斯腾湖水质污染的特点进行了讨论。结果显示 :(1)造成博斯腾湖水质污染的主要原因是大量农田排盐水入湖 ,导致湖水污染 ;(2 )博斯腾湖污染最严重的区域是黄水区 ,主要超标物是可溶盐、COD和氨氮 ;(3)污染物入湖量最大的时间是 7～ 9月 ,入湖污染物约占全年入湖量的一半 ;(4 )博斯腾湖水质的污染主要是几个大排水渠引起的 ,它们的排放量占全部排水渠排放量的 80 %以上。同时 ,根据博斯腾湖水污染的特点 ,提出了农业发展和水环境保护的具体措施。     

A general multi-objective programming model for minimum ecological flow or water level of inland water bodies

Assessment of ecological flow or water level for water bodies is important for the protection of degraded or degrading ecosystems caused by water shortage in arid regions, and it has become a key issue in water resources planning. In the past several decades, many methods have been proposed to assess ecological flow for rivers and ecological water level for lakes or wetlands. To balance water uses by human and ecosystems, we proposed a general multi-objective programming model to determine minimum ecological flow or water level for inland water bodies, where two objectives are water index for human and habitat index for ecosystems, respectively. Using the weighted sum method for multi-objective optimization, minimum ecological flow or water level can be determined from the breakpoint in the water index–habitat index curve, which is similar to the slope method to determine minimum ecological flow from wetted perimeter–discharge curve. However, the general multi-objective programming model is superior to the slope method in its physical meaning and calculation method. This model provides a general analysis method for ecological water uses of different inland water bodies, and can be used to define minimum ecological flow or water level by choosing appropriate water and habitat indices. Several commonly used flow or water level assessment methods were found to be special cases of the general model, including the wetted perimeter method and the multi-objective physical habitat simulation method for ecological river flow, the inundated forest width method for regeneration flow of floodplain forest and the lake surface area method for ecological lake level. These methods were applied to determine minimum ecological flow or water level for two representative rivers and a lake in northern Xinjiang of China, including minimum ecological flow for the Ertix River, minimum regeneration flow for floodplain forest along the midstream of Kaxgar River, and minimum ecological lake level for the Ebinur Lake. The results illustrated the versatility of the general model, and can provide references for water resources planning and ecosystem protection for these rivers and lake.     

近期新疆湖泊变化所示的气候趋势

由绿洲及其所在荒漠盆地平原与周边山地系统共同组成的新疆地域系统、是我国西北干旱区的主要部分之一。由于荒漠盆地平原系统不产生径流 ,因此 ,地表水、浅层地下水和泉水、湖泊都必然地以相邻的山地系统为供给水源地。从山地进入荒漠盆地平原的河流就成为主要供给渠道。博期腾湖、艾丁湖、艾比湖 1 995年以来 ,湖水水位明显升高 ,湖水面积的不断扩大 ,从湖泊水面面积的演变过程 ,主要水源变化 ,气温略微上升 ,降水显著增多诸因素综合系统分析 ,说明在全球气候背景下 ,区域气候和水文变化朝着有利新疆社会经济发展的方向演变 ,这种趋势将持续到 2 1世纪前 1 0年     

Lake surface area method to define minimum ecological lake level from level-area-storage curves

Lake level assessment is essential for the protection of ecosystem in shrunk or shrinking lakes. Minimum ecological lake level is the critical lake level below which there should be no human activities to further decrease the lake level, and this level can provide a certain protection for the lake ecosystem. Lake surface area method was proposed to define the minimum ecological lake storage as the breakpoint of the lake surface area-storage curve, where the curve slope equals to the ratio of maximum lake surface area to maximum lake storage. If the curve can be expressed as a simple analytical function, the minimum ecological lake storage can be calculated analytically. Otherwise, it can be calculated numerically using the ideal point method for an equivalent multi-objective optimization model that balances ecosystem protection and water use. Then the minimum ecological lake level can be estimated from the lake level-storage curve. Compared with available lake morphology analysis methods, the lake surface area method is superior in its definition of minimum ecological lake level, applicable range of lake morphology, and calculation complexity. The proposed method was applied to two representative lakes in China, including one freshwater lake (the Dongting Lake in Hunan province in Central China) and one saltwater lake (the Ebinur Lake in Xinjiang Uygur autonomous region in Northwest China). The estimated minimum ecological lake level for the Dongting Lake is 26.7 m, at which 31% of the maximum lake storage provides 87% of the maximum lake surface area. The result for the Ebinur Lake is 191.2 m, at which 24% of the maximum lake storage provides 54% of the maximum lake surface area. The estimated minimum ecological lake level balances the conflict between economical and ecological water uses, and can provide a relatively larger habitat for the lake ecosystem with relatively smaller lake storage. These results are rational compared with the results of other methods. The calculated minimum ecological lake level can be used in the protection of lake ecosystems and the planning and rational use of water resources in lake basins.     

亚洲中部干旱区湖泊的地域分异性研究

湖泊是干旱区气候与环境变化的敏感指示器,了解干旱区湖泊的空间分布和变化特征,有利于正确分析和评估气候变化和人类活动对干旱区水资源的影响。采用2010年的Landsat 遥感数据资料,对新疆、中亚五国及其毗邻高山地区的湖泊制图,并分析该区域内湖泊的数量、面积的时空分布特征。研究表明：① 2010年研究区域内大于0.01 km²以上的湖泊总数为30 952个,总面积为496 674.35 km²,其中哈萨克斯坦北部、阿尔泰山地区和昆仑山南麓是湖泊富集的地区。② 湖泊数量与湖泊面积呈幂指数关系,湖泊面积每升高一个10的量级,该量级内的湖泊数量下降4~6倍,湖泊面积增加1~2倍,与全球的湖泊分布相比,属于湖泊分布相对稀少的地区。③ 湖泊数量在纬度带的空间分布相对均一,大型湖泊集中分布在41°~44°、46°和48°~50°的纬度带上;低海拔地区的湖泊数量多,面积大,高海拔地区湖泊数量多,面积小;山区、河谷湿地和哈萨克斯坦北部草原湖泊数量多;荒漠区湖泊分布稀少。④近20 a来,高山地区湖泊与平原地区湖泊呈相反的变化模式,高山地区湖泊处于稳定或快速扩张态势,而平原地区的湖泊剧烈萎缩。     

Tectonic geomorphological characteristics for evolution of the Manas Lake

Owing to global climatic changes and human activities,the lakes have changed dramatically in the Junggar Basin of Xinjiang in recent 50 years. Based on the remote sensing images from Beijing Satellite No.1 in 2006 together with the measured topographical data in 1999 and other data since the 1950s,this paper analyzes mainly the features of landforms around the Manas Lake and the changes of feeding sources of the lake. The results are as follows:(1) Tectonic movement brought about the fundamental geomorphological basis for lacustrine evolution,and the Manas Lake is one of small lakes broken up from the Old Manas Lake due to tectonic movement and drought climate; the Manas Lake had existed before the Manas River flowed into it in 1915. The geomorphologic evidences for evolution of the Manas Lake include:(a) Diluvial fans and old channels at the north of the lake indicate that the rivers originating from the north mountains of the Junggar Basin had fed the Old Manas Lake and now still feed the lake as seasonal rivers; (b) The Old Manas Lake was fed by many rivers originating from the mountains,except for the Manas River,from the evidence of small lakes around the Manas Lake,old channels,alluvial fans,etc.; (c) The elevations of the alluvial and diluvial fans are near to the 280 m a.s.l. and all of the small lakes and lacustrine plains are within the range of the 280 m a.s.l.,which may prove that the elevation of the Old Manas Lake was about 280 m a.s.l.; (d) Core analysis of the Manas Lake area also indicates that the Manas Lake has existed since Late Pleistocene epoch. (2) Analysis on the feeding relations between the lakes and the lacustrine evolution shows that human activities are one of main driving forces of the lacustrine evolution in recent 50 years,and it is the precondition of restoring and maintaining the lacutrine wetlands in the study area to satisfy the feeding of the Baiyang and Manas rivers to the Manas Lake.     

1976-2009年青藏高原内陆湖泊变化的时空格局与过程

为了揭示近几十年来气候变化条件下青藏高原内陆现代湖泊的时空变化规律,在1976年、1990年、2000年和 2009年4个时段青藏高原内陆湖泊变化制图结果的基础上,重点分析流域内湖泊变化的时间过程和流域间湖泊变化的空间模式,并从气候要素变化、流域水源补给等方面探讨影响内陆湖泊变化的主要因素。结果表明：流域内湖泊总面积1970-1990年萎缩、1990-2009年扩张,1976-2009年呈现扩张的变化趋势,年均降水量和年均气温的变化趋势较好地解释了湖泊由萎缩到扩张的变化状况。从湖泊变化的空间格局来看,不同地域、不同流域的湖泊面积变化模式及其剧烈程度与流域内的水源补给方式有关,以雪冰融水补给的流域内湖泊总面积变化的剧烈程度远不及以冻融水补给为主的流域。因此,区域气候的变化是近几十年来高原内陆湖泊整体显著萎缩或扩张的主要原因,而流域水源补给的方式诠释了湖泊变化的区域差异。     

塔里木盆地盐分循环变化与调控

在人类活动影响下，干旱内陆盆地盐分循环发生了很大变化，河流尾闾湖的盐分积聚区域消失，农田排水使河水水质盐化加重。本文提出了干旱内陆盆地盐分循环的调控措施，目的在于控制盐分快速积累的恶性循环，为新时期土壤渍化治理的宏观控制提供依据。     

新疆平原绿洲环境变化与生态维护

干旱区陆地生态系统的稳定性主要受控于水分因素,绿洲环境变化既相互联系,又互相制约,但都有自身的生态系统特点和对人类服务的功能。对新疆平原地区绿洲环境的变化进行分析发现,人工绿洲扩大和发展、城镇绿洲兴起和开拓、天然绿洲缩小和维护的总趋势。因此,需要在以流域或盆地为单元,以水为纽带并受水资源条件的限制,对流域或盆地内的所有农业绿洲、城镇绿洲和天然绿洲等生态系统与荒漠生态系统进行总体的水资源消耗平衡与生态平衡规划,科学配置水资源,才能维护相互的依存关系,并使各类绿洲得到生态维护。