水资源约束下的阿克苏河流域适宜绿洲规模分析

阿克苏绿洲是中纬度干旱区典型的绿洲灌溉系统,制定绿洲适宜发展规模、明确适宜耕地面积,可为实现绿洲的生态稳定与可持续管理提供科学依据。以中国西北干旱区的阿克苏河流域为研究对象,基于作物需水量和绿洲适宜面积模型的水热平衡法,借助典型绿洲结构模型,计算了阿克苏绿洲的适宜耕地面积。结果表明：2010-2015年阿克苏灌区的作物需水量高达740.3 mm,较20世纪60年代的539.6 mm增加了37.2%;考虑到山区来水和下泄塔里木河干流的水量要求,阿克苏绿洲的可用水量为42.6×10⁸ m³;阿克苏河流域绿洲已处于不稳定状态,耕地面积超过了水资源承载能力。计算得出绿洲适宜规模为12 430 km²,与现有水平相当。基于作物需水量和绿洲适宜面积模型的水热平衡算法计算的阿克苏绿洲的适宜耕地面积分别为4 674 km²和4 211 km²,需要在当前耕地水平上退耕18%至26%。     

夏季不同天气背景和灌溉条件下绿洲地表辐射和能量平衡特征

利用2005年"绿洲系统能量和水分循环过程"野外观测实验(JTEX)资料,分析了夏季不同天气背景下的金塔绿洲小气候特征、辐射和能量平衡特征的日变化规律.结果表明:不同天气和土壤湿度背景下的辐射和能量平衡特征有较大差异.观测中发现有较大的能量不平衡差额,晴天时的能量亏损大于阴天的.     

绿洲耕地适宜面积确定与减灾研究——以新疆渭干河灌区为例

在干旱区,以农田为核心的绿洲规模过大,对绿洲的稳定性产生了广泛而深刻的影响。论文以位于塔里木盆地的渭干河为例,分析渭干河灌区当前所面临的主要风沙灾害,揭示了绿洲规模过大、农业耗水量过大。生态用水被侵占是导致农田生态环境恶化的重要原因。在此基础上,以水热平衡、水盐平衡理论分别计算了灌区适宜的规模与耕地面积。根据模型计算结果,提出了控制耕地规模、确保生态用水的宏观对策。     

Study on the oasis landscape fragmentation in northwestern China by using remote sensing data and GIS: a case study of Jinta oasis

The purpose of this study is to investigate the oasis landscape fragmentation in northwestern China’s arid regions. Landscape maps of Jinta oasis were compiled by using GIS based on Landsat TM data of 1990 and 2000. Landscape indexes for evaluating fragmentation are patch area, patch density, corridor density and split index. Results indicated many difference. First, between the years 1990 and 2000, the landscape fragmentation in Jinta oasis decreased slightly. Second, the area of the matrix decreased at the class level. The landscape fragmentation of the matrix (bare soil) increased as a result of increased influence of human activities on matrix and was opposite to the irrigated farmland whose area is larger and more aggregated in 2000 than in 1990. Third, dense corridor system is one of the most prominent characteristics of the arid regions. It is one of the key factors resulting in the landscape fragmentation; especially the fragmentation within the same patch types. The corridor density of irrigated farmland, residential area and forestland were quite large in Jinta oasis both in 1990 and 2000. The pattern of Jinta oasis is characterized by agricultural oasis embedded in Gobi and in the desert, where the ecosystem was disturbed strongly by the intense human activities.     

克里雅河绿洲的形成与演变

从８０００年前到现代，克里雅河流域孕育了原始绿洲、古绿洲、旧绿洲和新绿洲。旧绿洲是古绿洲的延续和发展，新绿洲是旧绿洲的扩大和外延。河流的自然改道，气候干旱和社会的长期动荡(战争)是促使河流下游古绿洲消亡的主要原因。在今后一段时期内，克里雅河上游地区的绿洲发展仍将是较缓慢的；中游地区的绿洲将进一步得到巩固和发展；下游地区的绿洲将向着退化的方向发展。     

关于中国西部干旱区生态环境演变与调控研究的思考

从中国西部干旱区的界定、自然条件特点的分析出发,结合国家西部大开发战略的实施,指出进行该区生态环境演变与调控研究的重大意义。提出了在时间序列上进行生态环境演变研究,在空间结构上开展生态系统结构、功能及生态过程研究,在时空耦合界面上探讨重大生态环境问题,进行生态系统的调控与管理研究的思路。并从生态环境形成演变、生态系统结构和功能、重大生态环境问题及生态环境管理等方面探讨了研究工作的技术路线。同时,指出了主要研究内容和需要解决的关键科学问题以及将要实现的研究目标。     

Construction of ecological environment of oasis in Qingtongxia Irrigation District

Oasis is the core area of social and economic development in the arid western regions, and is also a territory with prominent ecological environmental problems. Because of the unreasonable development and utilization of soil and water resources, the ecological environment of oasis in Qingtongxia Irrigation District is threatened by soil salinization, shrinkage of lakes and wetlands, and deterioration of water environment. As for these environmental problems, the direct cause is the loss of regulation of groundwater depth or serious pollution of water caused by man-made irrational exploitation, and the root cause lies in shortage of water resources and unreasonable allocation of water resources. In this regard, it is believed that the primary task for the construction ecological environment of oasis in Qingtongxia Irrigation District is to adjust the allocation structure of water resources and to ease the contradiction between supply and demand of water resources, for which the direct means is to carry out dynamic control of water and salt based on the ecological landscape structure and land type in the Irrigation District in accordance with local conditions.     

黑河中游金塔地区生态环境变化遥感监测

利用1990年和2000年的TM遥感资料,在经过定标、几何校正和图像增强等图像处理的基础上对土地覆盖类型进行解译,从而实现黑河中游金塔地区的生态环境遥感动态监测.从监测结果计算出黑河中游金塔地区2000年的生态环境相对于1990年的生态环境变化如下:人工用地增加34.17%,农业用地增加19.47%,水体增加8%,湿地增加6.3%,未利用土地增加了1.73%,自然/半自然植被减少42.78%.并对这些生态环境变化的原因进行了初步探讨。     

黑河下游额济纳绿洲退化规律及其控制因素

本文针对黑河下游的额济纳绿洲，借助遥感方法利用气象卫星数据定量确定了绿洲的多年动态变化规律，通过地下水数值模拟得到地下水水位埋深分布，提出植被覆盖率的概念较好地描述了植被生长状况与地下水位埋深的定量关系，最终给出了能从宏观上研究干旱区绿洲和水资源定量关系的实用方法。     

北疆玛纳斯河流域人工绿洲演变过程及其特点

利用历史文献资料、实地调查和监测资料, 并结合遥感影像解译数据, 分析了近2 000 a来玛纳斯河流域人工绿洲的演变进程, 探讨了人工绿洲扩展过程与水资源利用的关系以及绿洲扩张的特点. 结果显示: 近2 000 a来玛纳斯河流域人工绿洲的形成和演变可以分为4个时期: 17世纪以前以牧为主时期, 流域人工绿洲仅呈星点分布在交通要道和军事据点; 17世纪以后到1949年才进入半农半牧时期, 流域人工绿洲呈小块状分布在河、泉引水方便之处; 1949年以后玛纳斯河流域人工绿洲进入了以农为主时期, 人工绿洲由小片联接成大片, 扩大成新疆第四大绿洲群; 20世纪70年代以后城市化时期, 流域绿洲的二、三产业快速崛起.根据绿洲发展演变与水资源开发程度和灌溉水平将以农为主时期细分为4个阶段, 从4个阶段不同水利条件和灌溉水平下绿洲的规模可以看出人工绿洲的演变进程是与流域水资源利用水平紧密结合的; 玛纳斯河流域绿洲扩张的特点有: 人文因素对其有很大影响, 移民屯垦在绿洲发展中起了重要作用, 近60 a来人工绿洲面积成倍扩大, 尽管水利建设支撑绿洲发展, 但仍受到流域水资源的限制.     

中国西北地区额济纳绿洲植被盖度与黑河流量的滞后效应研究

干旱区植被生长与地下水的关系是生态水文地质学研究的热点之一。西北干旱地区,由于降水稀少,绿洲是当地人类生存和发展的主要依托。近年来,随着黑河流域中游地区用水量的逐年加大,下游来水量减少,使得下游额济纳绿洲的面积不断减小,湖泊干涸,沙漠化严重,生态环境恶化。由于绿洲植被的生长与水有极为密切的关系,因此,研究河流流量与绿洲植被生长之间的定量关系,对改善黑河流域生态环境、协调用水矛盾和合理配置水资源具有重要意义。将遥感数据与黑河径流量数据相结合,在区域尺度上定量研究额济纳绿洲植被生长与河流径流量的关系。结果表明,绿洲植被对黑河径流以及地下水有很强的依赖关系,而且黑河径流对额济纳绿洲的影响存在一年的滞后期,而地下水则通过这种滞后作用将两者联系起来。     

黑河地区鼎新戈壁与绿洲和沙漠下垫面地表辐射平衡气候学特征的对比分析

利用2006年2月至2007年1月在甘肃酒泉金塔地区进行的"绿洲系统能量与水分循环过程观测与数值研究"野外试验中鼎新戈壁下垫面地表辐射观测资料,对戈壁地区不同天气条件下和季节平均的辐射平衡特征进行了分析,并将其辐射平衡各分量的年变化特征与HEIFE实验区张掖和沙漠站1991年同期的辐射观测资料作了对比分析.结果表明:鼎新戈壁地区7月典型晴天下,其辐射各分量表现出了标准的辐射平衡的日变化形态,总辐射峰值达到1081 w·m-2,净辐射峰值也在650w·m-2以上;由于阴天和降水天气过程的影响,使7月平均的辐射特征与典型晴天相比,短波辐射减少了30%左右.辐射收支的季节差别非常明显,季节平均日积分值由大到小依次为夏季、春季、秋季和冬季,冬季的总辐射日总量不到夏季的一半,净辐射只有夏季的1/4多些;总辐射年总量达到6 500MJ·m-2以上,4月沙尘天气对这一地区总辐射有一定的影响.地表反射率整体表现为夏季小、冬季大,年平均值为0.241,比绿洲的大,而小于沙漠地区.而地面有效辐射却在夏季最大,冬季最小,年变化趋势与沙漠地区极为相近;春、夏、秋季有效辐射与吸收辐射之比在0.5左右,冬季增大到0.7以上,年平均分别为0.56,比沙漠的稍小而远大于绿洲地区;地表净辐射年变化与总辐射相同,年总量达到2 360 MJ·m-2,大于沙漠地区而比绿洲地区小很多.     

Re-evaluating the impacts of human activity and environmental change on desertification in the Minqin Oasis, China

The Minqin Oasis and its adjacent regions in northern China experienced significant desertification beginning 2,000 years ago and continuing to the present, and numerous studies have claimed that human activities, especially the flourishing of agriculture, have played a major role in environmental change in this region. Our analysis suggests that the observed desertification was mainly controlled by changes in the water component of the ecosystem and the arid climate. The impacts of cultivation on desertification from 2,000 years ago to the mid-1900s appear to have been relatively minor compared to the impacts of the area’s arid climate and its native geomorphological processes. Although human activity has increased from the late-1940s to the present, and the areas of the oasis reclaimed for agriculture have reached a maximum, desertification over the past 50 years appears to be a continuing process that began thousands of years ago, and is mainly controlled by decreasing water levels caused by the arid climate, local geomorphological processes and overuse of water in the upstream. Although both human activities and climate variation are important drivers of the desertification process, and it is not possible to completely separate the human influence from the climate impact, key factors on controlling desertification should be investigated before we place the blame solely on the flourishing of agriculture in this region.     

The changes of vegetation cover in Ejina Oasis based on water resources redistribution in Heihe River

The Ejina Oasis (EO), located in arid northwest China, is a typical arid area in the world. The ecosystem in the oasis has become worse since the 1990s. However, it began to improve after the Chinese government took the mandatory measure to redistribute the water in Heihe in 2000. To understand this change, the remote sensing images in 1990, 2000 and 2006 were selected, and exertion related Land Use/Cover Change (LUCC) model was employed. Results showed that: (1) non-vegetation cover was the main body of the vegetation cover in oasis, showing a trend of increase at the beginning and diminution later, while low, medium and high vegetation cover was the other way around; (2) the area of low, medium and high vegetation cover in 2006 was less than that in 1990; the status and trend index P _t of oasis vegetation cover was 0.62 in 1990–2000, which means that the oasis ecosystem of Ejina was getting worse and was under an unbalanced status; P _t was 0.27 in 2000–2006 indicating that the oasis ecosystem was restored obviously and the whole system tended to be balanced; (3) all of these changes should be attributed to the water resources redistribution in Heihe River, which played a leading role, as well as the measures and relevant policies taken by the local government, which promoted the rapid recovery of the medium and high vegetation.     

Land-use change and its environmental impact in the Heihe River Basin, arid northwestern China

Rapid land-use change has taken place in many arid and semi-arid regions of China over the last decade as the result of demand for food for its growing population. The Heihe River Basin, a typical inland river basin of temperate arid zone in northwestern China, was investigated to assess land-use change dynamics by the combined use of satellite remote sensing and geographical information systems (GIS), and to explore the interaction between these changes and the environment. Images were classified into six land-use types: cropland, forestland, grassland, water, urban or built-up land, and barren land. The objectives were to assess and analyze landscape change of land use/cover in Heihe River Basin over 15 years from 1987 to 2002. The results show that (1) grassland and barren land increase greatly by 22.3, and 268.2 km², respectively, but water area decreased rapidly by 247.2 km² in the upper reaches of Heihe River Basin; (2) cropland and urban or built-up land increased greatly by 174.9, and 64.6 km², respectively, but grassland decreased rapidly by 210.3 km² in the middle reaches of Heihe River Basin; and (3) barren land increased largely by 397.4 km², but grassland degraded seriously and water area decreased obviously by 313.3, and 21.7 km², respectively in the lower reaches of Heihe River Basin. These results show that significant changes in land-use occur within the whole basin over the study period and cause severe environmental degradation, such as water environmental changes (including surface water runoff change, decline of groundwater table and degeneration of surface water and groundwater quality), land desertification and salinization, and vegetation degeneracy.     

Oasis Functional Stability Evaluation Based on Multiple Indicators, Northwest China

We produced and analyzed oasis structure information, and evaluated oasis functional stability using the multiple indicators based on Remote Sensing (RS) and Geographical Information System (GIS) in the arid region of China in 2015. The results showed that the oases area was 193,734 km2, accounting for 8.17% of the arid region of China. The spatial difference in the functional stability of oases was obvious. The Beijiang zone had the highest functional stability and was relatively stable state, and the Hexi Corridor-Alashan Plateau zone had the lowest functional stability and was relatively unstable. The functional stability is dominated by production and ecological functions, which have regional differences. Increasing oasis agricultural output, strengthening highway infrastructure construction and paying attention to education will become important ways to improve oasis functional stability. Water resources determine the ecological function, thus affecting the oasis functional stability. The results provide references for the formulation of related policies according to local conditions.     

新疆开都-孔雀河流域绿洲需水量与稳定性分析

水是绿洲存在和发展的核心, 干旱区绿洲稳定性与水密切相关. 根据2000-2009年资料, 采用蒸发系数法和定额法估算开都-孔雀河流域绿洲自然生态系统和社会经济系统综合需水量, 并对水资源约束条件下的绿洲稳定性进行初步探讨. 结果表明: 2000-2009年, 绿洲年均总需水量理论值约为54.80×10⁸ m³, 其中开都河绿洲总需水量约为20.55×10⁸ m³, 孔雀河绿洲总需水量约为21.90×10⁸ m³, 博斯腾湖区耗水量约为12.35×10⁸ m³, 与绿洲10 a平均供水量相比, 供需表现出极大地不平衡性. 水资源可承载绿洲面积(不含博斯腾湖)约为3139.66 km², 其中可承载灌溉地面积约为1395.41 km², 与绿洲10 a平均面积5 248 km²相比, 差别较大, 绿洲处于不稳定状态, 现状绿洲面积应适当收缩. 最后, 对博斯腾湖最低生态水位进行讨论, 初步把大湖最低水位定为海拔1 045 m, 小湖最低生态水位定为海拔1 046.5 m.     

甘肃疏勒河冲积扇绿洲全新世孢粉组合和环境演化

通过甘肃疏勒河冲积扇九道沟下游剖面(JDG)沉积物系统的孢粉分析,探讨了这一极干旱区全新世植被和气候环境演化.约4.3 m厚沉积剖面的孢粉组合特征清楚地反映了研究区全新世植被经历了6个发展演替阶段,从老而新依次为:针叶林为主的针阔混交林-灌丛草原;灌丛草原;疏林灌木草原;针叶树为主的针阔混交林-灌丛草原;草原植被;针叶林-灌木草原.与植被发展演替相对应的气候环境经历了凉较湿→温干→暖湿→温较湿→温干→凉较湿的变化.这些结果对于了解该地区全新世气候演化以及中国西北干旱区未来环境预测方面都具有重要意义.     

中国西部干旱区生态环境演变与调控研究进展与展望

国家重点基础研究发展规划项目"中国西部干旱区生态环境演变与调控研究"实施 2年来,在古气候重建和环境变化,绿洲的演变规律与驱动力,绿洲水盐平衡与主要水文过程,绿洲生态系统的结构、生态过程与稳定性,山地、绿洲、荒漠三大生态系统耦合机理,生态景观演变规律及其对气候变化的响应,重大工程行为的生态环境效应,荒漠化成因及时空分布等研究方向和内容上取得了重要进展。在此基础上,项目后 2年的研究重点将继续以绿洲安全机制研究为核心,在时间序列上,重点研究近 2 000年来绿洲的形成演变规律,特别是近百年及近50年来西部干旱区气候变化与绿洲形成演变的关系,定量辨识绿洲发展演化的驱动力;在空间结构上,阐明绿洲格局的动态过程,深入探明山地、绿洲及荒漠生态系统耦合关系、绿洲生态系统稳定性机理与安全、高效、持续发展模式等;结合西部大开发工程建设和产业发展的进程,研究开发重大工程的生态环境效应,建立不同类型的生态建设示范区;配合国家重大工程时段,对西部干旱区生态环境演变趋势进行预测,提出生态系统的调控体系和管理模式,为西部开发和可持续发展服务。     

Study on Water Internal Recycle Process and Mechanism in Typical Mountain Areas of Inland Basins,Northwest China: Progress and Challenge

The water resource and its change of mountainous area are very important to the oasis economic system and ecosystem in the arid areas of northwest China. Accurately understanding the water transfer and circulation process among vegetation, soil, and atmosphere over different hydrological units in mountainous areas such as snow and ice, cold desert, forest and grassland is the basic scientific issue of water research in cold and arid regions, which is also the basis of water resource delicacy management and regulation. There are many research results on the hydrological function of different land covers in mountain areas, basin hydrological processes, however, there are only very limited studies on the water internal recycle at basin scale. The quantitative study on the mechanism of water internal recycle is still at the starting stage, which faces many challenges. The key project “Study on water internal recycle processes and mechanism in typical mountain areas of inland basins, Northwest China” funded by National Natural Science Foundation of China will select the Aksu River and Shule River Basin, which have better observation basis, as study area. The internal mechanism of moisture transfer and exchange process of different land cover and atmosphere, the internal mechanism of water cycle in the basin, and water transfer paths in atmosphere will be studied through enhancing runoff plot experiments on different land cover, analyzing the mechanism of water vapor transfer and exchange between different land covers in the watershed by isotope tracing on the water vapor flux of vegetation water, soil moisture and atmospheric moisture, improving the algorithms of remote sensing inversion and ground verification on land surface evapotranspiration on different land cover, and analyzing the water vapor flux from reanalysis data, and the coupling modeling of regional climate model and land surface process model. At last, the effect of different land cover in hydrological process of mountain area, and the impact of land cover on downstream oasis will be systematically analyzed.