1962—2019年锡尔河-咸海三角洲湿地时空变化及驱动因素

咸海周边环境变化对中亚干旱区生态稳定有重要影响,研究锡尔河-咸海三角洲湿地演变对认识流域生态环境变化、实施生态修复等具有重要意义。基于多源遥感数据采用面向对象分层提取法方法,分析1962—2019年锡尔河下游三角洲湿地的时空变化特征,并结合咸海变化、耕地变化、河流水量和水利工程建设等探讨近60a湿地变化的驱动因素。研究表明:①近60 a在咸海持续萎缩的情况下,锡尔河下游三角洲湿地呈现先减小后增加的变化趋势,其中1962—1980年、1981—1991年和1992—2019年3个阶段的变化率分别为-38.29 km2/a、193.35 km2/a和14.36 km2/a;②湿地变化有明显的空间差异,锡尔河南、北2个入湖口区的湿地自1980年以来向咸海湖区扩张明显,耕地混合区的湿地自1991年以来向河道两侧扩张;③ 1962年后在入三角洲径流量总体减少的趋势下,灌渠建设和生态用水配置是三角洲湿地面积增加的主要原因,间接导致咸海入湖水量减少,咸海快速萎缩。锡尔河三角洲湿地恢复与咸海干涸形成了明显的生态反差,不利于咸海周边生态的整体恢复。     

气候变化和人类活动对中亚地区水文环境的影响评估

中亚地区是我国天气的上游区,生态环境异常脆弱,必须要保证该地区生态环境和资源安全,水资源安全首当其冲.研究和评估气候变化和人类活动对中亚地区水文环境的影响,具有重要的战略意义.近百年来中亚地区气候有暖湿化趋势,气温增温持续时间较长且增温幅度较大,近50a增暖更加明显(0.47℃·(10a)^-1),其中冬季增温最快,预估未来会延续变暖的态势;同时20世纪80年代之后降水量持续波动上升.气候变化对该地区水资源的时空分布及湖泊变迁造成了重大影响,人类活动加剧了水资源短缺,近50a来锡尔河和阿姆河入咸海径流量均呈减少的趋势,20世纪70年代之后拦水蓄水水库等水利工程的建设,加上灌溉用水的增加,导致两河入咸海水量骤减;而1987年之后两河入咸海水量回升,主要是气温回暖、降水增多,加速了常年积雪和冰川融化,使得进入河道的径流量增加.同时,湖泊水位下降,面积收缩,水质恶化.中亚水资源问题主要是跨国水资源分配和水环境恶化问题,要做好水资源评估和用水规划工作,建立覆盖全区域的水资源环境监测网络.中亚国家需要共同参与制定一套完整的、综合考虑人口、社会经济、生态环境等因素的水资源管理政治立法决策体系,构建中亚各国人水和谐、互利共存的水资源新秩序,以水资源可持续利用来支持经济与社会的可持续发展.     

Investigations on Aral Sea Regressions from Mirabilite Deposits and Remote Sensing

Remote sensing techniques including radar (Topex/Poseidon, Jason-1 and Envisat) and laser altimetry (Icesat), and moderate resolution spectro-radiometer (MODIS) images, are used to estimated current level and surface extent time variations of the Aral Sea. During the Holocene several phases of regression occurred, leading to desiccation of the Aral Sea. During the last 50 years, Aral Sea has drastically shrunk due to intense use of river’s water for irrigation purposes. It is currently separated into four distinct water bodies, namely, the Small Aral in the North, the Tchebas Bay in the North West, and the South West and the South East basins. The Kulandy strait connected the SW and SE basins until very recent times. These basins are now almost separated and salinity becomes very high (140–180 g/l) in the Eastern part. Rubanov discovered past deposits of mirabilite in the years 1970–1980. We investigate the significance of these deposits in the light of current evolution of the four water bodies that constitute the heritage of Aral Sea contemporary desiccation. Using remote sensing techniques, we have attempted to calculate the water balance of south Aral Sea during the last 3 years. We conclude in strong probability that the Kulandy strait carries water most of the time from the Eastern Basin to the Western Basin. We have demonstrated that it should have been the same process in the past to explain the Mirabilite deposit, but unfortunately, due to recent artificial water monitoring of the Aral Sea (dam in the Berg’s strait, new reservoirs in the Amu Darya’s delta), it is impossible to make definitive conclusion from actual Aral Sea water balance.     

咸海流域水文水资源演变与咸海生态危机出路分析

中亚的咸海问题已成为全球性的生态和社会问题,研究咸海流域水文水资源、经济社会发展演变与气候变化,对深入理解中亚地区咸海危机形成机理、未来发展趋势、探讨咸海生态危机出路具有重要意义,对类似区域跨界河流和我国西北干旱区水资源开发利用具有重要借鉴意义. 介绍了中亚五国咸海流域的水资源及其开发利用情况,重点分析了中亚五国咸海流域农业灌溉的发展演变、近80a来咸海流域气候变化趋势与主要河流水文演变情势及咸海水文特征演变. 结果表明,咸海生态危机完全是由人类自导并日益严重的水资源-生态-环境与社会危机,短期内难以遏制,长期来看也无法逆转. 结合咸海危机生态环境效应,讨论了3个跨流域调水方案拯救咸海的利弊与前景,探讨了立足于流域本身拯救咸海的综合治理措施. 最后,提出了咸海危机经验教训对我国内陆河水资源开发利用的若干启示.     

国外水资源开发利用的经验教训

合理开发和利用水资源是西部大开发成功的关键。通过对美国水资源管理政策的演化及前苏联的“咸海生态灾难”的研究，总结其正反二方面的经验教训，以进一步提高水资源开发决策的科学性。     

A high-resolution diatom-inferred palaeoconductivity and lake level record of the Aral Sea for the last 1600 yr

Formerly the world's fourth largest lake by area, the Aral Sea is presently undergoing extreme desiccation due to large-scale irrigation strategies implemented in the Soviet era. As part of the INTAS-funded CLIMAN project into Holocene climatic variability and the evolution of human settlement in the Aral Sea basin, fossil diatom assemblages contained within a sediment core obtained from the Aral Sea have been applied to a diatom-based inference model of conductivity (r² = 0.767, RMSEP = 0.469 log₁₀ μS cm^− 1). This has provided a high-resolution record of conductivity and lake level change over the last ca. 1600 yr. Three severe episodes of lake level regression are indicated at ca. AD 400, AD 1195–1355 and ca. AD 1780 to the present day. The first two regressions may be linked to the natural diversion of the Amu Darya away from the Aral Sea and the failure of cyclones formed in the Mediterranean to penetrate more continental regions. Human activity, however, and in particular the destruction of irrigation facilities are synchronous with these early regressions and contributed to the severity of the observed low stands.     

The history of economic development in the Aral region and its influence on the environment

The current ecological crisis in the Aral basin is a result of a number of factors, including specific features of the history of economic activity of the local population. Interaction of sedentory farmers of oases and nomads of steppes and deserts was of the most importance. Periods of political centralization coincided with the rise and spread of irrigation-based farming, and vice versa, the reduction of irrigated areas occurred in troubled war and crises time. In modern times the total area of ancient irrigation lands in the lower reaches of Amu Darya and Syr Darya has mounted to 4,5 mln hectares. Complex archaeological study of these areas has made possible the reconstruction of complicated history of the development of irrigation and irrigation-based farming.     

Groundwater resources use and management in the Amu Darya River Basin (Central Asia)

This paper analyses groundwater resources use and management in the socio-economic context of the Amu Darya River Basin which covers a part of the following landlocked Central Asian countries: Afghanistan, Tajikistan, Turkmenistan and Uzbekistan. These agrarian nations for sustaining their vital agricultural productions started to use groundwater during the recent drought years (1998–2001) because of its relatively good quality and quantity and as an alternative to highly mineralized surface waters. Present extent of groundwater resources use is discussed with consideration to their reserves, quality, and institutional management and transboundary aspects within the basin. After the collapse of the centralized water resources management system and infrastructure of the former Soviet Union, new underdeveloped systems are being practiced over the whole Amu Darya River Basin. The critical situation of groundwater management in Afghanistan is also discussed. This work attempts to document the management and use of groundwater in the Amu Darya Basin and present time management realities, with fragmented and weak national and regional regulation on groundwater. Special attention is given to groundwater resources in irrigated agriculture, which increased use in all countries of the basin is due to quick access to underground resources and relatively good quality and quantity.     

中亚各国在咸海流域水资源问题上的冲突与合作

咸海流域是中亚社会发展进程中水资源供需矛盾和生态环境问题表现最为突出的区域,已严重妨碍了经济发展和社会稳定,甚至严重影响到中亚国家间的关系. 在解决咸海问题上,中亚各国虽然都表现出了极度忧虑和希望合作解决共同问题的诚意,签订了一系列的多边和双边合作协议,付诸了较多的行动;发达国家和国际组织也多方介入,大力援助、积极斡旋,但仍未从根本上缓解咸海危机. 深入分析介绍了咸海流域的水资源及开发利用情况、中亚各国在咸海流域水资源问题上的冲突以及开展的一系列合作,探讨了咸海危机的潜在水冲突,提出了合理利用水资源,实现流域一体化管理,化解咸海危机的对策措施.     

Global land water storage change from GRACE over 2002–2009; Inference on sea level

Global change in land water storage and its effect on sea level is estimated over a 7-year time span (August 2002 to July 2009) using space gravimetry data from GRACE. The 33 World largest river basins are considered. We focus on the year-to-year variability and construct a total land water storage time series that we further express in equivalent sea level time series. The short-term trend in total water storage adjusted over this 7-year time span is positive and amounts to 80.6 ± 15.7 km³/yr (net water storage excess). Most of the positive contribution arises from the Amazon and Siberian basins (Lena and Yenisei), followed by the Zambezi, Orinoco and Ob basins. The largest negative contributions (water deficit) come from the Mississippi, Ganges, Brahmaputra, Aral, Euphrates, Indus and Parana. Expressed in terms of equivalent sea level, total water volume change over 2002–2009 leads to a small negative contribution to sea level of –0.22 ± 0.05 mm/yr. The time series for each basin clearly show that year-to-year variability dominates so that the value estimated in this study cannot be considered as representative of a long-term trend. We also compare the interannual variability of total land water storage (removing the mean trend over the studied time span) with interannual variability in sea level (corrected for thermal expansion). A correlation of ∼0.6 is found. Phasing, in particular, is correct. Thus, at least part of the interannual variability of the global mean sea level can be attributed to land water storage fluctuations.     

咸海和巴尔喀什湖水文变化与环境效应对比

以咸海和巴尔喀什湖流域为研究对象,采用定性和定量分析相结合的途径,对两个湖泊的水文特征、主要补给河流的入湖径流特征、流域人类活动情况、生态环境问题及未来趋势等进行对比,分析咸海和巴尔喀什湖流域各方面的异同。研究发现:咸海的水位变化呈现相对单一趋势,从1960年开始急剧下降并于2009年分裂成4个水体;巴尔喀什湖的水位变化呈现明显周期性波动,从1970年开始出现下降并于1987年降至历史最低水位;目前的咸海仍不容乐观并将面临最终干涸,巴尔喀什湖正值丰水期并将进入枯水周期。在咸海和巴尔喀什湖两个跨界河流-湖泊流域的水资源和生态环境保护中,流域各国均负有重要责任。     

Ra-226 and Rn-222 in saline water compartments of the Aral Sea region

The Aral Sea has been shrinking since 1963 due to extensive irrigation and the corresponding decline in the river water inflow. Understanding of the current hydrological situation demands an improved understanding of the surface water/groundwater dynamics in the region. ²²²Rn and ²²⁶Ra measurements can be used to trace groundwater discharge into surface waters. Data of these radiometric parameters were not previously available for the study region. We determined ²²²Rn activities after liquid phase extraction using Liquid Scintillation Counting (LSC) with peak-length discrimination and analyzed ²²⁶Ra concentrations in different water compartments of the Amu Darya Delta (surface waters, unconfined groundwater, artesian water, and water profiles from the closed Large Aral Sea (western basin).The water samples comprise a salinity range between 1 and 263 g/l. The seasonal dynamics of solid/water interaction under an arid climate regime force the hydrochemical evolution of the unconfined groundwater in the Amu Darya Delta to high-salinity Na(Mg)Cl(SO₄) water types. The dissolved radium concentrations in the waters were mostly very low due to mineral over-saturation, extensive co-precipitation of radium and adsorption of radium on coexisting solid substrates.The analysis of very low ²²⁶Ra concentrations (<10 ppq) at remote study sites is a challenge. We used the water samples to test and improve different analytical methods. In particular, we modified a procedure developed for the α-spectrometric determination of ²²⁶Ra after solid phase extraction of radium using 3M Empore™ High Performance Extraction Disks (Purkl, 2002) for the analysis of the radionuclide using an ICP sector field mass spectrometer. The ²²⁶Ra concentration of 17 unconfined groundwater samples ranged between 0.2 and 5 ppq, and that of 28 artesian waters between <0.2 and 13 ppq. The ICP-MS results conformed satisfactorily to analytical results based on γ-measurements of the ²²²Rn ingrowth after purging and trapping on super-cooled charcoal. The ²²⁶Ra concentrations were positively correlated with the salinity and the dissolved NaCl concentrations. The occurrence of unusually high ²²⁶Ra activities is explained by radium release from adsorption sites with increasing salinity. The inferred spatial variability of ²²²Rn in the Aral Sea and of ²²²Rn and ²²⁶Ra in the groundwater of the Amu Darya Delta is discussed in the context of our own previous hydrochemical studies in the study sites. Relatively low ²²²Rn activities in the unconfined GW (1–9.5 Bq/l) indicate the alluvial sediments hosting the GW to be a low-²³⁸U(²²⁶Ra) substrate. Positive correlations between U and ²²⁶Ra, and U and ²²²Rn are likely related to locally deposited Fe(Mn)OOH precipitates. The ²²²Rn activity of the GW, however, distinctly exceeds the ²²²Rn concentration in the Aral Sea (10 mBq/l), in principle, making ²²²Rn a sensitive tracer for the inflow of GW. The high water volume of the Large Aral Sea and wind induced mixing of its water body, however, hamper the detection of local groundwater inflow.     

Water reservoirs, irrigation and sedimentation in Central Asia: a first-cut assessment for Uzbekistan

Water reservoirs play an important role in areas with limited and erratic precipitation where water is stored and re-distributed later for different purposes. Irrigation is primarily a major water consumer in arid countries of Central Asia for the economic development, employment and food security of the region. The major rivers of Central Asia (e.g., Amu Darya, Syr Darya, and Zerafshan) are turbid watercourses. Sedimentation reduces the main reservoir asset i.e., its volume capacity. In addition, vast territories of the region’s countries have been transformed for agriculture to grow water intensive crops such as cotton, rice and wheat during the Soviet Union that dramatically accelerated soil erosion by water and wind. Thus, many man-made water reservoirs are affected by high sedimentation rates. Moreover, uneven spatial and temporal water resources and a Soviet-inherited unified hydraulic infrastructure have raised transboundary reservoir management issues over water resources allocation among the countries in the region such as Kyrgyzstan, Tajikistan, Kazakhstan, Uzbekistan and Turkmenistan. The rivers such as Syr Darya and Amu Darya are already regulated by more than 78 and 94 %, respectively and attempts for new reservoir projects upstream raises increased concerns of the downstream countries (e.g., the Rogun hydropower station in Tajikistan and the Toktogul reservoir in Kyrgyzstan). For instance, the uncoordinated use of reservoirs has caused the Arnasai lake problem in Uzbekistan with environmental, material damage and social unrest. The aim of this paper is first to review the present conditions and the role of man-made water reservoirs for irrigation in Central Asia with special focus on Uzbekistan, second to document past and current reservoir sedimentation conditions in Uzbekistan and third to discuss research carried out by Soviet and present-time local research community in the domain of erosion and sedimentation in the region.     

Sub–fossil Ostracoda and the death of the Aral Sea

The Aral Sea has become increasingly saline since 1960, resulting in decimation of the aquatic biota. Of the 11 ostracod species known to have been alive in the Aral Sea 30 years ago, only one, the euryhaline Cyprideis torosa, lives there today. Recent research has suggested that this species has survived because it is capable of strong hypo–osmotic regulation. The Quaternary history of the sea shows that there have often been water–level fluctuations, but recent dramatic environmental changes have had particularly severe consequences on the ostracod faunas .     

阿姆河右岸B区中部卡洛夫-牛津阶高精度层序地层划分及层序发育模式

土库曼斯坦阿姆河盆地是世界上著名的大型含油气沉积盆地,然而目前盆地内卡洛夫—牛津阶的层序划分和地层对比依然存在争议。基于Vail经典层序地层学及沉积学相关理论,以阿姆河右岸B区29口井的岩心资料及50口井的测井资料为依据,结合地震、薄片、地球化学等手段,开展了阿姆河右岸B区卡洛夫-牛津阶的层序地层研究。将阿姆河右岸B区卡洛夫-牛津阶划分为5个三级层序和15个四级层序,其中卡洛夫阶包括2个三级层序(SQ1和SQ2),牛津阶分为3个三级层序(SQ3-SQ5)。在高精度层序划分的基础上,建立了研究区的层序地层格架,在垂向上,各级层序格架内部高位域生屑砂屑灰岩及礁滩体沉积更为发育;在平面上,根据不同层序沉积几何体和沉积相的分布,明确提出了卡洛夫期和牛津期发育两种不同的碳酸盐岩台地类型的观点：SQ1-SQ2时期(卡洛夫期)研究区应为缓坡型台地,初始具有西高东低的地貌,坡度较缓,沉积速率差别不大,主要发育缓坡台地层序地层模式;SQ3-SQ5时期(牛津期)则演化为镶边台地,研究区沉积速率远小于A区,随着海平面变化形成了差异巨大的西高东低沉积地貌。     

中亚干旱区的荒漠化与土地利用

笔者在实地考察、航片和卫星影像判读的基础上,参考国际上最新研究成果,以咸海盆地和古丝绸之路沿线地区为例,分析探讨了中亚干旱区荒漠化发生的过程、机制及其对自然和人文环境系统的影响和危害。由于大量从阿姆河和锡尔河引水扩大灌溉、浪费水源及单一农作物种植,使1960年时还为世界第四大湖的威海水面和蓄水大减,在干枯了的湖底和周围耕地上荒漠化快速发展,造成自然环境系统的严重退化和社会经济的巨大损失。虽然在我国丝绸之路沿线地区自古以来就有荒漠化现象,但荒漠化的规模在近40年来发生了根本性变化。塔里木河下游和克里雅河下游及玛纳斯河下游的湖泊干枯,植被退化甚至消失,不少野生动物灭绝。     

咸海演化的关键问题及其对经济、社会和生态价值的重要启示

本文回顾了Aral Sea(咸海)海平面变化的最新认识,以供社会和经济项目决策者使用。我们提出了咸海生态标准的新认识:由于1960年之前当时的人类活动已经引起了湖泊萎缩,咸海在1960年之前是小到中型湖泊,而不是大型湖泊。对咸海认识的改变可能会使许多基于极端情景的昂贵计划变得更加现实。同时,基于地质、考古、历史和水文研究中所获得的多重数据的综合分析,本次结果认为咸海在过去的2万年内经历了多次突然的海侵和海退。然而,除了现代的原因外,引起这些变化的原因的认识仍然不完整,需要进行专门的调查研究。在这篇论文中,我们针对水位变化、气候变化与咸海盆地来自锡尔河和阿姆河供水变化相结合的研究方法进行了讨论。     

Analysis of dynamic changes and influence factors of Lake Balkhash in the last twenty years

Lake Balkhash is the third largest inland lake in Central Asia after the Caspian Sea and the Aral Sea. The Ili River-Balkash Lake Basin resides in the southeastern part of the Republic of Kazakhstan and the western part of China's Ili Prefecture, which belongs to the arid and semi-arid region. In the middle to late 20th century, the Ili River-Balkash Lake Basin was affected by climate change and human activities, and the problems of water ecology and water resources became increasingly prominent, which became the focus of attention for China and Kazakhstan. In this study, the water level derived from radar altimeter data, the water surface area extracted from Landsat data, and the temperature and precipitation data in the basin were comprehensively utilised. Data analysis of the time course and correlation of hydrological, meteorological elements in the lake basin, water dynamic changes, and influencing factors of Lake Balkhash was studied. The results show that the cyclical change of regional climate is the main factor affecting the change of lake water, and human activities in the short term can regulate the change of water volume in Lake Balkhash. The research results in this paper can provide a scientific basis for the solution of water disputes in cross-border rivers between China and Kazakhstan.     

Analysis of dynamic changes and influence factors of Lake Balkhash in the last twenty years

Lake Balkhash is the third largest inland lake in Central Asia after the Caspian Sea and the Aral Sea.The Ili River-Balkash Lake Basin resides in the southeastern part of the Republic of Kazakhstan and the western part of China's Ili Prefecture,which belongs to the arid and semi-arid region.In the middle to late 20^thcentury,the Ili River-Balkash Lake Basin was affected by climate change and human activities,and the problems of water ecology and water resources became increasingly prominent,which became the focus of attention for China and Kazakhstan.In this study,the water level derived from radar altimeter data,the water surface area extracted from Landsat data,and the temperature and precipitation data in the basin were comprehensively utilised.Data analysis of the time course and correlation of hydrological,meteorological elements in the lake basin,water dynamic changes,and influencing factors of Lake Balkhash was studied.The results show that the cyclical change of regional climate is the main factor affecting the change of lake water,and human activities in the short term can regulate the change of water volume in Lake Balkhash.The research results in this paper can provide a scientific basis for the solution of water disputes in cross-border rivers between China and Kazakhstan.     

末次盛冰期以来河北平原第四系地下水流系统的演变

以区域自然地理及地质历史分析为基础,以环境同位素及大陆盐化咸水后期变化为实证依据,重塑了末次盛冰期以来河北平原第四系地下水流模式演变。研究发现,末次盛冰期以来河北平原第四系地下水流系统经历3个演变阶段:(1)距今18～15ka的低海平面时期,接受持续补给,地下水得到充分交替,发育穿透达到或接近第四系底界的区域水流系统;(2)距今15～12ka的海平面急剧抬升期,地形势差减弱,发育穿透第三含水层组的早期中间水流系统,与此同时区域水流系统趋于停滞;(3)距今2.5ka以来,现代河流地貌成形,高位河床与低位河床及河间低地的势差成为主要驱动力,发育穿透第一及第二含水层组的晚期中间水流系统。随着海平面抬升,后期发育的水流系统切割前期水流系统的一部分并叠置其上。因此,现今河北平原第四系的地下水流系统乃是不同演变时期地下水流系统的时空四维集合体。其他濒海平原,乃至侵蚀强度随时间减弱的内陆盆地,都有可能出现类似图景。距今12ka前后形成的大陆盐化咸水,由上升水流带到浅部,导致浅层咸水以及土地盐渍化,乃是河北平原水资源利用及生态与环境保护的关键性不利因素。