民勤盆地地下水水位下降特征与可持续利用评价

在水文地质调查的基础上，以地下水化学与同位素为基础数据，研究了民勤盆地地下水组成的琏本特征．自然演变规律和人类活动影响下的变化过程。地下水δ^18O较现代降水值低-3．5‰左右，表明民勤盆地地下水均为地质时期封存或入渗补给年代久远的古水，现代农业灌溉地下水是不可再生资源，大规模超采地下水导致地下水水位形成漏斗形曲面下降。作者以水量平衡理论为依据建立了估算地下水储量与农业经济规模灌溉可开采储量的“漏斗”模型，经计算绿洲浅层、深层地下水可开采静储量632亿m^3；绿洲浅层地下水淡水农业生产经济资源可开采总量为110亿m^3；按照目前开采速率，维持目前产业经济规模极限时问约为16．7a。因此，必须实施农业种植业经济向农业畜牧业、草业经济发展，以及产业调整期经济平稳过渡。     

Late Pleistocene and Holocene history of Lake Terrasovoje,Amery Oasis,East Antarctica,and its climatic and environmental implications

A 5.52 m long sediment sequence was recovered from Lake Terrasovoje, Amery Oasis, East Antarctica, in order to reconstruct the regional environmental history. The basal sediments, which are dominated by glacial and glaciofluvial clastic sediments, attest to a Late Pleistocene deglaciation of the lake basin. These sediments are overlain by 2.70 m of laminated algal and microbial mats and a few interspersed moss layers. Radiocarbon dating, conducted on bulk organic carbon of 12 samples throughout the organic sequence, provides a reliable chronology since the onset of biogenic accumulation at c. 12,400 cal. year BP. Successful diatom colonization, however, was probably hampered by extensive ice and snow cover on the lake and restricted input of nutrients until 10,200 cal. year BP. A subsequent increase of nutrient supply culminated between 8600 and 8200 cal. year BP and is related to warm summer temperatures and reduced albedo in the catchment. Warm conditions lasted until 6700 cal. year BP, supporting the establishment of a diatom community. Colder temperatures from 6700 cal. year BP culminated in several periods between 6200 and 3700 cal. year BP, when high amounts of sulphur and low abundances of diatoms were deposited due to a perennial ice and snow cover on the lake. During the late Holocene, relatively warm conditions between 3200 and 2300 cal. year BP and between 1500 to 1000 cal. year BP, respectively, indicated by high accumulation of organic matter and reducing bottom water conditions, were interrupted and followed by colder periods.     

民勤沙井子地区降水特征及干旱周期分析

利用民勤治沙综合试验站３４年（１９６１～１９９４年）降水的观测资料，对沙井子降水量、降水日数及其季节分配、降水强度、降水变率及降水保证率进行了统计分析，并采用降水变率和湿润指数（ＭＩ），应用最大熵谱方法（ＭＥＭ）对该区的干旱状况作出了周期分析     

运用系统动力学方法研究绿洲经济－生态系统──以玛纳斯绿洲为例

本文运用系统论的观点和系统动力学（ＳＤ）方法，剖析了干旱区绿洲经济－生态系统的特点及基本反馈结构；探讨了绿洲经济增长的内部机制及其与主要政策变量间的关系。应用模型的仿真结果，就玛纳斯绿洲经济发展的若干问题及人口承载力作了分析。     

The temporal change of driving factors during the course of land desertification in arid region of North China: the case of Minqin County

Taking the key research area in the arid region of North China—Minqin County—as a case, this paper analyzes the main factors impacting land desertification. Based on factor analysis method and the collection of data in the last 50 years, this paper researches the spatial changes of driving factors during the course of land desertification in Minqin, Gansu Province. The results of factor analysis indicate that the driving force of human factor on land desertification accounted for 56.33% in 1956–2004 and for 66.19% in 1981–2004, the driving force of nature factor on land desertification accounted for 11.29% in 1956–2004 and 8.11% in 1981–2004, and the synthesis of driving forces of human and natural factors accounted for 11.19% in 1956–2004 and for 14.88% in 1981–2004. This indicated that human driving force on land desertification was increasing in Minqin County gradually.     

基于信息扩散理论的干旱区农业旱灾风险分析——以甘肃省民勤县为例

 针对小区域历史灾情资料缺乏，获得的只是小样本数据，使用传统统计模型进行风险分析精度不高的特点，作者基于信息扩散原理，利用正态信息扩散技术将单一的样本观测值变为一模糊集的模糊数学方法，提出了农业旱灾风险定量分析模型，并以甘肃省民勤县为例，对干旱区农业旱灾风险进行了分析。计算结果表明，民勤的旱灾尽管年年发生，但农业受损程度并不大，受损程度主要集中在20%以内，受损程度在30%以上的可能性很小;但也不能忽视旱灾风险，受损10%以上旱灾发生概率在76%，结果符合实际。对信息扩散理论在现代风险分析技术中的应用提供了一个新途径。     

甘肃民勤绿洲北部荒漠区地下水水化学特征及成因分析

民勤绿洲北部荒漠区作为国家北方防沙带的重要组成部分以及石羊河下游生态保护治理区,在地下水水化学方面的研究程度很低。在野外调查、勘探及采样测试的基础上,综合运用数理统计、Piper三线图、离子相关性分析、Gibbs图及离子比例系数等方法对民勤绿洲北部荒漠区的地下水水化学特征及成因进行了研究分析。结果表明：研究区地下水溶解性总固体以及硬度值较高,水化学类型主要为Cl^-·SO₄^2--Na⁺型。地下水水质总体能够满足生态屏障区种植旱生、耐盐植被的需要。地下水水化学演化是由蒸发浓缩作用主导、风化溶解和阳离子交换共同作用的结果。地下水中超标的高硝酸盐氮水与牲畜粪便污染有关,高氟水的形成受原生地质环境背景影响。成果不仅进一步提高了区内地下水水化学的研究程度,亦可为民勤绿洲区保护、北方防沙带以及石羊河下游生态保护治理区建设提供科学依据。     

甘肃敦煌地区疏勒河尾闾区地下水化学特征及成因分析

疏勒河尾闾区是护卫敦煌绿洲及文化的生态安全屏障,但是对地下水化学的研究相对较少。本次研究在野外调查及采样测试的基础上,综合运用数理统计、Piper三线图、离子相关性分析、Gibbs图及离子比例系数等方法明确了疏勒河尾闾区的地下水化学特征,并对其成因进行了分析。结果表明：疏勒河尾闾区地下水水质总体呈弱碱性,具有高溶解性总固体及高硬度的特征,水化学类型主要为Cl-·SO2-4-Na+型。地下水水化学演化是由蒸发浓缩作用主导,同时风化溶解和阳离子交换共同作用的结果。地下水中的Ca2+及Mg2+主要来自于蒸发岩及硅酸盐的溶解,Na+主要来源于岩盐溶解。高氟水的形成与片麻岩中普遍存在的黑云母矿物、蒸发浓缩主导的水文地球化学作用以及地势低洼的地形条件有关。成果不仅丰富了疏勒河流域内的地下水化学研究,亦可为敦煌绿洲生态安全屏障区的保护与建设提供科学依据。     

Quantitative Analysis of Natural and Human Factors of Oasis Change in the Tail of Shiyang River over the Past 60 Years

The human and natural factors complicit in the driving forces of oasis change have always received considerable interest from the international research community. In this study, we used principal component analysis of natural and socio-economic statistical factors to quantitatively analyze the causal relationships and their contributions to the observed periodic expansion or shrinkage of the Minqin Oasis over almost 60 years. Our results show that human factors were the dominant factors governing expansion or shrinkage, with average contributions of 69.38% and 76.16%, respectively. Moreover, policy decisions have been the pivotal human factors. Under the influence of various policies, we have found that water resource utilization, land reclamation, population explosion, ecological protection and economic development have each played leading roles in different periods. This study provides a scientific basis for modelling the dynamics of an oasis for sustainable management.