西北干旱地区凝结水试验研究

采用称重法,分别在非冻结期和冻结期,对不同土质的土样进行凝结水观测试验,分析讨论凝结水发生的条件、凝结水发生的时间、凝结水形成的主要影响因素、积雪条件下的凝结水、凝结水的数量及其变化以及凝结水的生态环境意义,研究成果对于认识干旱地区凝结水的形成机制及其生态环境意义具有重要价值.     

阿拉善高原地下水的稳定同位素异常

1987～1995年对降水、黑河水和古日乃草原地下水作了定位观测,在巴丹吉林沙漠水文探险中采集了沙漠和戈壁地下水及湖水.降水同位素组成δD～δ18O与Craig线相同,但发现了地下水的δD～δ18D关系平行于降水线且有氘盈余为负且达-22‰的异常,其成因不明.由地表、地下水环境同位素组成,分析了黑河治理规划实施后可能对地下水资源产生的工程影响,它近期不会成为古日乃草原沙漠化进程的因素,但对额济纳绿洲的影响却不容忽视.     

Response to climate change of different tree species and NDVI variation since 1923 in the middle arid region of Ningxia, China

The normalized difference vegetation index （NDVI） is used extensively to describe vegetation cover and ecological environ- ment change. The purpose of this study was to contrast the response of different tree species growing in the same habitat to climate change and retrieve past NDVI using tree-ring width data from tree cores collected from the transitional zone of Pinus tabulaeformis and Picea crassifolia in the Luoshan Mountains in the middle arid region of Ningxia. Correlation analysis indi- cated that radial growth ofP tabulaeJbrmis is more sensitive to precipitation and temperature change than that ofP crassifolia. Natural factors such as water availability and heat at this elevation are more suited to the growth ofP crassifolia, and are more advantageous to its renewal and succession. P. crassifolia is probably the better of the two species for protecting the forest ecosystem and conserving water in the Luoshan desertification area. Ring width of P. crassifolia correlates significantly with average NDVI for April-May （r =0.641, p 〈0.01）, and both of them are influenced positively by precipitation in April-May. The reconstructed NDVI for 1923-2007 shows the relatively low vegetation cover occurred in the 1920s-1930s, the 1960s-1970s, and the early 21 st century. The reconstructed NDVI better reflected the drought climate in the study area.     

Guidelines to Authors

1. Aims and scope
Sciences in Cold and Arid Regions （SCAR） is a bimonthly journal that publishes in English the latest research achievements in processes and the pattems of the Earth surface system in cold and arid regions. Researches in cold regions emphasize particularly on the cold-region-characterized physical,     

东疆红山Cu-Au矿床氧化带硫酸盐矿物穆斯堡尔谱特征及其意义

穆斯堡尔谱对确定铁离子占位、核外环境及氧化态方面有着独特的优势。在红山铜金矿床氧化带硫酸盐矿物的XRD、TA、湿法化学分析和红外光谱测试的基础上,测定了板铁矾、针绿矾等8种硫酸盐矿物的室温57Fe穆斯堡尔谱,并根据常温下硫酸盐矿物穆斯堡尔谱参数和其晶体结构中Fe3+和Fe2+的占据位置对其谱峰进行了指派。结果表明本矿床氧化带硫酸盐矿物的穆斯堡尔谱的同质异能位移较小、四级矩分裂值分布范围较大、无磁超精细分裂等特征,且硫酸盐矿物结构中存在着共价键。通过与青海锡铁山铅锌矿氧化带硫酸盐矿物的穆斯堡尔谱相比较,两者在近地表风化及氧化过程中所处的物理化学条件基本相同,酸性和氧化性的环境为硫酸盐矿物的产生和保存提供了良好条件,但红山矿床更为干旱少雨,导致两者硫酸盐的穆斯堡尔谱参数略有不同。     

罗布泊地区凝结水对潜卤水资源量评价的影响分析

新疆罗布泊地区属于极端干旱气候地区,大气降水对地下水的补给极其有限,长期以来,众多学者认为凝结水量是罗布泊干盐湖潜卤水的重要补给来源之一。本次通过在罗北凹地地区开展的凝结水试验,较准确地计算了其补给资源量,指出尽管研究区凝结水总生成量较大,但真正能入渗补给到潜卤水饱水带的量却极少,绝大多数凝结水都以难以开发利用的土壤水形式短暂保存,被蒸发散失到大气中,对潜卤水资源量评价影响较小。     

高密度电阻率法和激发极化法在抗旱找水定井位中的应用

针对河南省新乡市凤泉区严重缺水现状,利用高密度电阻率法、高密度电阻率法与激发极化对称四极测深组合在水文地质条件复杂的松散层和基岩干旱地区勘查地下水,结合水文地质资料和成井条件所定的井位,后经施工钻孔验证,定井成功率100%,解决了人、畜急需用水问题。通过以上两种方法结合或单一方法在该地区不同水文地质条件下的实际应用和应用效果分析,总结出针对该地区特定的水文地质条件选择高密度电阻率法、高密度电阻率法与激发极化法组合模式。密度电阻率法和激发极化法组合模式在该地区地下水勘查中的运用提高了地质解释的准确性和可靠性,值得在类似水文地质条件和地区推广应用。     

Provenance discrimination and Source-to-Sink studies from a dryland fluvial regime： An example from Kachchh,western India

Tracing the sediment delivery from its source terrain to its ultimate sink envisage multiple factors that play a vital role in understanding present day erosional engine.To accomplish this,it is significant to distinguish the variable end-members contributing to the basin.The findings from the study of dryland coastal fluvial regime in Kachchh(Western India),which is one of the end members contributing to the Gulf of Kachchh coast(partial sink) and finally to the Arabian Sea(ultimate sink) have been presented here.Multi-proxy sediment provenance proxies such as grain-size,clay minerals,geochemistry and magnetic minerals have been employed to evaluate the provenance discriminating characteristics of the Kachchh dryland fluvial system and factors influencing them.The results of different proxies indicate that the provenance signatures of uplands are quite characteristic with magnetic susceptibility(χ) values of 20×10~(-7)m~3kg~(-1) and smectite(S)/kaolinite(K) ratio between 0.26 and 0.49.The middle reaches show marked increase in magnetic mineral concentration with χ values(140×10~(-7)m~3kg~(-1))and S/K ratio(4.92),while the estuarine tract shows χ values(80×10~(-7)m~3kg~(-1)),S/K ratio(1.90) and,characteristic heavy minerals(i.e.mica minerals),probably reflect the interplay between land and sea oscillations.Major sources of sediments within catchment scale were identified,viz.,upland sedimentary rocks(Juran and Bhuj Formation sandstone-shale) and middle reaches volcanic(Deccan Trap Formation basalt) rocks.The present study draw cautions in provenance of sediment discrimination in areas influenced by Deccan basalt that has the overwhelming sediment delivery and a comparatively subdued effects of other provenance signatures.The studied proxies of mineralogy of clays,magnetic minerals and geochemistry of heavy and major elements serve as the potential for fingerprint of sediment source regions and hence behold a strong position in source to sink studies globally.     

极干旱地区土壤与大气水分的相互影响

基于建立在莫高窟窟顶的密闭拱棚,通过监测棚内凝结水量和空气温湿度,对极干旱地区典型极干旱气候条件下土壤与大气水分的相互影响进行综合分析。棚内凝结水量和空气温湿度的监测结果表明,在热动力作用下存在地下水分向大气输送的过程,其原因主要是在温度作用下土壤结合水分的分解蒸发与土壤盐分的吸湿吸附的交替作用。这也是形成所谓"土壤凝结水分"与"土壤水分呼吸"的根源。当温度升高时,土壤结合水分分解蒸发"呼出"水分,当温度降低时土壤盐分吸湿吸附,"吸入"大气水分,形成土壤与大气不对称水分交流。称质量实验表明:土壤水分的变化与空气温度的变化完全对应;有深层水分支持的土壤吸收大气水分的能力相对较差。极干旱地区土壤与大气水分的相互影响研究结果能为莫高窟珍贵文物的保护提供参考。