土壤水分监测仪器监测精度研究

土壤含水量是干旱区旱情分析不可缺少的水文要素。准确监测干旱区土壤含水量对旱情分析、灾害评估、抗旱决策具有重要意义。如何快速、准确测取土壤含水量是摆在墒情监测工作者和监测仪器生产厂家面前亟待解决的问题。结合墒情监测工作实际,针对提高土壤水分监测仪器的监测精度进行了探索和研究,提出了建设性意见。     

基于Landsat-8数据的镇赉县干旱监测研究

选取吉林省白城市镇赉县为研究区,通过遥感影像获取归一化植被指数、增强型植被指数、归一化水分指数和土壤调节植被指数,分别构建相应的植被指数-地表温度特征空间并计算其温度植被干旱指数,用野外采样点的受灾程度和面积数据进行验证。结果表明,不同土壤类型的地表温度存在差异,在植被旺盛期,基于归一化植被指数的温度植被干旱指数具有较高的旱情监测精度,可有效地用于大范围的干旱监测。     

土壤墒情监测仪器拟合公式研究

土壤墒情监测迟迟不能实现自动化,主要原因是墒情监测仪器的监测精度始终停留在只能定性地监视旱情的变化趋势,无法用自动监测数据准确分析出不同的干旱等级和计算出对应的受旱耕地面积。结合吉林省墒情监测工作实际,开展了土壤墒情监测仪器拟合公式的研究,提出了土壤墒情监测仪器拟合公式的最佳形式,对于仪器厂家转变观念,改变仪器公式形式,提高仪器监测精度,早日实现墒情监测自动化具有很好地参考价值。     

基于地表温度与植被指数特征空间反演地表参数的研究进展

遥感反演的地表温度(Ts)和植被指数(VI)构成的特征空间结合模型分析可以对显热通量、潜热通量及土壤含水量等地表参数进行估算.这种方法比较实用,且不过多地依赖地面观测数据.随着研究的深入,许多学者在Ts/VI特征空间基础上提出了更加丰富的空间变量.基于此,以不同空间变量为标准,分类介绍在Ts/VI特征空间的基础上对地表能量通量及土壤水分等参数的反演.其中包括在Ts/NDVI特征空间基础上提出温度植被干旱指数和条件植被温度指数来监测干旱;利用Ts/albedo特征空间反演蒸发比;用DSTV/VI特征空间反演蒸散量;用地气温差/植被指数特征空间反演蒸散量等.并介绍了Ts/VI特征空间与微波遥感结合反演地表含水量等相关研究的进展情况,最后提出未来研究的发展方向.     

基于植被指数和土地表面温度的干旱监测模型

干旱是一种周期性发生的自然现象,其发生过程中有关参数如地表覆盖度、温度和土壤表层含水量等可以通过遥感的途径进行定量反演,而这些参数客观地反映了地表的综合特征。综述了运用遥感反演产品---土地表面温度和归一化植被指数在干旱监测中的应用前景和进展,分析了距平植被指数、条件植被指数、条件温度指数和归一化温度指数等干旱监测方法的优缺点,在前人研究的基础上,提出了条件植被温度指数的干旱监测模型,探讨了其应用前景。     

卫星遥感信息系统在林火及干旱监测中的应用

根据几种投影方式的特点，再结合贵州地理位置，采用麦卡托投影方式来进行火灾检测，火灾自动监测系统能迅速找出火点位置并计算火面积，监测范围广，时效较常规地面监测手段提前1－3天。旱情的遥感监测基于土壤水分和植被状况，对于裸地卫星遥感重点是土壤的含水量，对于有植被覆盖的区域，遥感的重点是植被指数的变化以及植被冠层蒸腾状况的变化。从贵州的实际情况和地表条件，分别选用植被指数法、第四通道遥感下垫面温度法、植被供水指数法及热惯量方法来进行干旱监测。通过实例认为，气象卫星确实能大范围地对干旱进行宏观监测，其监测面积精度高，不仅可以迅速准确确定受灾面积，而且还可精确到县，在实际运用中可操作性很强，能为政府部门抓好防旱抗旱提供详细的数据参考，做好灾情预报和指导抗灾救灾工作服务。     

土壤水分与干旱遥感研究的进展与趋势

对土壤水分和干旱遥感监测的国内外发展情况进行了回顾,依据土壤水分和干旱遥感监测的原理,围绕着可见光与近红外、热红外、微波光谱波段的使用,分别以土壤和植被为观测对象,对国内外土壤水分与干旱遥感现状与发展趋势进行讨论。重点对微波遥感土壤湿度的算法发展和研究趋势进行了较详细的论述。在总结国内外土壤水分遥感监测研究实验中所用过的方法与原理的基础上,对目前遥感监测土壤水分研究领域的重点、难点和未来的发展方向进行了评述。土壤水分遥感监测是一个复杂的间接过程,波段及变量选择、传感器的性能等因素对土壤水分监测是至关重要的,土壤的各种理化性状、地形的分异作用以及气候变化和人为的土壤管理措施对土壤水分均有不同的影响,地表特征与土壤水分也存在着一定的相关性。改进的热惯量法和作物缺水指数法是当前土壤水分遥感监测中较为成熟的方法。GIS技术的广泛应用、土壤水分遥感监测模型的优化。微波遥感的应用将是该领域的重点研究方向。     

不同地表覆盖条件下区域水分盈亏的遥感分析——以中国北方为例

依据能量平衡和水分平衡原理，建立不同地表覆盖条件下的区域缺水计算方法，实现了利用遥感数据对我国北方缺水状况的宏观监测和快速反应。模型的具体步骤是：首先，利用NOAA/AVHRR数字影像进行地表覆盖分类，结合气象数据建立区域实际蒸散模型，并利用经联合国粮农组织修正的Penman公式计算区域潜在蒸散量。然后，由区域实际蒸散量和潜在蒸散量，构造出反映区域缺水程度的缺水指数。最后，利用该方法对1999年7月我国北方的区域水分盈亏状况进行了研究，讨论了区域缺水指数与土壤墒情、背景环境参数、地表覆盖类型的关系。     

整合陆地表面温度与植被指数信息进行地表覆盖变化研究

利用植被指数(NDVI)的多时相或时序资料进行地表覆盖研究已取得了大量成果。随着陆地表面温度(LST)遥感反演精度的不断提高,将LST与NDVI结合起来进行地表植被动态变化的监测已成为可能。选择我国北方草地及其东南部毗邻的农牧交错带(farmingpastoralzone)为研究区。该区位于内蒙古高原东南边缘和黄土高原北部,半干旱气候,经纬度范围为:35°～50°N,100°～125°E。     

基于MODIS数据的西藏干旱自动监测系统实现的关键技术研究

干旱是一种危害较大的自然灾害, 影响范围大、持续时间长. 随着经济发展和人口的增加, 水资源短缺现象日益严重, 这也导致了干旱范围的扩大和干旱化程度加重. 为降低业务人员负担, 提高业务工作效率, 探讨了基于MODIS遥感数据的西藏干旱监测系统实现的关键技术. 首先, 阐述了MODIS 轨道数据快速投影处理的正向投影处理技术原理, 然后分析了温度植被干旱指数算法(TVDI)及其实现, 最后, 将干旱监测方法集成到业务系统软件, 最终实现西藏全区的干旱遥感监测业务工作. 通过与传统手工干旱监测方法进行对比, 发现干旱自动监测系统具有速度快、自动化等优点, 具有十分重要的实践意义.     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

Définition d'une limite multicritère ; stratigraphie du passage Campanien–Maastrichtien du site géologique de Tercis (Landes,SW France)Definition of a multi-criteria boundary; stratigraphy of the Campanian–Maastrichtian interval of the geological site at Tercis (Landes,SW France)

Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

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GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)