Sediment suspension events in the inner surf and swash zone. Measurements in large-scale and high-energy wave conditions

The present study presents a database of hydrodynamic properties and suspended sediment concentration collected within the inner surf and swash zones aiming to improve the current understanding of the sediment dynamics occurring within the beach area closest to the shoreline.     

盐池湾自然保护区喜马拉雅雪鸡的巢址选择

2005年的4～7月,采用样方法和直接观察法,对甘肃省盐池湾自然保护区喜马拉雅雪鸡(Tetraogallus himalayensis)的巢址选择进行了研究.共测量16个巢址.研究表明,喜马拉雅雪鸡的巢主要分布于3 301～3 500 m之间、多在灌丛草地和高山岩石草地、灌木下或草丛中及突出大石下、中坡以上的坡位、坡度...     

2021年5月22日青海玛多M7.4地震前共和水温异常分析研究

2021年5月22日青海省玛多县发生M7.4地震,震前共和水温观测资料出现显著异常变化,震中距280 km,两套仪器水温异常形态表现为2021年2月28日—3月3日出现同步上升-下降转折变化,幅度分别为0.047～0.075℃、0.007～0.240℃,截止3月21日,两套观测曲线同步转平,与以往震例类似,异常结束62天后,发生玛多地震。通过不同时段的水化组分对比分析,讨论其差异性,认为:(1)水化学类型为HCO_3-Na、HCO_3·SO_4-Na,水-岩反应程度较弱;(2)Na-K-Mg三角图显示,水样点分布在异常出现后,部分平衡水区域与正常时段及震后水样的分布域差异性大。结果表明,异常出现后由于区域应力调整,导致地层中深部热水在向地表上升的过程中流经岩石地层时受到中等矿化的部分平衡水混入,使水体矿化度及水化组分发生显著变化,带入更多深部元素补给,结合异常形态及历史震例研究分析,认为该异常是较为可信的地震前兆异常。     

广西平桂地区锡矿土壤离子电导率异常特征 和离子成分及找矿预测

为了解广西平桂地区锡矿土壤离子电导率异常特征,研究不同种类离子的含量变化关系对电导率的贡献大小,为解释锡矿土壤离子电导率异常的形成机制提供理论依据.对广西平桂地区锡矿的土壤离子电导率异常进行研究,结果表明:①在已知锡矿体上测出了清晰的土壤离子电导率异常,异常形态呈典型双峰形态“兔耳”状或“单峰”状,异常垂直指示锡矿体的赋存位置;②弄清了锡矿体组成土壤离子电导率异常的离子成分特征,其成分主要是SO42-、Ca2+、HCO3-、C1-、Fe3+、Mg2+、Na+、K+、Mn2+、F-等一套水可溶性离子,经过相关分析得出锡矿土壤离子电导率异常与各种水可溶性离子的相关系数SO42+＞Ca2+＞HCO3＞Cl＞Fe3+＞Mg2+＞Na+＞K+＞Mn2+F-;③在未知区的找矿预测中找到2个具有成矿远景的土壤离子电导率异常,经深部工程验证找到了隐伏锡矿体.     

New Approaches and Markers for Identifying Secondary Biogenic Coalbed Gas

According to the adsorption-desorption characteristics of coalbed gas and analysis of various experimental data, this paper proposes that the generation of secondary biogenic gas (SBG) and its mixing of with the residual thermogenic gas at an early stage inevitably lead to secondary changes of the thermogenic gas and various geochemical additive effects. Experimental results also show that the fractionation of the carbon isotope of methane of coal core desorption gas changes very little; the δ13C1 value of the mixed gas of biogenic and thermogenic gases is between the δ13C1 values of the two “original” gases, and the value is determined by the carbon isotopic compositions and mixing proportions of the two “original” methanes. Therefore this paper proposes that the study on the secondary changes of the thermogenic gas and various additive effects is a new effective way to study and identify SBG. Herein, a systematic example of research on the coalbed gas (Huainan coalbed gas) is further conducted, revealing a series of secondary changes and additive effects, the main characteristics and markers of which are: (1) the contents of CO2 and heavy-hydrocarbons decrease significantly; (2) the content of CH4 increases and the gas becomes drier; (3) the δ13C and δD values of methane decrease significantly and tend to have biogenetic characteristics; and (4) the values of δ13C2 and δ13CCO2 grow higher. These isotopic values also change with the degradation degrees by microbes and mixing proportions of the two kinds of gases in different locations. There exists a negative correlation between the δ13C1 vs δ13CCO2 values. The △δ13CC2–C1 values obviously become higher. The distributions of the △δ13CCO2–C1 values are within certain limits and show regularity. There exist a positive correlation between the N2 versus Ar contents, and a negative correlation between the N2 versus CH4 contents, indicating the down forward infiltration of the surface water containing air. These are important markers of the generation and existence of SBG.     

Field hyperspectral data analysis for discriminating spectral behavior of tea plantations under various management practices

The quality and yield of tea depends upon management of tea plantations, which takes into account the factors like type, age of plantation, growth stage, pruning status, light conditions, and disease incidence. Recognizing the importance of hyperspectral data in detecting minute spectral variations in vegetation, the present study was conducted to explore applicability of such data in evaluating these factors. Also stepwise discriminant analysis and principal component analysis were conducted to identify the appropriate bands for accessing the above mentioned factors. The Green region followed by NIR region was found as most appropriate best band for discriminating different types of tea plants, and the tea in sunlit and shade condition. For discriminating age of plantation, growth stage of tea, and diseased and healthy bush, Blue region was most appropriate. The Red and NIR regions were best bands to discriminate pruned and unpruned tea. The study concluded that field hyperspectral data can be efficiently used to know the plantation that need special care and may be an indicator of tea productivity. The spectral signature of these characteristics of tea plantations may also be used to classify the hyperspectral satellite data to derive these parameters at regional scale.     

The potential of spectral mixture analysis to improve the estimation accuracy of tropical forest biomass

A main limitation of pixel-based vegetation indices or reflectance values for estimating above-ground biomass is that they do not consider the mixed spectral components on the earth's surface covered by a pixel. In this research, we decomposed mixed reflectance in each pixel before developing models to achieve higher accuracy in above-ground biomass estimation. Spectral mixture analysis was applied to decompose the mixed spectral components of Landsat-7 ETM+ imagery into fractional images. Afterwards, regression models were developed by integrating training data and fraction images. The results showed that the spectral mixture analysis improved the accuracy of biomass estimation of Dipterocarp forests. When applied to the independent validation data set, the model based on the vegetation fraction reduced 5–16% the root mean square error compared to the models using a single band 4 or 5, multiple bands 4, 5, 7 and all non-thermal bands of Landsat ETM+.     

Technogenic hydrogeochemical anomalies of tungsten deposits in Kykylbey ore region

Peculiarities of the tungsten deposits drainage flow chemical composition formation, the development of which was ceased almost 40 years ago, have been considered. Migration peculiarities of ore components have been covered, and forms of their migration have been calculated. Inertial characteristics of the surface flow contamination are shown.     

Effect of watershed subdivision on simulation of water balance components

The present effect of watershed subdivision on simulated water balance components using the thoroughly tested Soil and Water Assessment Tool (SWAT) model has been evaluated for the Nagwan watershed in eastern India. Observed meteorological and hydrological data (daily rainfall, temperature, relative humidity and runoff) for the years 1995 to 1998 were collected and used. The watershed and sub‐watershed boundaries, slope and soil texture maps were generated using a geographical information system. A supervised classification method was used for land‐use/cover classification from satellite imagery of 1996. In order to study the effect of watershed subdivision, the watershed was spatially defined into three decomposition schemes, namely a single watershed, and 12 and 22 sub‐watersheds. The simulation using the SWAT model was done for a period of 4 years (1995 to 1998). Results of the study showed a perfect water balance for the Nagwan watershed under all of the decomposition schemes. Results also revealed that the number and size of sub‐watersheds do not appreciably affect surface runoff. Except for runoff, there was a marked variation in the individual components of the water balance under the three decomposition schemes. Though the runoff component of the water balance showed negligible variation among the three cases, variations were noticed in the other components: evapotranspiration (5 to 48%), percolation (2 to 26%) and soil water content (0·30 to 22%). Thus, based on this study, it is concluded that watershed subdivision has a significant effect on the water balance components. Copyright © 2005 John Wiley & Sons, Ltd.     

X射线荧光光谱法同时测定石灰石中主次痕量组分

采用熔融玻璃片和粉末压片法制样,选用标准样品,以经验α系数和散射线内标法校正元素谱线重叠干扰和基体效应,用ZSX PrimusⅡX射线荧光光谱仪对石灰石样品中CaO、Na2O、MgO、Al2O3、SiO2、K2O、TFe2O3、P2O5、TiO2、MnO和S等主次痕量组分进行测定,分析结果与标准值和化学值相符,12次测定的相对标准偏差小于10%。