Component flow processes at four streams in the Catskill Mountains,New York,analysed using episodic concentration/discharge relationships

Plots of solute concentration against discharge have been used to relate stream hydrochemical variations to processes of flow generation, using data collected at four streams in the Catskill Mountains, New York, during the Episodic Response Project of the US Environmental Protection Agency. Results suggest that a two‐component system of shallow and deep saturated subsurface flow, in which the two components respond simultaneously during hydrologic events, may be applicable to the study basins. Using a large natural sea‐salt sodium input as a tracer for precipitation, it is argued that an additional distinction can be made between pre‐event and event water travelling along the shallow subsurface flow path. Pre‐event water is thought to be displaced by infiltrating event water, which becomes dominant on the falling limb of the hydrograph. Where, as appears to be the case for sulfate, a solute equilibrates rapidly within the soil, the pre‐event–event water distinction is unimportant. However, for some solutes there are clear and consistent compositional differences between water from the two sources, evident as a hysteresis loop in concentration–discharge plots. Nitrate and acidity, in particular, appear to be elevated in event water following percolation through the organic horizon. Consequently, the most acidic, high nitrate conditions during an episode generally occur after peak discharge. A simple conceptual model of episode runoff generation is presented on the basis of these results. Copyright © 1999 John Wiley & Sons, Ltd.     

大兴安岭东北部永新金矿床金银系列矿物和碲化物的发现及其意义

永新金矿床是早白垩世晚期形成的浅成低温热液型金矿床。对其主要金银系列矿物和碲化物研究显示:金银系列矿物中Au质量分数为65.092%~90.713%(平均为83.942%),Ag为5.652%~16.632%(平均为11.285%);以自然金和银金矿为主,成色集中在870.2~941.3(平均为881.1),主要以包体金、粒间金和裂隙金的形式存在,粒径集中在10~20 μm;碲化物主要有辉碲铋矿、碲金银矿、碲银矿和碲铅矿等,以碲银矿数量最多,主要包裹于黄铁矿内部或产于裂隙中,常与自然金和方铅矿连生,粒径多为5~20 μm。综合研究碲化物组合特征、不同标高金矿物的成色、Te/Au值等认为,永新金矿床碲化物形成时成矿流体的lgf(Te₂)介于-15.2~-9.4范围,lgf(S₂)介于-16.7~-14.0范围,矿床与火山或次火山热液有关,具备中浅成成矿特征,深部尚有较大成矿潜力。     

总体最小二乘回归预测模型的方差分量估计

回归预测模型是对传统回归模型的进一步扩展,不仅涉及回归模型的固定参数估计,而且将模型预测纳入平差的部分内容,更加符合实际解算需求.针对在回归模型预测中经常出现待预测非公共点(自变量)含有观测误差和随机模型不准确的问题,基于EIV (errors-in-variables)模型提出了一种同时顾及所有变量观测误差的整体解法...     

加权整体最小二乘的验后估计在三维坐标转换中的应用

在求解三维小角度坐标转换EIV模型的过程中,顾及到两套坐标系下点坐标初始单位权方差可能不同导致定权不准确的问题,应用Helmert方差分量估计方法,对加权整体最小二乘的随机模型进行验后估计,从而重新分配观测向量和系数矩阵的权,使得解算模型更加合理。算例证明,利用该方法求解坐标转换参数的精确度有所提高,参数估值更接近真值。     

台湾周遭之地下水入海

A preliminary study shows that the submarine groundwater discharge(SGD) exists around Taiwan even though groundwater overdrawing on the island is serious. Fifteen of the 20 sites studied for major anions and cations recorded a clear SGD signal with freshwater outflow. A total of 278 salinity and major ion measurements were made. Sixteen nearly freshwater SGD(salinity≤1.0) samples were obtained, providing strong and direct evidence for the existence of fresh meteoric groundwater entering the ocean from Taiwan. The total SGD flux is estimated to be 1.07×1010 t/a which is about 14% of the annual river output. The freshwater component of the SGD is3.85×109 t which is about 5.2% of the annual river discharge in Taiwan. The collected SGD has a composition similar to seawater with an addition of Ca, CO_3 and HCO_3 due to dissolution of calcareous rocks. Some samples with high Cl/(Na+K) may indicate pollution.     

Deciphering Groundwater Flow Systems in Oasis Valley, Nevada, Using Trace Element Chemistry, Multivariate Statistics, and Geographical Information System

The origin of groundwater discharging via evapotranspiration and from springs within Oasis Valley, Nevada, is of concern owing to the close proximity of the Nevada Test Site (NTS) and the possible contamination of groundwater as a result of underground nuclear testing. Principal components analysis, cluster analysis, and population partitioning, along with a Geographical Information System, were used to decipher groundwater flow patterns in Oasis Valley, Nevada. These multivariate statistical techniques were applied to the trace element chemistry of groundwater samples collected from 26 springs and wells within Oasis Valley, the NTS, and the Nellis Air Force Range. The results of all statistical analyses showed similar geographical trends in the trace element chemistry of the groundwaters included in this study. Differences are observed between the groundwaters from the NTS and those of Oasis Valley based on the concentrations of the elements Li, Ge, Mo, Rb, Ba, U, and Ru. A concentration gradient is observed from lower concentrations in the NTS to increasing concentrations toward Oasis Valley suggesting groundwater flow in an overall southwestward direction from the NTS. Also, a different trace element signature is observed for the waters collected in the northern and western region of Oasis Valley, suggesting another source of groundwater to this area.     

一种基于Helmert方差分量估计的岭参数确定方法

为了使岭参数具有一个明确的含义,提出了一种基于Helm ert方差分量估计的岭参数确定方法。该方法把约束条件作为一类参数之间互相独立的虚拟观测,从而把岭参数转变为两类观测值的权比,然后用Helm ert方差分量估计的方法确定岭参数。通过算例,比较了该方法与岭迹法、L曲线法的效果。结果表明,该方法不仅计算过程简单、直接,而且精度也优于其他几种方法。     

Analysis and partitioning of terrestrial water storage in the Yellow River source region

In order to increase the capability to understand and quantify the spatial differences in terrestrial water storage (TWS), and to reflect the unique energy balance processes and soil freeze–thaw mechanisms in the Qinghai-Tibet Plateau (QTP), this study improved the energy balance processes of the water and energy transfer processes model, including its surface radiation calculations and snowmelt module. By integrating these improvements, a water and energy transfer processes model in Qinghai-Tibet Plateau (WEP-QTP) for the Yellow River source region (YRSR) is developed. Using the improved WEP-QTP model to perform simulations, we assessed the daily changes in snow cover, soil moisture (SM), permafrost (PM), and groundwater storage (GWS) in the YRSR. Our analysis revealed an increase in TWS of 0.24 mm/yr from 1961 to 2020. Snow water equivalent (SWE), SM, PM, and GWS have proportional contributions of 8.33%, 216.67%, −154.17%, and 29.17% to the increased TWS, respectively. SM is the primary component of TWS. Temperature (T), precipitation (P), evapotranspiration (E), and solar radiation (Rs) influence the spatiotemporal variations in TWS, as well as those of its components. The increase in P is the primary cause for the rise in TWS, SWE, and SM, while the increase in T predominantly contributes to the decrease in PM. Furthermore, permafrost degradation and climate-induced warming and humidification lead to increased infiltration, resulting in elevated GWS.     

HEIFE非均匀陆面上区域能量平衡研究

卫星遥感在研究非均匀陆面上地－气间能量和水循环过程时有其独到的作用。本文介绍了一种利用陆地资源卫星ＴＭ资料进行非均匀陆面上区域能量平衡研究的参数化方案。以两个景的ＴＭ资料（１９９１年７月９日,夏季;１９９１年１０月２９日,近冬季）为个例,结合“黑河实验”（ＨＥＩＦＥ）期间的地面观测资料分析研究了实验区非均匀陆面上地表特征参数（地表反射率、标准化差值植被指数和地表温度）及能量平衡各分量（地表净辐射通量、土壤热通量、感热和潜热通量）的区域分布及季节差异,同时将所得的结果与地面观测的“真值”作了比较。结果表明：（１）由于黑河实验区下垫面状况十分复杂,戈壁、沙漠与绿洲交错分布,故在整个实验区内各地表特征参数及能量平衡各分量的分布范围亦比较宽;（２）地表特征参数及能量平衡各分量在实验区的绿洲、戈壁及沙漠上各有其特定的代表值;（３）地表能量平衡各分量的区域平均值在整个实验区内基本平衡;（４）夏季与近冬季的地表特征参数及能量平衡各分量的分布特征存在着显著差异。所得的这些结果与地面观测的“真值”和局地研究的结论基本一致。这些分析对非均匀下垫面中尺度模式陆面过程参数化方案的建立以及模式预报效果的检验都具有不可缺少的重要意义。     

An individual-component approximation to quadratic stress for flow-decomposition analysis

An individual-component approximation (ICA) to the one-dimensional quadratic stress is presented for analysis of hydrodynamic systems that contain multiple-frequency fluid motion such as tidal current and nearshore currents. Criteria governing development of the approximation are accuracy, symmetry, and preservation of contributions (magnitude and direction) of individual and coupled velocity components. Preservation of directionality is required to isolate functioning of individual terms for flow-decomposition analysis. The ICA is compared with the small-amplitude approximation analytically and through numerical examination for two velocity components. The two approximations differ at second order within the range of validity of the small-amplitude approximation. The ICA is exact in the limits of components with large magnitudes and components of equal magnitudes. Based on calculations comparing the exact numerical solution for velocity components with a wide range of relative magnitudes, relative periods, and phase differences, the ICA is accurate except in restricted regions of small-magnitude quadratic velocity. The ICA is generalized to multiple components without restriction on magnitude, period, or phase, and example calculations are given for flows comprised of three components and six components. The method is applied to velocity tidal constituents for Galveston Bay, Texas, and Tampa Bay, Florida.