PARAMETER ESTIMATION IN HYDROLOGY: THE STATE OF THE ART1

ABSTRACT A detailed review of current methods and criteria used in parameter estimation in hydrology is presented. The effect of errors in the data set and the effect of interactions between methods of analysis, criteria, data set errors, and modeling assumptions are reviewed and discussed briefly. It is concluded that study of techniques, criteria, data set errors and particularly interactions between these, is essential to further progress in hydrologic modeling.     

FOURIER INFERENCE: SOME METHODS FOR THE ANALYSIS OF ARRAY AND NONGAUSSIAN SERIES DATA1

Fourier inference is a collection of analytic techniques and philosophic attitudes, for the analysis of data, wherein essential use is made of empirical Fourier transforms. This paper sets down some basic results concerning the finite Fourier transforms of stationary process data and then, to illustrate the approach, uses those results to develop procedures for: 1) estimating cloud and storm motion, 2) passive sonar and 3) fitting finite parameter models to nonGaussian time series via bispectral fitting. This last procedure is illustrated by an analysis of a stretch of Mississippi River runoff data. Examples 1), 2) refer to data having the form Y(x_j, y_j, t) for j = 1, …, J and t = 0, …, T-l say, and view that data as part of a realization of a spatial-temporal process. Such data has become common in geophysics generally and in hydrology particularly. The goal of this paper is to present some new statistical procedures pertinent to problems in the water sciences, equally it is to illustrate the genesis of those procedures and how their properties may be approximated.     

A STATISTICAL APPROACH TO ASSESS FACTORS AFFECTING WATER CHEMISTRY USING MONITORING DATA1

ABSTRACT: A method to partition the variation in concentrations of water chemistry parameters in a river is described. The approach consists of fitting a family of curves for each chemical parameter. Each curve indicates the response of the parameter to river flow for a particular time period or location. An analysis of covariance is then used to identify statistically significant differences between curves. Such differences result largely from two factors: (1) the discharge of effluents and (2) river flow-concentration relationships. The deviations from the fitted curves indicate month-to-month variations unrelated to river flow that are controlled by factors such as temperature-related seasonal patterns. Underlying statistical assumptions are discussed with respect to water chemistry data. The technique is applied to a data set consisting of monthly samples of 22 water chemistry parameters from the Sulphur River of Texas and Arkansas. Several patterns of response to river flow and to two effluent discharges were revealed.     

中等变质程度软硬煤瓦斯放散规律研究

自主设计了煤粒瓦斯吸附-放散试验系统,以郑煤集团告成煤矿普遍存在的中等变质程度贫瘦软硬煤为研究对象,对比分析了贫瘦煤软硬煤前120 min瓦斯解吸规律,试验结果表明,瓦斯解吸初期软煤的解吸速度都大于硬煤的解吸速度,软煤在前30 min解吸量占总解吸累积量的84.07%以上,而硬煤仅为67.76%;对比了多种描述瓦斯解吸-扩散过程的经验公式,发现孙重旭式和文特式拟合效果最好,且相关指数的变化范围较小。     

深圳市新一代暴雨强度公式的研制

首先构造了深圳市新一代暴雨强度公式研制的路线图，重点是利用深圳市气象局1954-2003年50年间的暴雨记录，用指数分布和P-Ⅲ分布进行分布曲线拟合和选优，得到了理论上的雨强-历时-重现期三联表，在此基础上再分别采用最优法、二分搜索法和广义逆法等3种方法求解分公式和总公式参数，根据误差最小的原则确定最优方法。结果表明：由指数分布拟合分布曲线，经过上述步骤求解得到的公式参数，误差最小，符合相关国标要求。     

臭氧综合指数与臭氧潜势指数的构建与应用

随着社会经济的快速发展,我国臭氧污染日益严重,因此,研发出能定量评估气象条件对臭氧污染影响程度的诊断指数,成为提高和改善气象服务质量的重要任务之一。利用中国大陆地区2018年温度、总云量、风速、风向、相对湿度等气象场数据与臭氧浓度数据,研究臭氧污染敏感气象条件,统计各气象因子分布在不同数值区间时发生臭氧污染事件的相对频率(即分指数),按照分指数最大值和最小值的差值大小进行排序,筛选出10个与臭氧污染密切相关的气象因子,将10个气象因子的分指数进行累加,即得出臭氧综合指数。随后,对各地构建臭氧综合指数时采用的气象要素进行统计,得到出现频率最高的3个气象要素,并参考这些气象要素构建了臭氧潜势指数。分别以臭氧潜势指数和臭氧综合指数对北京市2019年臭氧日最大浓度建立拟合预报模型,结果表明:两类指数的拟合预报值与实测值有着相似的变化趋势;利用臭氧综合指数计算得到的预报值与实测值的相关系数为0.76,优于利用臭氧潜势指数计算得到的预报值与实测值的相关系数(0.64)。     

旅游资源竞争力与旅游收入关系实证分析——以安徽省17地市为例

在构建旅游资源竞争力评价指标体系的基础上,运用位序得分法对安徽省17个地市的旅游资源竞争力进行了评价,同时借助两轴折线图、散点图及拟合曲线等工具对17个地市旅游资源竞争力与旅游收入关系进行了实证分析。结果表明,安徽省绝大多数地市旅游业发展仍依赖于旅游资源;少数地市旅游资源竞争力与旅游收入出现偏离,成为非旅游资源依赖性城市。从资源属性来看,综合类旅游资源与旅游收入的相关性最大,其次为自然类旅游资源,人文类的相关性最小。     

甲苯气体的动态吸附净化及吸附剂再生实验研究

研究了活性炭纤维(ACF)对甲苯气体的动态吸附净化过程及热空气解吸脱附再生过程.采用3种经验方程对ACF的吸附等温线进行拟合,其中Langmuir方程拟合效果最好,拟合相关系数R2 =0.9960,说明在给定的浓度范围内,ACF对甲苯的吸附是以单分子层吸附为主.穿透曲线实验表明,ACF对甲苯吸附效果较好,Yoon-Ne...     

聚乙烯残膜破碎过程对土壤水分入渗的影响

为探究残膜-微塑料破碎过程对土壤水分入渗能力的影响,通过室内土柱试验,设置5组残膜-微塑料比例（100%～0,75%～25%,50%～50%,25%～75%,0～100%）来模拟不同的残膜破碎程度,研究了残膜-微塑料破碎对湿润锋运移和累积入渗量的影响,并评价了主要入渗模型在不同破碎程度土壤中的适用性.结果表明,湿润锋运移速率和累积入渗量随着残膜-微塑料破碎程度的增大而增大,当入渗时间为300min时,残膜完全破碎组（T4）较未破碎组（CK）的湿润锋运移距离增大48.72%（P<0.05）,累积入渗量增大46.77%.随着残膜破碎程度的增大,各模型拟合效率呈现上升的趋势.湿润锋推进模型的参数B随着残膜破碎程度的增大呈现增大的趋势.Kostiakov模型的参数α,Philip模型中的参数S和C随残膜破碎程度增大而增大.总体上,Kostiakov模型对土壤累计入渗量的模拟效果优于Philip模型.本研究可为残膜污染土壤的水分入渗规律和模拟研究提供参考.     

亚青会期间南京地区气溶胶浓度变化及其与能见度的关系

为保障2014年青奥会空气质量和制定控制措施提供科学支持,利用2013年8月南京市气溶胶的观测资料,结合气象要素,分析了南京地区气溶胶浓度变化特征,并深入研究了气溶胶质量浓度与相对湿度对能见度的影响.结果表明,观测期间PM10和PM2.5质量浓度平均值分别为67.44μg·m-3和31.92μg·m-3,0.1~10μm粒径范围内的气溶胶粒子数浓度和体积浓度的平均值分别为2466.25 cm-3和19.89μm3·cm-3;对数正态分布(log-normal)拟合平均谱分布得到两个模态的中值粒径分别为0.19μm和1.12μm;局地源强是影响南京气溶胶浓度的重要因子;PM10和PM2.5质量浓度日变化略有差异,PM10浓度日变化主要受交通和边界层活动影响,PM2.5浓度日变化则主要受交通排放和光化学反应生成的二次污染物的影响;对能见度的统计分析表明,能见度随PM2.5浓度和相对湿度的增加而降低,当相对湿度小于70%时,PM2.5浓度对能见度的影响较大,当相对湿度大于70%时,相对湿度对能见度的影响较大.