一种基于回归分析与时序分析的降水预报模型

中长期降水预报存在的问题是资料不足和预报精度较低.运用回归分析与时序分析相结合的方法,将实测降水序列分解成趋势、周期、随机3种成分,并分别构建各分量的子模型;将3个子模型线性叠加,并对拟合的纯随机序列进行修正,得到降水预报的第三类模型;进而给出了模型精度评价方法.实例分析表明,运用修正后的模型进行降水预报,可以缩小峰值处的误差,预报精度比其余两类模型有所提高.该方法可仅根据历史资料进行降水预报,对资料要求较低,精度可靠,是一种实用的方法.     

基于马尔柯夫过程和概率分布特征的粮食产量预测

通过分析粮食单产中气象产量分量时间序列的变化规律，综合运用马尔柯夫模型和概率密度分布函数，构建相对气象产量预测模型。以河南省民权县和陕西省武功县1949—1999年小麦单产序列为例构建模型，预测得到2000年两地区小麦产量的相对误差在20％以下。预测结果表明：综合运用马尔柯夫过程和概率分布特征预测粮食产量的方法是有效的。     

基于Box—Jenkins方法的黄河水质时间序列分析与预测

采用基于Box-Jenkins方法的时间序列分析技术,对黄河上游甘肃兰州段、中游吴堡和下游山东利津段的水质进行了趋势分析和预测。选取对水质产生影响较大的两个污染因子化学需氧量（CODMn）和溶解氧（D0O1994—2003连续10a的月平均水质监测数据,借助Matlab和SAS统计软件,建立了ARIMA模型和乘积季节时间序列模型,并分析了这两个污染因子随时间推移的变化规律。结果表明：ARIMA模型和乘积季节模型能够用于短期水质预测,并且预测效果较好。黄河流域从上游到下游水质总体状况呈逐渐下降趋势,上游水质一般为Ⅱ和Ⅲ类,而中游和下游水质基本为Ⅳ、Ⅴ和超Ⅴ类。     

Multivariate Statistical Techniques for the Assessment of Surface Water Quality at the Mid-Black Sea Coast of Turkey

The aim of this study was to investigate the seasonal and spatial variations in surface water quality at the mid-Black Sea coast of Turkey. The samples were collected from ten monitoring stations including rivers and sea water during the years from 2007 to 2008. The samples were analyzed for 25 parameters: total carbon, total inorganic carbon, total organic carbon, chromium, cadmium, copper, lead, iron, nickel, manganese, phenol, surfactants, ammonium, nitrite and nitrate-nitrogen, total phosphorus, adsorbable organic halogen, sulfate, hardness, dissolved oxygen, pH, temperature, total dissolved solids, electrical conductivity, and salinity. Multivariate statistical techniques, cluster analysis (CA) and factor analysis/principal component analysis (FA/PCA), were applied to analyze the similarities among the sampling sites to identify the source apportionment of pollution parameters in surface waters. The results indicate that seven factors for river water explained 82.24% of the variance. In seawater, seven factors account for 89.65% of the total variance. Varifactors obtained from factor analysis indicate that the parameters responsible for water quality variations are mainly related to organic pollution (municipal effluents), inorganic pollution (industrial effluents and waste disposal areas), nutrients (agricultural runoff), and dissolved salts (soil leaching and runoff process).     

Mann-Kendall检验及其在河流悬沙浓度时间序列分析中的运用

探计了Mann-Kendall非参数秩次相关检验在时间序列分析方面的应用,并以云南省文山州盘龙河为例,把它运用到河流悬沙浓度时间序列的趋势分析和突变分析研究中.结果表明:①M-K检验同样适用于河流悬沙浓度的趋势与突变分析;②盘龙河自20世纪60年代初至90年代末河流悬沙浓度一直表现为波动上升趋势,1999年后有下降的迹象;③盘龙河的河流悬沙浓度自20世纪60年代以来存在着两个明显的突变点,其一在1973年,其二在1999年.     

霜冻灰色马尔柯夫链预测模型及其应用

用灰色马尔科夫预测方法，对石河子初霜冻出现时间进行了分析预测，结果表明，１９９５年预测初霜冻出现在１０月１８日，与实况１０月１８日完全一致。     

1961-2007年鄱阳湖周边地区气温变化趋势分析

基于鄱阳湖周边10个气象观测站的日平均气温、日最高气温和日最低气温的观测资料,利用Mann-Ken-dall(M-K)趋势分析法和Pettitt-Mann-Whitney突变点检验法,分析了1961-2007年鄱阳湖周边地区气温序列的变化特征。结果表明:(1)鄱阳湖周边地区日平均气温、日最高气温和日最低气温的年均值呈上升趋势,日最低气温的年均值增温幅度最大(0.25℃/10a)且显著性水平高,日平均气温的年均值次之,日最高气温的年均值增温趋势显著性较低;(2)日平均气温和日最低气温的冬季均温不仅突变时间开始早、显著性水平高,而且增温幅度也是最大的,春季均温、秋季均温次之,而夏季均温变化均不显著;(3)对比分析发现(1971-2004年),鄱阳湖周边地区增温趋势与全国及全球一致,但升温幅度(0.33℃/10a)高于全国的升温幅度(0.21℃/10a),也明显高于同期全球平均的升温幅度(0.15℃/10a)。     

流域泥沙模型中雨量资料的时空尺度分析

以经改进的格林－安普特下渗模型为基础,选择降雨资料有足够短的时段记载的流域和有足够密度雨量站的流域,分别变化时段长和站网密度计算产品,根据模型模拟精度与时段长及站网密度关系线的转折点,确定适当的时段长和合理的站网密度,通过曹坪流域的站网分析和６个小流域试验站的时段分析,发现对社些流域而言,时段长小于１５ｍｉｎ,站网密度大于２个／１００ｋｍ＾２,其降雨时空均化给模型计算带来的误差可以忽略。     

A Model Analysis of Transport of Sulfur Oxides in China and Outflow to the Sea

A numerical analysis of modeled long-range transport of sulfur oxides in the continental areas of East Asia with some verification was introduced. Although several modeling studies on acidic deposition in East Asia have been done, only few cases have verified in wide areas. In this study, the model calculation has been compared with the monthly averaged sulfur concentration in precipitation observed at 69 locations widely covering China from July 1992 through January 1993. Additionally, the atmosphericSO₂ ⁹⁰Sr concentration along the east coast of the continent was also compared with the observation in May 1993, and found to be reasonably consistent. Basing on these comparisons, the budget of sulfur oxides in China, especially about the outflow from the east coast to the sea areas was examined considering the seasonal variation of distribution of wet deposition and the pathways of atmospheric sulfur oxides. The seasonal variation of these indices was found to have large difference between the north and the south of 35°N. The outflow from the east coast increased remarkably in winter due to the decrease of deposition in the inland areas along the transport pathways.     

Model Simulations of the Alkaline Dust Distribution from Estonian Sources over the Baltic Sea Basin

The model calculations of oil-shale fly ash deposition from the Narvapower plants (north-eastern Estonia) are performed using the models HILATAR (regional scale) and AEROPOL (local scale). The modelling results are compared with air quality monitoring results from the observation stations in the Baltic Sea region and with the results of snow pollution study in Estonia. It was found, that although the bulk of the ash emitted is deposited near the sources, the emissions are large enough to create remarkable background deposition in the Baltic Sea region. The uncertainties related to the effective particle size are discussed and corresponding sensitivity studies are performed.     

高光谱土壤多元信息提取模型综述

  目的  以长沙及周边区域水田土壤为研究对象,从特征空间和样本空间角度优化建模数据集,以提升基于土壤高光谱数据估测有机质含量模型的精度。  方法  利用马氏距离(MD)优化土壤光谱特征空间、最小生成树(MST)分割样本数据集优化建模样本空间,结合交叉验证岭回归(RidgeCV)和支持向量机回归(SVR)构建土壤高光谱有机质含量估测模型。  结果  在测试集上,光谱优化建模方法MD-RidgeCV和MD-SVR的模型决定系数(R²)分别为0.876、和0.84,样本优化建模方法MST-RidgeCV和MST-SVR 的R²指标分别为0.847和0.815,而两种优化方法相结合的MD-MST-RidgeCV和MST-MD-RidgeCV模型 R²指标均高达0.9;对比基于原始数据集和建模集优化KS和SPXY方法的土壤有机质含量估测模型,提出的方法在测试集上具有更佳的模型预测性能。  结论  利用马氏距离和最小生成树,从光谱特征空间和样本空间优化建模数据集,并结合回归算法RidgeCV和 SVR构建土壤有机质含量高光谱预测模型,能显著提高模型精度和稳定性。     

A Simple Feedforward Neural Network for the PM10 Forecasting: Comparison with a Radial Basis Function Network and a Multivariate Linear Regression Model

Water, Air, & Soil Pollution - The problem of air pollution is a frequently recurring situation and its management has social and economic considerable effects. Given the interaction of the...     

Ecological Risk Assessment of Riverine Contamination in the Caspian Sea Basin: A Conceptual Model for Persistent Organochlorinated Compounds

A conceptual model of the ecological risk assessment for persistent organochlorinated compounds (POCs), like DDT, HCH, and PCBs, which contaminate reservoirs and river waters entering into the Caspian Sea is presented. The model can be used to evaluate the toxicity of POCs in these environments. Examples of this model application using POCs monitoring data for water and bottom sediments of different reservoirs and rivers of the Caspian Sea basin are presented.     

基于生理发育时间的日光温室番茄发育模拟模型

掌握温室番茄生育期是温室番茄专家决策系统中进行生产安排和市场销售的重要内容，本研究将温度对番茄发育速率影响效应的大小用相对热效应（RTE）来衡量，通过研究Beta函数的性质提出基于幂函数的模型来描述RTE与温度之间的关系。每日相对热效应（RTE）决定每日生理发育效应（PDE）的大小，其累积形成每日的生理发育时间。采用生理发育时间（PhysiologicalDevelopmentTime，PDT）作为定量发育进程的尺度，建立了温室番茄发育模拟模型。利用模型对日光温室2年4茬番茄生长发育期资料进行检验的结果表明：模型能较好地预测各个发育期（发芽、苗期、开花座果、结果和采收期）的出现时间和持续时间，各生育期模拟值与观测值的回归估计标准误差（RMSE）分别为1．32d，1．73d，0．35d，1．58d，2．52d，显著优于以有效积温模拟模型的预测精度（其生育期模拟的RMSE分别为2．55d，9．74d，2．06d，9．27d，11．99d）。     

基于马尔柯夫模型的红壤退化地水土流失动态变化预测研究

文章阐述了马尔柯夫模型在水土流失动态变化预测中的应用,并选取福建省长汀县为研究区,分别利用长汀县2000年和2007年的遥感影像图,在RS软件和GIS软件支持下,运用马尔柯夫模型预测了2014年该县的水土流失变化情况.研究发现:在2007-2014年,长汀县的水土流失趋势是流失面积和强度在一定程度上得到控制,总的水七流失面积缩小,强度降低,极强度和剧烈侵蚀不明显,生态环境得到好转.这一发现说明红壤退化地的水土流失丁F处在一种变化状态,预示着未来时期以长汀县为代表的红壤退化地人为干扰仍然是水土流失面积和强度变化的上要方面,红壤退化地的水土保持任务仍较艰巨.     

基于Markov模型的长沙市和泉州市土地利用变化预测及对比研究

为探索中国中部地区和东部沿海地区典型代表城市的土地利用程度变化特征和未来演变趋势,采用地理比较分析方法,基于地理信息技术（GIS）、遥感技术和Markov模型对长沙市和泉州市未来土地利用进行模拟预测,结合土地利用程度指数分析1990—2020年期间土地利用的变化情况及其变化趋势异同,试揭示不同时期、不同区域内土地利用程度变化差异性。研究结果表明:1995—2020年期间,长沙市数量结构变化较泉州市更为稳定,耕地和建设用地所占比例结构变化具有较大差异性;土地利用程度指数的对比研究表明,两市综合程度指数均呈现一定增长,且泉州市土地利用综合程度指数变化趋势较长沙市更为显著,其土地利用程度变化量和变化率均大于长沙市。研究结果可为两市区域土地利用规划提供参考,并将有利于我国东南沿海和中部城市土地利用的可持续发展和生态环境保护。     

A Model for Evaluating the Feasibility of an Extraction Procedure for Heavy Metal Removal from Contaminated Soils

A model was developed that allowed for the evaluation of a soil metal cleaning technique in a rapid and cost effective manner. Metal flow (Pb, Cu, Zn, and Cd) during a counter-current soil-acid extraction procedure, consisting of a decarbonation, solubilisation, and washing step, was determined. Required input data are total soil metal content and metal equilibrium distribution coefficients, derived from batch equilibration experiments. The model was calibrated and validated against experimentally obtained results. Model predictions adequately described metal behaviour and removal in each of the extraction steps. Based on the results, optimum operating conditions for the steps involved in the extraction procedure were determined and the feasibility of the counter-current extraction procedure for heavy metal removal from a contaminated soil evaluated.     

Multivariate Statistical and GIS-Based Approach for the Identification of Mn and Ni Concentrations and Spatial Variability in Soils of a Humid Mediterranean Environment: La Rioja, Spain

Limnologists have regarded temporal coherence (synchrony) as a powerful tool for identifying the relative importance of local-scale regulators and regional climatic drivers on lake ecosystems. Limnological studies on Asian reservoirs have emphasized that climate and hydrology under the influences of monsoon are dominant factors regulating seasonal patterns of lake trophic status; yet, little is known of synchrony or asynchrony of trophic status in the single reservoir ecosystem. Based on monthly monitoring data of chlorophyll a, transparency, nutrients, and nonvolatile suspended solids (NVSS) during 1-year period, the present study evaluated temporal coherence to test whether local-scale regulators disturb the seasonal dynamics of trophic state indices (TSI) in a giant dendritic reservoir, China (Three Gorges Reservoir, TGR). Reservoir-wide coherences for TSI_CHL, TSI_SD, and TSI_TP showed dramatic variations over spatial scale, indicating temporal asynchrony of trophic status. Following the concept of TSI differences, algal productivity in the mainstream of TGR and Xiangxi Bay except the upstream of the bay were always limited by nonalgal turbidity (TSI_CHL?TSI_SD <0) rather than nitrogen and phosphorus (TSI_CHL?TSI_TN <0 and TSI_CHL?TSI_TP <0). The coherence analysis for TSI differences showed that local processes of Xiangxi Bay were the main responsible for local asynchrony of nonalgal turbidity limitation levels. Regression analysis further proved that local temporal asynchrony for TSI_SD and nonalgal turbidity limitation levels were regulated by local dynamics of NVSS, rather than geographical distance. The implications of the present study are to emphasize that the results of trophic status obtained from a single environment (reservoir mainstream) cannot be extrapolated to other environments (tributary bay) in a way that would allow its use as a sentinel site.     

土壤侵蚀模拟的高维指数非线性模型及参数辨识方法研究

针对常规土壤侵蚀经验统计模型适用性不强、模拟精度不佳等问题,对灰色离散序列高阶动态模型进行合理扩展,建立了多变量高维指数非线性模型,通过MATLAB寻优,实现了非线性模型中参数的搜索--辨识.该模型具有信息包容量丰富、信息开发利用潜力大、适用范围广等特点.人工降雨条件下的坡耕地土壤侵蚀模拟结果表明:模型有效系数>0.91.平均误差率<6.2%,模拟精度较高.     

基于代表性植株二次选择和多元统计分析的芦笋芽期苗期耐盐性鉴定及综合评价

土壤盐渍化是制约农业发展的逆境因素之一,筛选耐盐种质可为芦笋耐盐新品种选育和耐盐机理研究奠定基础。本研究以49个芦笋品种为试验材料,采用二次选择法选择代表性植株,设0 mmol·L^-1NaCl(CK)和310 mmol·L^-1NaCl(T)2个水培处理,分别测定发芽率、发芽势等4个芽期指标和株高、根长等8个苗期指标,以耐盐系数为基础,运用多元统计分析方法进行耐盐性综合评价。结果表明,盐胁迫极显著影响各项指标(P<0.01),其中,地下部干重和根冠比耐盐系数大于1,其余指标耐盐系数均小于1。相关性分析表明,芽期各指标间均存在极显著相关性(P<0.01),苗期大部分指标间存在显著(P<0.05)或极显著(P<0.01)相关性。芽期基于U值聚类将供试品种划分为强耐盐、中耐盐、弱耐盐和盐敏感4个耐盐级别;苗期通过主成分分析将8个单项指标转换为3个综合指标,反映了全部信息的77.805%,基于D值聚类鉴定出苗期强耐盐品种12个、中耐盐品种20个、弱耐盐品种14个、盐敏感品种3个,其中,冠军和特立龙在芽期和苗期均表现为强耐盐。芽期基于U值和苗期基于D值的耐盐性排序与同时期综合耐盐系数(CSC)和加权耐盐系数(WSC)基本一致。本研究方法较传统鉴定方法更为科学、合理,可大幅减少田间全生育期鉴定工作量,适用于大规模芦笋种质耐盐性评价,对盐渍化土壤的改良利用具有重要意义。