酸化水体中的浮游生物及其与主要化学因子的关系

１９９１－１９９２年对重庆市郊若干酸化水体的生物待正与理化参数进行综合研究的结果表明，藻类的种类数、细胞密度、生物量和叶绿素ａ含量以及浮游动物的种类数等均与呈正相关，但与Ｈ＋和总Ａｌ浓度呈负相关。浮游动物的个体密度在酸化水体中明显下降，但是鱼的捕食作用掩盖了其与上述化学参数之间的相关性。水体中Ｈ＋和总Ａｌ浓度的增加在很大程度上对浮游生物产生了不利影响，水体的透明度、总Ａｌ．ＴＰ和ＳＯ与ｐＨ的相关性十分明显，ｒ值分别为－０．６３７５、－０．６８６８、０．７５６１和０．７３２３。     

Bandwidth determination for kernel density analysis of wildfire events at forest sub-district scale

Forest fire is regarded as one of the most significant factors leading to land degradation. While evaluating fire hazard or producing fire risk zone maps, quantitative analyses using historic fire data is often required, and during all these modeling and multi-criteria analysis processes, the fire event itself is taken as the dependent variable. However, there are two main problematic issues in analyzing historic fire data. The first difficulty arises from the fact that it is in point format, whereas a continuous surface is frequently needed for statistically analyzing the relationship of fire events with other factors, such as anthropogenic, topographic and climatic conditions. Another, and probably the most bothersome challenge is to overcome inaccuracy inherent in historic fire data in point format, since the exact coordinates of ignition points are mostly unknown. In this study, kernel density mapping, a widely used method for converting discrete point data into a continuous raster surface, was used to map the historic fire data in Mumcular Forest Sub-district in Mu?la, Turkey. The historic fire data was transferred onto the digital forest stand map of the study area, where the exact locations of ignition points are unknown; however, the exact number of ignition points in each compartment of the forest stand map is known. Different random distributions of ignition points were produced, and for each random distribution, kernel density maps were produced by applying two distinct kernel functions with several smoothing parameter options. The obtained maps were compared through correlation analysis in order to illustrate the effect of randomness, choice of kernel function and smoothing parameter. The proposed method gives a range of values rather than a single bandwidth value; however, it provides a more reliable way than comparing the maps with different bandwidths subjectively by eye.     

Generating Synthetic Rainfall on Various Timescales—Daily, Monthly and Yearly

The main objective of this paper is to present a model for generating synthetic rainfall totals on various timescales to be applicable for a variety of uses. Many large-scale ecological and water resource models require daily, monthly and yearly rainfall data as input to the model. As historical data provides only one realisation, synthetic generated rainfall totals are needed to assess the impact of rainfall variability on water resources systems (Srikanthan, In: MODSIM2005, Melbourne, Dec. 2005, pp. 1915–1921, 2005). Thus, our preferred model should simulate rainfall for yearly, monthly and daily periods. We believe that, for water supply issues, no higher resolution is needed, although higher resolution would be useful in models designed to measure the risk of local flooding. The critical factors are daily, monthly and yearly totals and daily, monthly and yearly variation. A model for generating yearly totals will be described using traditional time series methods. This model, along with a similarly constructed daily generation model by Piantadosi et al. (A New Model for Correlated Daily Rainfall, 2008), will be cascaded to start with a synthetic yearly total, then generate a synthetic sequence of monthly totals (through selection from a large number of realisations) that match the yearly total, and subsequently perform a similar operation for sequences of daily totals to match the required monthly totals. We present a new model for the generation of synthetic monthly rainfall data, which we demonstrate for Parafield in Adelaide, South Australia. The rainfall for each month of the year is modelled as a non-negative random variable from a mixed distribution with either a zero outcome or a strictly positive outcome. We use maximum likelihood to find parameters for both the probability of a zero outcome and the gamma distribution that best matches the observed probability density for the strictly positive outcomes. We describe a new model that generates correlated monthly rainfall totals using a diagonal band copula with a single parameter to generate lag-1 correlated random numbers. Our model preserves the marginal monthly distributions and, hence, also preserves the monthly and yearly means. We show that, for Parafield, the correlation between rainfall totals for successive months is not significant, and so, it is reasonable to assume independence. This is, however, not true for daily rainfall. We describe a new model that generates correlated daily rainfall totals using a diagonal band copula with a single parameter to generate lag-1 correlated random numbers. This is an extended version of a paper presented at the 17th Biennial Congress on Modelling and Simulation, Christchurch, New Zealand, December 2007.     

高层建筑人员竖向疏散途径选择特性调查研究

高层建筑人员竖向疏散途径选择与人的生理特征、文化背景、行为习惯等人员特征密切相关,因此开展针对我国高层建筑人员疏散途径选择特征的数据采集和分析工作十分重要。设计并开展了高层建筑竖向疏散途径选择的问卷调查。对人员在日常和紧急条件下高层建筑竖向疏散途径的选择进行了统计分析,分别针对距离因素、排队因素、群体因素影响的不同条件下人员选择电梯进行上下楼层的期望值进行了对比分析。利用Pearson相关性检验和多重对应分析方法,保障电梯疏散可行前提下,研究了人员性别、年龄、文化程度、职业、身型特征、生理和心理状态、日常行为习惯等人员特征因素和竖向疏散途径选择之间的相关关系。     

2013-2018年北京市PM2.5污染波动特征研究

利用2013—2018年北京市大气污染物监测数据及气象条件等资料,分析了北京市PM_(2.5)污染波动变化趋势及其影响因素。结果表明,2013—2018年北京市空气质量呈现整体改善趋势,优良天数由2013年的176 d增加至2018年的227d;重污染天数显著减少,由2013年的58 d逐年递减至2018年的14 d。受污染源排放、特殊气候现象、气象条件等多因素影响,近6年北京市ρ(PM_(2.5))月均值呈现波动下降趋势,其中秋、冬季波动性更加突显。2014—2016年北京市秋冬季PM_(2.5)污染突出,其中2014年10月、2015年11—12月、2016年12月ρ(PM_(2.5))月均值均达到中度污染级别;而2017—2018年北京市秋、冬季ρ(PM_(2.5))月均值均处于优良水平。相关性分析结果显示,地面相对湿度、中层温度与大气污染物呈现较强的正相关性,中层北风频率、地面风速则呈现负相关性。基于上述气象条件及CO、SO_2和NO_2等气态污染物共同构建的拟合方程对ρ(PM_(2.5))估算结果较好,多站点的拟合值与实际值的相关系数为0.900～0.947,进一步说明气象条件及相关污染源排放对PM_(2.5)污染具有显著影响。     

空气环境容量核定中提高年均值符合度和相关性的措施

提出了空气环境容量核定中扩散模型验证的有效指标,简述了满足指标应当采取的措施。     

Comparison of EC and BC and evaluation of dust aerosol contribution to light absorption in Xi'an, China

The concentrations of EC, BC and dust aerosols were determined for atmospheric samples collected from an observation station in Xi'an, China. The results show that the averaged correlation coefficient between EC and BC was founded to be 0.72 with 0.81 (n = 49) in autumn, 0.70 (n = 112) in winter and 0.69 (n = 57) in spring, respectively. Absorption coefficients of dust aerosol were estimated to be 2.7 m² g⁻¹ in autumn and 4.4 m² g⁻¹ in winter. The comparison of absorption coefficients of dust aerosol with those of BC implies that BC is the principal light-absorbing aerosol over Xi'an atmosphere. By combining thermal analysis of elemental carbon and dust contents in the aerosol samples, however, the fraction of dust absorption to total light absorption is estimated to be 19% in autumn and 31% in winter, respectively.     

我国能源结构-产业结构协调性演进规律研究

从我国目前实际发展现状来看,只有能源结构与产业结构协调发展、共同调整,才能实现经济增长和保障能源安全的目标。运用灰色系统理论的灰色关联分析方法建立能源结构一产业结构协调度定量评价模型,引入熵权法客观赋权,根据各个指标值的变异程度,引用信息熵所反映数据本身的效用值来计算指标的权重系数,有效地避免了由于人的主观因素而形成的权重分配偏差。研究表明从1990年至2007年之间,中国的能源结构一产业结构协调度值经历了增长——下降——再增长的波浪演进过程,目前的能源结构与产业结构并没有达到充分的良性互动作用。研究结论为中国能源结构一产业结构协调度评价的解析化、定量化提供了有力的手段和理论参考依据。     

淄博市SO2与PM10垂直空间变化规律及其相关性分析

本文对淄博市环境空气中主要污染物SO2和PM10在不同高度的浓度值进行分析,找出污染物垂直空间分布规律;并利用SO2和PM10日均浓度值分析两者之间的相关性,为淄博市环境空气质量进一步控制治理提供一定依据。研究结论如下：淄博市垂直空间SO2、PM10浓度变化基本呈随高度增加而逐步降低趋势;同时SO2和PM10浓度呈现较为明显的相关性。为进一步改善淄博市环境空气质量,不仅要在城市规划中充分考虑给城区以自然通风通道,增加城市对污染物扩散稀释的能力,而其要在开展针对建陶、水泥等行业专项行动,降低工业粉尘排放,加强对城区内市政、房地产建筑工地的监督管理,减少道路和建筑扬尘的同时,加强对SO2排放企业尤其燃煤企业的监管力度,控制SO2排放量,也会相应的进一步降低PM10浓度。     

“十五”期间沈阳市煤炭消费与大气污染相关性分析

通过对沈阳市“十五”期间经济发展所引起的煤炭消费量与大气污染之间的关系进行分析后可知,“十五”期间沈阳市煤炭消耗量与大气污染物排放量、大气环境质量均呈现为“负相关性”,经解析,“十五”期间由于沈阳市采取了煤炭管制、推行集中供热提高煤炭使用效率等手段,使得煤炭消费在增长的情况下大气污染物排放量降低、环境空气质量逐步改善,呈现为“负相关性”。