非正态概率分布的大气污染物监测数据处理方法

从概率基本公式出发，在偏态分布的约束条件下，经数学推导；建立概率积分式。通过合成氨厂大气中污染物落地浓度的计算，并与监测数据进行相关处理实例看，相关系数０．９９９。该方法适用于偏态分布大气污染物落地浓度的概率计算及预测，可供环境监测、环境管理及研究人员对大气质量分析、评价的参考和借鉴     

长沙市人为源大气污染物排放清单及特征研究

根据收集的长沙市人为源活动水平数据,建立了该地区2014年1 km×1 km人为源大气污染物排放清单.结果显示,2014年长沙市SO_2、NO_x、CO、PM_(10)、PM_(2.5)、BC、OC、VOCs和NH_3排放总量分别为53.5×10~3、78.3×10~3、284.6×10~3、102.3×10~3、42.1×10~3、4.0×10~3、7.2×10~3、64.2×10~3、27.1×10~3t.化石燃料固定燃烧源为最大的SO_2排放贡献源,道路移动源是主要的NO_x贡献源,CO排放主要来自化石燃料固定燃烧源和道路移动源,长沙市VOCs的最大贡献源是溶剂使用源,PM_(10)、PM_(2.5)最主要的排放源是扬尘源,BC最大的排放贡献源为化石燃料固定燃烧源,生物质燃烧源是最大的OC贡献源,NH_3排放主要来源于畜禽养殖和农业施肥.空间分布结果显示,长沙市NH_3的排放在宁乡县、望城区、长沙县、浏阳市分布较多,主要呈现片状分布.其他污染物排放高值区则主要分布在中心城区、工业区及道路分布区域.     

应用物种敏感性分布法对太湖沉积物中多环芳烃的生态风险分析

多环芳烃(PAHs)具有高的疏水性,在水体中优先分布于沉积物.采用物种敏感性分布法(SSDs法),依据水生生物慢性毒性数据计算5%物种危害浓度(HC5);并结合欧盟委员会风险评价技术导则(TGD)进而得到沉积物预测无效应浓度(PNEC-sed),以报道的太湖的沉积物中浓度数据作为预测环境浓度(PECsed);用商值法P...     

基于GIS的震害空间分布图集的设计与编制

快速地生成震害分布预测图,对提高减灾救灾能力有着重要意义.本研究采用3S(地理信息系统-GIS、全球定位系统-GPS和遥感-RS)技术,设计了一套全方位、多角度、综合自然环境、社会经济和人文要素的震害空间分布图集.本文将GIS强大的空间分析和数据管理能力与GPS、RS和地震科学相结合,从设计思想、图集内容、表现形式等方...     

VELOCITY DISTRIBUTIONS IN STREAMBED SIMULATION CULVERTS USED FOR FISH PASSAGE1

ABSTRACT: Stream crossings designed to simulate a natural streambed inside a culvert are commonly used to meet criteria where fish passage is required. Currently, there has been little research that quantitatively examines the flow patterns within these streambed simulation culverts. A model is presented that estimates the percent of a cross section that is within the swimming ability of juvenile fish developed from velocity measurements on first‐generation stream simulation culverts — those culverts with a continuous gravel bed. The model, developed with regression techniques, uses physical and hydraulic parameters including discharge, total cross sectional area, Froude number, and relative roughness, and was tested directly against velocity distributions computed from field measurements and in a culvert design mode. Results were favorable, although larger percentage errors exist, particularly at small flow depths. The model appears to underestimate the percent of channel cross section at or below a limiting velocity, hence it is generally conservative in design mode.     

Optimizing the horizontal structural diversity in uneven-aged northern hardwood stands

Two mathematical programming formulations are presented which allow the determination of diameter distributions that maximize the diameter class diversity in uneven-aged northern hardwood stands. Distributions generated from these models were found to be comparable from a management standpoint and could be incorporated into existing linear programming models as alternative management scenarios. The models presented here provide an initial framework for quantitatively addressing the requirements of the US National Forest Management Act in matters of diversity in the planning process.     

基于GTWR-XGBoost模型的四川省PM2.5小时浓度估算

卫星气溶胶光学厚度(AOD)和气象数据已被广泛用于估算空气动力学直径≤2.5μm的地表颗粒物(PM_2.5)浓度.研究高时间分辨率、高精度的PM_2.5浓度估算方法,对及时准确的空气质量预报和大气污染的预防及缓解具有重要意义.使用Himawari-8 AOD小时产品和ERA5气象再分析资料作为估算变量,提出GTWR-XGBoost组合模型,对四川省PM_2.5小时浓度进行估算.结果表明：(1)提出的组合模型运用于全数据集的性能优于KNN、 RF、 AdaBoost、 GTWR、 GTWR-KNN、 GTWR-RF和GTWR-AdaBoost模型,拟合精度指标R²、 MAE和RMSE分别为0.96、 3.43μg·m^-3和5.52μg·m^-3,验证精度指标R²、 MAE和RMSE分别为0.9、 4.98μg·m^-3和7.92μg·m^-3.(2)该模型作用于PM_2.5浓度小时估算...     

城市自然灾害风险评价的一级模型

本文分析了以往概率风险存在的问题,用模糊集手段定义了城市自然灾害的可能性风险,并提出了一级综合评价模型。本文提供的方法,由于能较广泛地对有关信息进行分析,从而可提高风险评价的可行性和可能性。     

Evaluating complementary networks of restoration plantings for landscape‐scale occurrence of temporally dynamic species

Multibillion dollar investments in land restoration make it critical that conservation goals are achieved cost‐effectively. Approaches developed for systematic conservation planning offer opportunities to evaluate landscape‐scale, temporally dynamic biodiversity outcomes from restoration and improve on traditional approaches that focus on the most species‐rich plantings. We investigated whether it is possible to apply a complementarity‐based approach to evaluate the extent to which an existing network of restoration plantings meets representation targets. Using a case study of woodland birds of conservation concern in southeastern Australia, we compared complementarity‐based selections of plantings based on temporally dynamic species occurrences with selections based on static species occurrences and selections based on ranking plantings by species richness. The dynamic complementarity approach, which incorporated species occurrences over 5 years, resulted in higher species occurrences and proportion of targets met compared with the static complementarity approach, in which species occurrences were taken at a single point in time. For equivalent cost, the dynamic complementarity approach also always resulted in higher average minimum percent occurrence of species maintained through time and a higher proportion of the bird community meeting representation targets compared with the species‐richness approach. Plantings selected under the complementarity approaches represented the full range of planting attributes, whereas those selected under the species‐richness approach were larger in size. Our results suggest that future restoration policy should not attempt to achieve all conservation goals within individual plantings, but should instead capitalize on restoration opportunities as they arise to achieve collective value of multiple plantings across the landscape. Networks of restoration plantings with complementary attributes of age, size, vegetation structure, and landscape context lead to considerably better outcomes than conventional restoration objectives of site‐scale species richness and are crucial for allocating restoration investment wisely to reach desired conservation goals.