Scaling Uncertainties in Estimating Canopy Foliar Maintenance Respiration for Black Spruce Ecosystems in Alaska

A major challenge confronting the scientific community is to understand both patterns of and controls over spatial and temporal variability of carbon exchange between boreal forest ecosystems and the atmosphere. An understanding of the sources of variability of carbon processes at fine scales and how these contribute to uncertainties in estimating carbon fluxes is relevant to representing these processes at coarse scales. To explore some of the challenges and uncertainties in estimating carbon fluxes at fine to coarse scales, we conducted a modeling analysis of canopy foliar maintenance respiration for black spruce ecosystems of Alaska by scaling empirical hourly models of foliar maintenance respiration (R_m) to estimate canopy foliar R_m for individual stands. We used variation in foliar N concentration among stands to develop hourly stand-specific models and then developed an hourly pooled model. An uncertainty analysis identified that the most important parameter affecting estimates of canopy foliar R_m was one that describes R_m at 0 ^∘C per g N, which explained more than 55% of variance in annual estimates of canopy foliar R_m. The comparison of simulated annual canopy foliar R_m identified significant differences between stand-specific and pooled models for each stand. This result indicates that control over foliar N concentration should be considered in models that estimate canopy foliar R_m of black spruce stands across the landscape. In this study, we also temporally scaled the hourly stand-level models to estimate canopy foliar R_m of black spruce stands using mean monthly temperature data. Comparisons of monthly R_m between the hourly and monthly versions of the models indicated that there was very little difference between the estimates of hourly and monthly models, suggesting that hourly models can be aggregated to use monthly input data with little loss of precision. We conclude that uncertainties in the use of a coarse-scale model for estimating canopy foliar R_m at regional scales depend on uncertainties in representing needle-level respiration and on uncertainties in representing the spatial variability of canopy foliar N across a region. The development of spatial data sets of canopy foliar N represents a major challenge in estimating canopy foliar maintenance respiration at regional scales.     

石灰石/石灰湿法烟气脱硫结垢的机理及控制

介绍了石灰石/石灰湿法烟气脱硫的工艺原理, 分析了脱硫系统运行过程中存在的不同结垢类型及其机理,提出了解决结垢的可行方法.对工业设计、施工及管理有一定指导和帮助.     

基于相空间重构理论的天津市近海水质混沌特性研究

针对我国近海水质污染呈现的复杂非线性特征,通过对混沌理论中的相空间重构方法进行研究,提出了一种新的完全基于环境监测数据的近海水质分析方法。以天津市近岸海域为例,首先,根据相空间重构理论,对近海各监测点的1维COD时间序列进行多维相空间重构,求得最佳嵌入维数mmin和吸引子关联维数D;然后,采用Wolf方法计算最佳嵌入维数mmin下重构相空间的最大Lyapunov指数λ1。计算结果显示各个监测点的关联维数D均在3.3左右,最大Lyapunov指数λ1均大于0,表明近海水质COD时间序列具有明显的混沌特征,近海水质系统是一个多维系统,貌似随机无规律的近海水质系统具有内在的、固有的规律。应用表明,该方法实用性强,为进一步采用混沌理论对近海水质进行预测提供了理论依据,非常有利于近海水环境的管理。     

基于地基遥感的杭州地区气溶胶光学特性

利用2012年杭州、桐庐、建德、淳安CE-318太阳光度计的观测资料,反演获得了气溶胶光学厚度（AOD）、Ångström波长指数（AE）、单次散射反照率（SSA）和气溶胶粒子谱（ASD）等参数,分析了杭州地区气溶胶光学特性的变化规律.结果表明,2012年杭州、桐庐、建德、淳安AOD_440nm年均值分别为0.94±0.16、0.84±0.17、0.82±0.22、0.71±0.20,呈现出自东北向西南逐渐下降的变化趋势,是长三角地区AOD高值地区之一.AE_440-870nm年均值分别为1.24±0.12、1.19±0.17、1.06±0.04、1.04±0.10,表明杭州地区以半径较小的气溶胶粒子为主控模态.3~4月AE相对偏低与来自北方的沙尘粒子远距离输送有关.除淳安外,杭州、桐庐和建德AOD有明显的日变化特征.不同地区细模态粒子峰值半径春季、秋季和冬季均在0.15 μm左右,由于气溶胶粒子的吸湿增加导致夏季细模态粒子的峰值半径在0.25 μm左右;粗模态粒子峰值半径夏季、秋季和冬季均在2.94 μm左右,高于春季（1.7~2.2 μm）.SSA_440nm年均值分别为0.91±0.01、0.92±0.03、0.92±0.02、0.93±0.02,说明杭州地区气溶胶粒子为中等强度吸收性气溶胶.对气溶胶类型进行分类表明,杭州以生物质燃烧/城市工业型为主,而桐庐、建德和淳安以混合型为主.     

残余聚合物对油田污水的结垢影响研究

主要采用碳酸钙沉积法和硬垢量测定法,考察了聚合物分子量和浓度对旅大(LD)10-1油田采出水结垢的影响规律.实验结果表明:温度对含聚污水体系的结垢状况有一定的影响,温度升高增强了溶液的结垢趋势.由于聚合物与乙二胺四乙酸二钠(EDTA-2Na)之间的螯合竞争作用,随着聚合物浓度的增加,钙离子浓度总体呈增加趋势,硬垢量呈减...     

改进层次分析法评价区域工业污染源

为了保证区域环境与社会经济的可持续发展,从环境、经济和社会的整体效益出发,对区域工业污染源进行系统分析、评价,并进行宏观控制本文基于环境、经济和社会三效益指标的系统要素影响,设计一种定性与定量相结合描述判断矩阵的多指标决策的层次分析法来IF价了业污染源,克服了等标污染负荷法只考虑主控污染因子排放总量的单一性以及层次分析法量化标度时产生的主观性影响,评价结果较为合理     

贵阳城市生活污水对不锈钢腐蚀、结垢研究

污水成分复杂,会对不同材料产生不同腐蚀和结垢,影响污水热能技术的应用推广。为验证污水对不锈钢的腐蚀、结垢作用,结合不锈钢的腐蚀机理,设计不同流速的城市生活污水对不锈钢片影响实验,并应用数码相机观察、扫描电子显微镜的能谱分析等方法,观察不锈钢片表面变化情况,以及表面污垢成分,证明了贵阳地区的生活污水对不锈钢的腐蚀、结垢作用较小。不锈钢是贵阳及高原喀斯特地区污水热能应用热交换器材质的良好选择。     

基于指标规范值的环境质量突变模糊普适指数公式

针对传统突变模糊归一化公式的问题,在适当设定指标参照值和指标值的规范变换式基础上,使同类环境不同指标同级标准的规范值差异尽可能小,而不同标准的指标规范值差异尽可能大,从而可以认为用规范值表示的同类环境的各指标皆等效于某个规范指标。而任意m项指标的突变模型可用多个尖点突变(m=2)和(或)燕尾突变(m=3)两种突变模型组合表示,且具有可规范的指数分级标准值。基于指标规范值的环境质量突变模糊指数公式具有普适、统一和简单、适用的特点。     

Signal-transfer modeling for regional assessment of forest responses to environmental changes in the southeastern United States

Stochastic transfer of information in a hierarchy of simulators is offered as a conceptual approach for assessing forest responses to changing climate and air quality across 13 southeastern states of the USA. This assessment approach combines geographic information system and Monte Carlo capabilities with several scales of computer modeling for southern pine species and eastern deciduous forests. Outputs, such as forest production, evapotranspiration and carbon pools, may be compared statistically for alternative equilibrium or transient scenarios providing a statistical basis for decision making in regional assessments. This revised version was published online in July 2006 with corrections to the Cover Date.     

絮凝作用对HEDP防垢性能的影响

絮凝剂ＰＨＰ、防垢剂ＨＥＤＰ是油田水处理常用的药剂。在油田水处理过程中，调节污水的ＰＨ、投加絮凝剂常常与投加防垢剂一起或先后进行。本文对投加絮凝剂和调节ＰＨ对防士兵防垢性能的影响进行了研究。实验结果证明，絮凝剂的絮凝作用和ＰＨ调节产生的Ｆｅ（ＯＨ）２，均会使污水中的ＨＥＤＰ含量发生变化，防垢性能受到影响。