基于最大熵模型的福建省红树林潜在适生区评估

本研究利用生物气候、地形、底质类型、海温等环境因子和红树林分布数据建立了福建省红树林分布模型,基于最大熵方法分析了福建省沿岸红树林潜在适生区的空间分布.根据模型输出结果对福建省红树林的生境适宜性进行了评估,识别了影响红树林分布的关键环境因子及其适生值区间,并通过空间叠加分析获取了福建省红树林保护与修复的优先区与空缺区域.结果表明,影响福建省红树林适生区分布格局的主要环境因子包括海表温度、气温和降水等,福建省红树林潜在适生区主要位于沙埕港-三沙湾-兴化湾沿岸、泉州湾-厦门湾-九龙江口沿岸、漳江口-东山湾沿岸等地,其中最优适生区面积约为91km².全省共识别出8处红树林保护与修复的优先区域,现存红树林保护率约为64.4%,保护修复空缺主要出现在沙埕港、三沙湾、罗源湾、福清湾等处,研究结论可为未来福建省红树林保护和修复行动提供科学参考.     

鄱阳湖水位-淹水面积关系不确定性的分析

湖泊淹水范围的时空变化特征往往决定了湖泊湿地的景观结构和功能。鄱阳湖是我国最大淡水湖,水位和淹水范围的季节变化悬殊,鄱阳湖淹水特征对研究鄱阳湖湿地生态系统的结构与功能都具有显著意义,过去很多研究关注鄱阳湖水位-淹水面积关系,不同的研究者得到的水位-淹水面积关系各有差异,表现出一定的不确定性。利用多时相的卫星遥感影像提取的鄱阳湖水面面积的基础上,结合鄱阳湖长时间序列的水位观测资料,探讨鄱阳湖水位-淹水面积关系不确定的原因。研究结果表明:(1)尽管鄱阳湖水面面积与水位表现分段线性关系,但在相同水位条件下,鄱阳湖水面面积表现出较大的不确定性;(2)鄱阳湖水位表现南高北低的空间异质性格局,随着水位增加,鄱阳湖水位的空间异质性降低,并且水面坡降具有季相性,相同水位下退水期的水面坡降大于涨水期的水面坡降;(3)受洲滩地形和"堑秋湖"渔业方式的影响,相同水位下退水期出露洲滩中子湖泊的水面范围大于涨水期中子湖泊水面范围;(4)此外,鄱阳湖采砂显著改变采沙场的湖盆地形,从而改变低水位下的主要采沙场的淹水范围。综上所述,鄱阳湖水位-淹水面积关系的不确定性除了受湖盆地形、"五河"来水、长江顶托等自然原因,还有采砂和堑秋湖渔业方式等人类活动的原因。     

沈阳一次严重污染天气过程持续和增强气象条件分析

2015年11月7-9日沈阳出现罕见的持续严重污染天气,采用环流形势、地面常规气象观测、污染物浓度观测、风廓线雷达及雨滴谱资料等,对此次污染成因进行了研究.结果表明:在此次严重污染天气过程中,连续22 h AQI≥500,首要污染物均为PM_2.5,其异常峰值最高达到1308μg/m3;ρ（PM_2.5）与ρ（PM₁₀）、ρ（NO₂）和ρ（CO）的相关系数分别达到0.996、0.602、0.891,并且ρ（PM_2.5）与ρ（PM₁₀）、ρ（CO）的正相关性更为显著;在污染的同时出现了降水,11月7和8日的日降水量分别为9.9和2.3 mm,但降水对污染物的稀释和清除作用并不明显.稳定的大尺度环流和对流层内中低层大气层结持续稳定、连续4个时次的探空曲线显示925~850 hPa之间存在多个逆温层（逆温强度最大可达5℃）、相对湿度较大（日均相对湿度在75%以上）,是此次严重污染天气持续的有利气象条件.风廓线雷达探测的整层大气垂直速度很小,多介于-1~1 m/s之间,并且近地面2 m/s以下弱下沉的垂直速度为严重污染天气过程提供了较好的动力条件.此外,近地面风力可达3~4级,有利于上游污染物的水平输送.研究显示,此次严重污染天气过程还与外围秸秆集中燃烧所导致的大量污染物长距离输送有密切关联.      

黄河口治理与“三约束”理论

黄河口治理是黄河治理的重要问题之一,黄河口治理观点有河口提动论、河口相对稳定论、固住河口论。本文分析了固住河口的必要性和可行性,提出了“三约束”理论,认为黄河口治理关键是固住河口。     

室内空气中的气态多环芳烃的被动采样监测

利用自制被动采样装置,在2011年秋冬季对南京市部分地区室内空气中5种气态多环芳烃(PAHs)(萘、苊烯、苊、芴、菲)进行了为期100d的连续采样检测,被动采样器的采样速率为0.012m3/d,5种PAHs的回收率在63%～105%之间,方法检出限在1.1～2.4ng范围内。结果表明,南京市5处不同室内环境空气中萘的浓度最高,占总量的90%以上。室内环境空气中5种PAHs的总浓度为230～1564ng/m3。住宅内人体对5种PAHs的暴露速率为479～560ng/h。     

Impacts of emissions and meteorological changes on China’s ozone pollution in the warm seasons of 2013 and 2017

O₃ increment is mainly caused by changes in meteorology rather than emissions. Emission reduction is effective to reduce O₃ nationwide, especially in summer. Strengthened NO_x controls are necessary to meet the ambient O₃ standard. We have quantified the impacts of anthropogenic emissions reductions caused by the Air Pollution Control Action Plan and changes in meteorological fields between 2013 and 2017 on the warm-season O₃ concentration in China using a regional 3D chemical transport model. We found that the impact on daily maximum eight-hour (MDA8) O₃ concentration by the meteorological variation that mostly increased O₃ was greater than that from emission reduction, which decreased O₃. Specifically, the control measures implemented since 2013 in China have reduced SO₂, NO_x, PM_2.5, and VOC emissions by 33%, 25%, 30%, and 4% in 2017, while NH₃ emissions have increased by 7%. The changes in anthropogenic emissions lowered MDA8 O₃ by 0.4–3.7 ppb (0.8%–7.6%, varying by region and month), although MDA8 O₃ was increased slightly in some urban areas (i.e. North China) at the beginning/end of warm seasons. Relative to 2013, the average 2 m temperature in 2017 shows increments in North, North-east, East, and South China (0.34℃–0.83℃) and decreases in Central China (0.24℃). The average solar radiation shows increments in North, North-east, and South China (7.0–9.7 w/m²) and decreases in Central, South-west, and North-west China (4.7–10.3 w/m²). The meteorological differences significantly change MDA8 O₃ by -3.5–8.5 ppb (-8.2%–18.8%) with large temporal variations. The average MDA8 O₃ was slightly increased in North, North-east, East, and South China. The response surface model suggests that the O₃ formation regime transfers from NO_x-saturated in April to NO_x-limited in July on average in China.     

气相色谱-质谱法测定大气中98种挥发性有机物

通过色谱-质谱联用法(简称GC-MS),利用低温冷阱技术对大气中的VOCs进行浓缩富集,然后经过加热解吸分别至毛细管色谱柱和FID检测器及MS检测器,对大气中98种挥发性有机化合物(VOCs)进行分离、定性、定量测定。方法检出限为0.008×10-9~0.100×10-9(V/V);线性相关系数的平方值为0.992 7~1,相对标准偏差为4.0%~20.2%,总体标准偏差为0.154 2~0.952 1。     

Levels and distribution of Dechloranes in sediments of Lake Taihu,China

The occurrence and spatial distribution of dechloranes including mirex, dechlorane plus (DP), dechlorane (Dec) 602, Dec 603, and Dec 604 in surficial sediments of Lake Taihu were investigated in this study. The concentrations of mirex and DP ranged from below detection limit (BDL) to 1.29 ng g^?1 dw and 0.051 to 2.10 ng g^?1 dw, respectively. Dec 602, Dec 603, and Dec 604 on the other hand, were BDL in any of the samples. The contamination levels of DP were higher than that of Mirex at 21 of all 22 sampling sites. Levels of mirex and DP in the lake sediments were correlated when an extremely high mirex value was removed. Both mirex and DP levels were correlated with the amount of organic matters in the sediment samples. Spatial distribution of mirex and DP suggested that these two chemicals in the lake had similar input sources except for one site. Comparison to previously reported flame retardants’ levels in the sediments shows that DP levels were similar with the levels of tetrabromobisphenol A, hexabromocyclododecane but lower than PBDEs and organophosphates levels in Lake Taihu. The higher levels in the north-east part of Lake Taihu adjacent to two major cities: Wuxi and Suzhou, indicated that city effluent might be a major source for DP contamination in the lake.     

房地产开发地铁振动达标距离研究

已建和待建的多条地铁线路穿过某房地产开发地块,为了防治地铁运行对建筑造成振动环境影响,需要设定建筑靠近地铁的最小达标距离,包括采取减振措施后的距离。通过现场系统实验监测结合数值模型分析,从工程实践的角度提出了上述距离。对于实验中观察到随距离出现振动局部放大以及进口与国产仪器监测结果不同的现象,佐证了有关学者的理论与实验分析,提出:(1)现有地铁环境影响评价报告常用的60m评价范围偏小,推荐可扩大至80~100m;(2)迫切需要新的振动环境标准发布,避免有关项目的环境管理要求偏低。