基于无人机可见光影像的绿色植被提取

在分析健康绿色植被光谱特性及无人机可见光影像典型地物各波段像元值差异的基础上,提出一种综合利用红、绿、蓝3个可见光波段信息的新型绿色植被指数——差异增强植被指数（DEVI）.利用该指数及其他8种常见可见光植被指数结合不同阈值方法提取研究区域绿色植被信息,并采用地表真实感兴趣区和基于SVM的监督分类方法进行精度量化评价.结果表明：由DEVI计算的植被指数灰度影像直方图具有良好双峰形态,可利用双峰直方图阈值法快速确定阈值,且阈值一般位于0.9~1之间;同时,DEVI提取精度明显优于其余8种植被指数,且采用双峰直方图阈值法时,总体精度为98.98%,Kappa系数为0.9791,相对误差为1/83.为验证DEVI是否具有良好的可适用性及可靠性,选取3种典型植被覆盖区域进行可行性验证,结果表明：利用DEVI可高精度提取建筑密集区域和植被零散分布区域的绿色植被信息,总体精度分别为98.42%和98.56%,Kappa系数分别为0.9610和0.9635,相对误差分别为1/125和1/91;而植被集中分布区域提取精度略低于上述2种典型区域,总体精度为97.40%,Kappa系数为0.9371,相对误差为1/53.因此,提出的差异增强植被指数——DEVI可以有效、高精度、低成本提取不同植被覆盖典型区域无人机可见光影像中的绿色植被信息,为陆地生态系统中的绿色植被监测研究提供一种可行性方法.     

绿色金融改革政策的碳减排效应

以绿色金融改革创新试验区政策为例,基于2013~2019年间我国280个地级市的面板数据,运用双重差分法识别绿色金融改革政策是否具有碳减排效应以及其作用机制.研究发现,绿色金融改革政策具有显著碳减排效应（平均值为-0.375）,且呈现逐年递增.机制分析发现,绿色金融改革政策主要通过降低能源消耗强度、提升绿色技术创新水平发挥碳减排效应.此外,绿色金融改革政策具有正向溢出效应,绿色金融改革政策的碳减排效应会辐射到试点区域的周边地区.但绿色金融改革政策并未发挥多污染物减排协同效应.基于此,本文提出了扩大改革试验区范围、加大对绿色金融主体的激励和引导以及发挥绿色金融政策协同效应等政策建议.     

盛行梯度风下热力环流对近地空气质量的影响研究

以中纬度沿海城市上海为代表,采用数值模拟方法,分析了海岸线附近污染源排放的大气污染物在盛行梯度风和热力环流耦合作用下的扩散和输送特征,并与忽略海陆温差的理想情况作了对比.结果表明,即使在盛行梯度风主导城市风场时,海陆温差引起的热力环流对海岸线附近流场仍有重要影响,并使近地面污染物浓度时空分布与海陆无温差时截然不同.海陆无温差时,污染物仅向盛行梯度风的下风向区域扩散.而在海陆有温差时,污染物的扩散却可能是双向的.陆地最高和最低气温出现的时间分别对应着沿海城市污染物最不利释放时段(RTS-16:00和RTS-04:00),造成的污染总时长和日平均浓度均最大,不仅部分近地面污染物被海陆热力环流携带至盛行梯度风的上风向区域,并且下风向区域的日平均浓度最高达海陆无温差时的4~5倍.因此,即使在盛行梯度风较强时忽略海陆温差形成的热力环流影响,也会明显低估非海陆风日的实际污染强度和污染范围.     

成都市夏冬季大气胺颗粒物的单颗粒质谱研究

基于单颗粒气溶胶质谱（SPAMS）对成都市夏冬两季大气胺颗粒进行了综合观测,结合ART-2a算法及人工合并,2个季节大气中的胺颗粒都可分为7类,各类颗粒贡献的季节差异明显,燃烧源颗粒（如EC）在夏季贡献较大,而老化的有机碳颗粒（OCa）贡献在冬季显著升高.两季节平均质谱差减进一步证明夏、冬季分别以燃烧源和老化的胺颗粒为主.因高温分解,夏季胺颗粒占比在正午出现明显的低值,而下午的燃烧活动（如生物质燃烧）对该占比提升作用明显;冬季胺颗粒占比在白天显著高于夜间.随污染加重,胺颗粒数在夏冬两季均快速增加,其中夏季EC颗粒升高最为明显,污染最重时贡献可达47%;冬季升高最明显的是老化程度更高的OCa颗粒,当PM_2.5浓度达到200μg/m³以上时,其贡献比例可达37%.因此,由于污染源和气候条件的差异,成都市大气胺颗粒形成机制和理化特征季节差异巨大.     

我国稀土资源开发利用的环境成本及空间差异特征

稀土开发利用环境成本核算对于我国稀土定价机制改革具有重要参考价值.利用污染普查中的典型企业、稀土年鉴等多种数据源,基于环境治理成本法,核算了2013年我国三大稀土矿区冶炼污染物产生量及环境治理成本（注:涉及"全国"的各要素范围均未包含港澳台地区）,并分析了其空间分布特征.结果表明:① 我国稀土冶炼污染物空间分布特征为北方包头混合型稀土矿以大气污染为主,南方离子型稀土矿以水污染为主,尤其是氨氮污染严重. ② 2013年,我国稀土冶炼环境成本总计为28729×104元,其中废水、废气和固体废物的环境成本分别为49.8%、19.0%和31.2%.我国稀土冶炼环境成本92.9%集中在北方轻稀土矿区,7.1%在南方离子型稀土矿区. ③ 我国稀土冶炼环境代价高,尤其是北方轻稀土矿.包头混合型矿单位稀土氧化物冶炼的环境成本为4135元/t,占氧化铈和氧化镧市场价格的38.8%和41.4%左右,南方离子型稀土矿单位稀土氧化物冶炼的环境成本为2824元/t,占氧化钇市场价格10.9%.      

对羟基苯甲酸酯雌激素活性物种差异的理论研究

受体功能区结构的分化是导致部分环境污染物内分泌干扰效应种间选择性的主要原因之一.本研究采用同源模建的方法构建了青鳉的雌激素受体α亚型(medERα)配体结合区的三维结构,并与人的hERα结构进行比对.在此基础上,经过分子对接分析了对羟基苯甲酸酯类化合物及其含氯衍生物与两个物种ERα作用模式的差异及其分子基础,并基于此提...     

两种常用高分子材料外观颜色评价方法的比较

产品外观颜色的评价一直是高分子材料及制品质量检验中的一个重要项目.目前,关于颜色测试的方法主要有1976年国际照明协会(CIE)推荐的CIE LAB色差公式法和纺织品色牢度试验评定变色用灰色样卡法,两种方法在纺织印染、涂料、高分子材料加工、化工等行业中均得到了广泛的应用,本文详细分析了两种方法的原理、应用和特点.     

Evaluating weather effects on interannual variation in net ecosystem productivity of a coastal temperate forest landscape: A model intercomparison

Forest productivity is strongly affected by seasonal weather patterns and by natural or anthropogenic disturbances. However weather effects on forest productivity are not currently represented in inventory-based models such as CBM-CFS3 used in national forest C accounting programs. To evaluate different approaches to modelling these effects, a model intercomparison was conducted among CBM-CFS3 and four process models (ecosys, CN-CLASS, Can-IBIS and 3PG) over a 2500 ha landscape in the Oyster River (OR) area of British Columbia, Canada. The process models used local weather data to simulate net primary productivity (NPP), net ecosystem productivity (NEP) and net biome productivity (NBP) from 1920 to 2005. Other inputs used by the process and inventory models were generated from soil, land cover and disturbance records. During a period of intense disturbance from 1928 to 1943, simulated NBP diverged considerably among the models. This divergence was attributed to differences among models in the sizes of detrital and humus C stocks in different soil layers to which a uniform set of soil C transformation coefficients was applied during disturbances. After the disturbance period, divergence in modelled NBP among models was much smaller, and attributed mainly to differences in simulated NPP caused by different approaches to modelling weather effects on productivity. In spite of these differences, age-detrended variation in annual NPP and NEP of closed canopy forest stands was negatively correlated with mean daily maximum air temperature during July-September (T_amax) in all process models (R² = 0.4-0.6), indicating that these correlations were robust. The negative correlation between T_amax and NEP was attributed to different processes in different models, which were tested by comparing CO₂ fluxes from these models with those measured by eddy covariance (EC) under contrasting air temperatures (T_a). The general agreement in sensitivity of annual NPP to T_amax among the process models led to the development of a generalized algorithm for weather effects on NPP of coastal temperate coniferous forests for use in inventory-based models such as CBM-CFS3: NPP′ = NPP − 57.1 (T_amax − 18.6), where NPP and NPP′ are the current and temperature-adjusted annual NPP estimates from the inventory-based model, 18.6 is the long-term mean daily maximum air temperature during July-September, and T_amax is the mean value for the current year. Our analysis indicated that the sensitivity of NPP to T_amax was nonlinear, so that this algorithm should not be extrapolated beyond the conditions of this study. However the process-based methodology to estimate weather effects on NPP and NEP developed in this study is widely applicable to other forest types and may be adopted for other inventory based forest carbon cycle models.     

The Relationship Between the Difference in Prismatic Refractive Power of an Eye-and-Face Protector and Its Thickness,Radius of Curvature,and Material

With the help of the research results presented here and on the basis of a graphic analysis we aim to prove the existence of a relationship between the difference in prismatic refractive power and the thickness, curvature radius, and type of material used for panoramic oculars in protective spectacles, goggles, and face shields. The difference in the prismatic refractive power is a fundamental optical characteristic of a protective ocular without corrective effect. According to Standard No. EN 165:1995 (European Committee for Standardization, 1995) the difference in the prismatic refractive power is a difference in the prismatic effect at 2 observation points of an eye-protector.     

Gendered dimensions of climate change response in Swedish municipalities

This article elaborates on and discusses gendered dimensions of climate change response in Swedish municipalities. There are indications that attitudes and behaviour to the environment and climate change are gendered. This evidence together with our own work further indicates that gender awareness is most probably an important influence on how municipalities respond to climate change. The aim of this study was to investigate if and how gendered aspects of climate change response are integrated in the Swedish response to climate change. The potential causal relationships between a high level of awareness of the gendered aspects of climate change and the levels of climate change response were investigated. We asked whether there is a positive relationship between gender awareness and the quality of the communities' climate change policies and practice. Indications of such a relationship prompt a change in research priorities – paying more attention to gender – and in subsequent policy developments.