基于ERA-Interim资料分析青藏高原“湿池”变化特征

论文利用ERA-Interim(0.5°×0.5°,简称ERA)、NCEP/NCAR2(2.5°×2.5°,简称NCEP2)两种不同分辨率的再分析资料和探空观测资料,首先分析了夏季(7月)和冬季(1月)青藏高原(以下简称高原)上大气水汽含量大值区(简称"湿池")的区域分布特征,然后基于ERA资料分析了1979—2012年间高原"湿池"的一些变化特征,发现了一些新的事实。主要结果包括:在对流层中上层,高原上无论夏、冬季都有大气水汽含量的高值中心——高原"湿池"存在。夏季7月高原"湿池"强度最强,ERA资料除了在高原南部有自西到东的连续高湿中心带外,在高原西北部还有一个高湿中心;NCEP2资料仅在高原东南部和西南部有两个高湿中心。冬季1月,两种资料均只在高原东南部有高湿中心。总体上,ERA资料与探空观测资料的高湿中心区更为接近。7月,高原南部高湿中心在1990年代中期(1994—1996年)之后持续偏强,西北部中心强度有弱—强—弱—强交替变化特征;1月,高湿中心在1980年代末期开始持续偏强。高原南部高湿中心带在7月几乎是一个连续的区域,1996年以后这一特征更为明显,在1月则是分为东西两段的高湿中心带。     

Water chemistry controlled aggregation and photo-transformation of silver nanoparticles in environmental waters

The inevitable release of engineered silver nanoparticles (AgNPs) into aquatic environments has drawn great concerns about its environmental toxicity and safety. Although aggregation and transformation play crucial roles in the transport and toxicity of AgNPs, how the water chemistry of environmental waters influences the aggregation and transformation of engineered AgNPs is still not well understood. In this study, the aggregation of polyvinylpyrrolidone (PVP) coated AgNPs was investigated in eight typical environmental water samples (with different ionic strengths, hardness, and dissolved organic matter (DOM) concentrations) by using UV–visible spectroscopy and dynamic light scattering. Raman spectroscopy was applied to probe the interaction of DOM with the surface of AgNPs. Further, the photo-transformation and morphology changes of AgNPs in environmental waters were studied by UV–visible spectroscopy, inductively coupled plasma mass spectrometry, and transmission electron microscopy. The results suggested that both electrolytes (especially Ca^2 + and Mg^2 +) and DOM in the surface waters are key parameters for AgNP aggregation, and sunlight could accelerate the morphology change, aggregation, and further sedimentation of AgNPs. This water chemistry controlled aggregation and photo-transformation should have significant environmental impacts on the transport and toxicity of AgNPs in the aquatic environments.     

阜新市空气监测点位优化的聚类分析

基于聚类分析法利用数据之间距离系数进行分类的原理,建立空气监测点位聚类分析优化模型,结合阜新市地形、气象及历史监测数据,进行阜新市空气监测点位布设优化应用,优化结果表明:距离相似水平取d=0.3时,环保局(B点)与人民公园(C点)监测点空气污染物浓度分布相似性最高,合并为1点,增设气象台监测点位作为清洁背景点,4个点位构成阜新市空气监测新网络;利用CALPUFF模型模拟对优化后监测点位进行相关性检验。检验结果表明:监测点位优化后SO2浓度与实测值相关系数为0.984,PM10相关系数为0.968,NO2相关系数为0.973。CALPUFF模型模拟值与实际监测值之间相关系数均大于0.75,表明优化后的阜新市空气监测点位具有客观环境代表性;监测点位优化与检验方法具有一定应用价值。     

Wood carbon content of tree species in Eastern China: interspecific variability and the importance of the volatile fraction

Data on the mass density and carbon content of tree organs, and in particular stem wood, are essential for accurate assessments of forest carbon sequestration. However most available data, including that for East Asia, has neglected the volatile C fraction. Wood samples were collected and assayed for C content from 14 native tree species in Jilin Province, NE China. C content showed statistically significant variation among species, ranging from 48.4% to 51.0%. The volatile C fraction was non-negligible, averaging 2.2%, and showed high variation among species. As found in prior studies, wood C content was appreciably higher in conifer than hardwood (angiosperm) species (50.8+/-0.1% vs. 49.5+/-0.2%, respectively). Wood carbon density (gC/cm(3)) showed very high inter-specific variation, due mainly to differences in wood specific gravity. Our analyses, in conjunction with recently published data from North America, indicate a global mean value of 47.5+/-0.5% wood C content exclusive of volatile C; the widely used 50% figure corresponds more closely to total wood C inclusive of the volatile fraction. Failure to include volatile C or to use species- or higher-taxon-specific C content values in forest C assessments is likely to introduce biases on the order approximately 4-6%. In addition, the stocks and flows of the volatile C fraction in wood are in themselves an important and sorely neglected aspect of forest C processes likely to be strongly impacted by harvests and other management practices.     

皖南地区铜陵市大气颗粒物污染特征及潜在源研究

利用2018年3月—2021年2月环境和气象数据对皖南地区铜陵市大气颗粒物的污染特征和潜在贡献源进行了系统性研究.铜陵市大气颗粒物污染具有明显的季节变化特征,冬季污染物浓度最高,PM_2.5和PM₁₀平均为（60.3±31.0）μg·m^-3和（89.2±42.2）μg·m^-3.计算发现PM_2.5/PM₁₀超过0.5,铜陵市的大气颗粒物污染问题与细颗粒物关系密切.后向轨迹聚类分析表明铜陵市大气颗粒物的输送路径具有季节性差异.春季以西北、东北和西南方向气流为主,占比83.73%;夏季以东南和南部方向气流为主,占比82.90%;秋季以东北气流为主,占比51.00%;冬季则是以北方和西北气流为主,占比69.81%.其中,冬季气流轨迹所对应的PM_2.5和PM₁₀的浓度最高,平均为59.7和92.0μg·m^-3;夏季最低,平均为23.8和43.8μg·m^-3.潜在源贡献因子（WPSC...     

2021年中国北方首次沙尘天气的多源遥感分析

利用多源遥感数据和NCEP再分析资料,从沙尘源区的地理环境和气候特征出发,对2021年中国北方首次沙尘天气事件每日的大气环流形势以及沙尘的水平,垂直分布特征进行深入的研究分析.结果表明:源区内异常增温,降水稀少的气候背景下致使大面积裸露松散的土壤含水量较低,为大范围,高强度沙尘天气的形成提供了物质基础;频繁活动的冷空气,是沙尘天气爆发的动力因子.沙尘在强风中沿东南方向向下游地区输送和扩散,中国西北,华北,黄淮,江淮,江汉地区和江南北部等地先后受到沙尘天气的影响,空气质量迅速恶化,首要污染物为PM₁₀.此外,沙尘气溶胶东移也波及朝鲜半岛,日本等下游地区.在输送过程中,内陆地区沙尘主要分布在1~6km,而下游地区的沙尘则集中分布在2km高度附近,粒径较大的沙尘出现在近地表的频率较高,较小的颗粒主要分布在对流层中下层.     

民用煤排放PM2.5中碳组分与水溶性离子特征

研究4种典型民用煤燃烧排放PM_2.5中的碳组分以及水溶性离子含量特点,并通过PAM-OFR(潜在气溶胶质量-氧化流动反应器)模拟了大气老化过程(2d)对煤球与烟煤燃烧PM_2.5中碳组分与水溶性离子含量的变化影响。结果表明,烟煤燃放PM_2.5中碳组分含量最高,达到57.96%,其EC含量是其他煤种的4.3~9.6倍。民用煤燃烧产生PM_2.5中水溶性离子以Na⁺与SO₄^2-为主,其在总水溶性离子中占比合计约47%~76%。经历了大气老化试验后,煤球与烟煤燃烧排放PM_2.5中NH₄⁺和NO₃^-离子含量大幅增加,与之相比,TC占PM_2.5比例分别下降了12.03%与19.99%。     

乌鲁木齐树木叶片汞浓度时空特征及环境意义

城市大气环境由于受人为活动影响,具有较高大气汞浓度和时空分布不均一特征。植被叶片虽具有较强富集大气汞的能力,但能否指示城市大气汞时空变化,目前尚有存疑。本文通过连续监测新疆乌鲁木齐市区内6个采样点5种常见树种叶片,在生长季（2019年5～10月）内的汞浓度,分析树叶汞浓度的时空分布变化特征,进而寻找潜在的最优树种叶片,反演乌鲁木齐大气汞污染程度。结果表明,城市内的局地污染能够显著提高叶片汞浓度;树种叶片对大气汞浓度的敏感性存在明显差异（P<0.01）;落叶阔叶树的叶汞浓度与叶片生长时间呈显著正相关关系（P<0.01）,即叶片在整个生长期不断积累大气汞;而针叶汞浓度一年之内与生长时间无显著关系。考虑到圆冠榆叶片对大气汞浓度敏感性较高且分布范围更广,圆冠榆作为乌鲁木齐城市大气汞的生物监测器较为合适。本研究为研究城市大气汞浓度生物监测提供了典型的案例与借鉴。     

海洋大气环境下磷钒系耐候钢腐蚀数据分析

本文通过大气环境暴露试验,研究了在青岛海洋大气环境中暴露10年5周期的4种磷钒系耐候钢的腐蚀规律。结果表明,四种耐候钢的腐蚀速率的关系为:10CrPV10CuPV10MoPV08PV,耐侯钢的耐蚀性与添加元素类别和添加量相关。平均腐蚀深度数据拟合结果表明,A值大小顺序为:10CrPV10CuPV10 MoPV08PV,而n值的顺序是:10CuPV10CrPV10MoPV08PV。