Characteristics of carbonyl compounds in ambient air of Shanghai,China

The levels of carbonyl compounds in Shanghai ambient air were measured in five periods from January 2007 to October 2007 (covering winter, high-air-pollution days, spring, summer and autumn). A total of 114 samples were collected and eighteen carbonyls were identified. Formaldehyde, acetaldehyde and acetone were the most abundant carbonyls and their mean concentrations of 19.40 ± 12.00, 15.92 ± 12.07 and 11.86 ± 7.04 μg m⁻³ respectively, in the daytime for five sampling periods. Formaldehyde and acetaldehyde showed similar diurnal profiles with peak mixing ratios in the morning and early afternoon during the daytime. Their mean concentrations were highest in summer and lowest in winter. Acetone showed reversed seasonal variation. The high molecular weight (HMW, ≥C5) carbonyls also showed obvious diurnal variations with higher concentrations in the daytime in summer and autumn, while they were all not detected in winter. Formaldehyde and acetaldehyde played an important role in removing OH radicals in the atmosphere, but the contribution of acetone was below 1%. The carbonyls levels in high-air-pollution days were reported. More carbonyl species with higher concentrations were found in high-air-pollution days than in spring. These carbonyls were transported with other pollutants from north and northwest in March 27 to April 2, 2007 and then mixed with local sources. Comparing with Beijing and Guangzhou, the concentrations of formaldehyde and acetaldehyde in Shanghai were the highest, which indicated that the air pollution in Shanghai was even worse than expected.     

Adaptation of Pressure Based CFD Solvers for Mesoscale Atmospheric Problems

General purpose Computational Fluid Dynamics (CFD) solvers are frequently used in small-scale urban pollution dispersion simulations without a large extent of ver- tical flow. Vertical flow, however, plays an important role in the formation of local breezes, such as urban heat island induced breezes that have great significance in the ventilation of large cities. The effects of atmospheric stratification, anelasticity and Coriolis force must be taken into account in such simulations. We introduce a general method for adapting pressure based CFD solvers to atmospheric flow simulations in order to take advantage of their high flexibility in geometrical modelling and meshing. Compressibility and thermal stratification effects are taken into account by utilizing a novel system of transformations of the field variables and by adding consequential source terms to the model equations of incompressible flow. Phenomena involving mesoscale to microscale coupled effects can be analyzed without model nesting, applying only local grid refinement of an arbitrary level. Elements of the method are validated against an analytical solution, results of a reference calculation, and a laboratory scale urban heat island circulation experiment. The new approach can be applied with benefits to several areas of application. Inclusion of the moisture transport phenomena and the surface energy balance are important further steps towards the practical application of the method.     

日本虎斑猛水蚤在抑食金球藻中存活、发育和繁殖的实验研究

抑食金球藻(Aureococus anophagefferens)可以形成褐潮, 并对贝类、浮游动物等多种生物均能造成不利影响。为进一步探究抑食金球藻对浮游动物的影响, 本文以日本虎斑猛水蚤(Tigriopus japonicus)为实验生物, 研究抑食金球藻对日本虎斑猛水蚤摄食、存活、生长发育以及繁殖的影响。日本虎斑猛水蚤具有易于在实验室培养、生长周期短、雌雄异体等优点, 是海洋毒性污染物检测的模式生物。实验利用高效液相色谱分析方法, 在日本虎斑猛水蚤体内色素中检测到了抑食金球藻的特征色素19’-丁酰氧基岩藻黄素(But-fuco), 表明日本虎斑猛水蚤能够摄食抑食金球藻。当微藻生物量(相对碳含量)分别同为0.7 μg/mL和7.2 μg/mL时, 在抑食金球藻中无节幼体发育至桡足幼体及成体的存活率均高于以青岛大扁藻为饵料的对照组, 但无显著差异, 并且在前者中无节幼体的发育时间显著低于后者, 12 d内雌体的产卵次数与产卵量显著高于后者。结果表明, 日本虎斑猛水蚤在抑食金球藻中能进行正常的生命活动, 并且是首次报导的一种能够在抑食金球藻中正常摄食、生存、生长发育和繁殖的浮游动物。因此, 当褐潮发生时, 由于贝类幼体等生物会受到显著的不利影响, 日本虎斑猛水蚤等抗性较强的生物可能会成为优势种, 从而会影响浮游动物群落结构的组成, 进而可能会使整个海洋生态系统发生变化。本研究有助于全面了解褐潮对海洋生态系统的影响。     

Structural improvement of age-hardened gypsum-treated bauxite red mud waste using readily decomposable phyto-organics

Several years (7) after incidental lithification by added gypsum, the effect of crushing and phyto-organics on some physical properties of red mud wastes (RMW) was examined under laboratory conditions. It was hypothesized that mechanically breaking up the hardened masses would increase their permeability. However, on the contrary, crushing these rock-hard masses into <2-mm particles did not increase permeability. A phyto-organic treatment on the other hand greatly improved permeability of the crushed entities such that infiltration rates increased from 0 to 10 cm/h. After 24 weeks of incubation, the structure of the newly formed phyto-organically treated gypsum-hardened RMW aggregates was also substantially improved over that of the controls, as a >3-fold increase in resistance to disintegration during wet sieving was exhibited by the phyto-organically treated samples. The increase in water infiltration by combining crushing with phyto-organic applications was ascribed to a decrease in particle dispersion, creating more stable clay clusters, which in turn stabilized channels and pores. Conversely, it was concluded that the singular crushing of gypsum-hardened bauxite waste in the waste dumps is potentially wasteful and ineffective.     

Characteristics of dry-wet abrupt alternation events in the middle and lower reaches of the Yangtze River Basin and the relationship with ENSO

During recent decades, more frequent flood-drought alternations have been seen in China as a result of global climate change and intensive human activities, which have significant implications on water and food security. To better identify the characteristics of flood-drought alternations, we proposed a modified dry-wet abrupt alternation index (DWAAI) and applied the new method in the middle and lower reaches of the Yangtze River Basin (YRB-ML) to analyze the long-term spatio-temporal characteristics of dry-wet abrupt alternation (DWAA) events based on the daily precipitation observations at 75 rainfall stations in summer from 1960 to 2015. We found that the DWAA events have been spreading in the study area with higher frequency and intensity since 1960. In particular, the DWAA events mainly occurred in May and June in the northwest of the YRB-ML, including Hanjiang River Basin, the middle reaches of the YRB, north of Dongting Lake and northwest of Poyang Lake. In addition, we also analyzed the impact of El Niño Southern Oscillation (ENSO) on DWAA events in the YRB-ML. The results showed that around 41.04% of DWAA events occurred during the declining stages of La Niña or within the subsequent 8 months after La Niña, which implies that La Niña events could be predictive signals of DWAA events. Besides, significant negative correlations have been found between the modified DWAAI values of all the rainfall stations and the sea surface temperature anomalies in the Nino3.4 region within the 6 months prior to the DWAA events, particularly for the Poyang Lake watershed and the middle reaches of the YRB. This study has significant implications on the flood and drought control and water resources management in the YRB-ML under the challenge of future climate change.     

考虑水文变异的黄河干流河道内生态需水研究

气候变化及人类活动导致水文变异,变异前后样本总体分布显著不同,即改变了当地生态系统的水文状况,打破生态平衡。本文使用滑动秩和检验(Mann-Whitney U检验) 分析水文变异,并对水文变异成因做了系统的分析。在此基础上,对变异前各月平均流量序列用线性矩法推求GEV分布参数,求出概率密度最大流量,并将其视为相应月河道内生态流量。本文用该法计算黄河干流7 站各月河道内生态流量,即得河道内生态需水情况。分析表明,考虑水文变异的河道内生态需水计算方法是可行的;水文变异后,黄河流域干流各水文站满足生态需水的频率大大降低,汛期降低幅度比非汛期大;黄河生态系统水环境恶化的主要原因是人类活动。     

中国东部植被NDVI对气温和降水的时空响应(英文)

Temporal and spatial response characteristics of vegetation NDVI to the variation of temperature and precipitation in the whole year,spring,summer and autumn was analyzed from April 1998 to March 2008 based on the SPOT VGT-NDVI data and daily temperature and precipitation data from 205 meteorological stations in eastern China.The results indicate that as a whole,the response of vegetation NDVI to the variation of temperature is more pronounced than that of precipitation in eastern China.Vegetation NDVI maxi...     

图们江地区水环境容量及其对区域开发的影响研究

以ＣＯＤ为控制指标,计算了图们江地区５条河流逐月环境容量以及污水达标排放时的允许污水排放量。结果表明,各月环境容量分配极不均匀,丰水期２个月约占５０％,而长达５个月的枯水期环境容量很小,不足全年的１０％;即使以１９９５年污水排放量衡量,污水达标排放时,枯水期图们江干流等５条河流控制断面水质也达不到指定功能水质标准,已无环境容量可利用。因此,河流水环境容量已成为制约图们江地区开发的主要因素,为了确保     

Spatial-temporal Evolution of the Urban-rural Coordination Relationship in Northeast China in 1990–2018

To comprehensively understand the law of urban-rural relationship and propose scientific measures of urban-rural coordinated development in Northeast China, this study uses the coupling coordination degree model and geographically and temporally weighted regression(GTWR) model to analyze the spatial-temporal patterns and the corresponding driving mechanisms of its urban-rural coordination since 1990. The results are as follows. First, the urban-rural coupling coordination degree in Northeast Chi...     

钙同位素地球化学研究新进展及其在碳酸岩-共生硅酸盐研究中的应用

作为"非传统稳定同位素"家族成员,钙同位素正受到国际地学界日益广泛的关注。钙是主要的造岩元素,也是生物必需的元素。钙在地球各圈层广泛分布,研究钙同位素的地球化学行为将有助于提高我们对各种生物过程和地质过程的认识。钙同位素测定主要采用热电离质谱仪(TIMS)和多接收电感耦合等离子体质谱仪(MC-ICP-MS),分别表示为δ^44/40Ca和δ^44/42Ca。目前自然界可观测到的δ^44/40Ca变化范围为-2.0‰～6.75‰,约8.7‰。本文系统介绍了近年来钙同位素分析中样品溶解、化学分离、质谱测定以及高温地质过程中的钙同位素分馏及其地质应用等方面的研究成果,尤其对钙同位素在碳酸岩-共生硅酸盐岩研究中的意义、钙同位素组成以及取得的主要认识作了较为全面的介绍。阐述了放射成因⁴⁰Ca、部分熔融作用/分离结晶作用、地壳同化作用、古俯冲碳酸盐循环、热液蚀变作用、岩浆起源深度等对碳酸岩、硅酸盐岩的钙同位素组成造成的影响。最后,通过系统对比碳酸岩-共生硅酸盐岩的锂、镁、钙同位素研究成果,认为应该开展多元同位素体系的...