近50年三江源地表湿润指数变化特征及其影响因素

基于三江源区1959—2008年月平均气温、最高气温、最低气温、相对湿度、降水量、风速和日照百分率等气候要素资料,应用修订的Penman-Monteith（P-M）模型计算了最大潜在蒸散量和地表湿润指数,分析其空间分布、年际和年代际变化特征及其主要气象因子的影响。结果表明：1959—2008年间,研究区年降水量呈增加趋势,降水量变化曲线线性拟合倾向率为5.316~13.047 mm.（10a）-1,春夏季增幅较大;最大潜在蒸散量呈增加趋势,年最大潜在蒸散量变化曲线线性拟合倾向率在5.073~10.712 mm.（10a）-1,夏季增幅最大;地表湿润指数变化也呈增加趋势,年地表湿润指数变化曲线线性拟合倾向率0.011~0.026（10a）-1,冬季增幅最大,在15年周期附近,出现了3~5个干湿交替期,1984年之后为偏湿期,在中高频区,1998—2006年有偏干振荡;影响三江源区地表湿润指数的主要因子是降水量、相对湿度和平均最高气温。     

汶川地震地表变形特征

汶川地震地表变形特征丰富多彩。在震后40天自北至南对地震地表变形现象进行了为期10天的专题考察和分析,对北川、擂鼓、汉旺、蓥华、白鹿、小鱼洞、虹口和映秀等8个断裂出露部位进行了重点剖析。结果表明,不同侧面,不同级次的现象均显示出统一的变形变位图案,但具体而言它们比理论模型、规例要复杂得多。它们具体表现为:沿汶川地震断裂面推挤形成隆起,产生纵向、横向裂隙;推挤前缘冲断塌落,形成逆断型崩积楔;多方向挤压、或引张,显示同一应力作用下变形组合的复杂性。这些均不同程度地丰富了现有的应力作用理论。     

VOC emission caps constrained by air quality targets based on response surface model: A case study in the Pearl River Delta Region, China

Because of the recent growth in ground-level ozone and increased emission of volatile organic compounds (VOCs), VOC emission control has become a major concern in China. In response, emission caps to control VOC have been stipulated in recent policies, but few of them were constrained by the co-control target of PM_2.5 and ozone, and discussed the factor that influence the emission cap formulation. Herein, we proposed a framework for quantification of VOC emission caps constrained by targets for PM_2.5 and ozone via a new response surface modeling (RSM) technique, achieving 50% computational cost savings of the quantification. In the Pearl River Delta (PRD) region, the VOC emission caps constrained by air quality targets varied greatly with the NO_x emission reduction level. If control measures in the surrounding areas of the PRD region were not considered, there could be two feasible strategies for VOC emission caps to meet air quality targets (160 µg/m³ for the maximum 8-hr-average 90th-percentile (MDA8-90%) ozone and 25 µg/m³ for the annual average of PM_2.5): a moderate VOC emission cap with <20% NOx emission reductions or a notable VOC emission cap with >60% NO_x emission reductions. If the ozone concentration target were reduced to 155 µg/m³, deep NO_x emission reductions is the only feasible ozone control measure in PRD. Optimization of seasonal VOC emission caps based on the Monte Carlo simulation could allow us to gain higher ozone benefits or greater VOC emission reductions. If VOC emissions were further reduced in autumn, MDA8-90% ozone could be lowered by 0.3-1.5 µg/m³, equaling the ozone benefits of 10% VOC emission reduction measures. The method for VOC emission cap quantification and optimization proposed in this study could provide scientific guidance for coordinated control of regional PM_2.5 and O₃ pollution in China.     

典型舰船用金属材料腐蚀与防护研究进展

针对舰船用金属材料在复杂海洋环境下存在的腐蚀问题,概述了舰船用金属材料腐蚀与防护的相关研究进展。介绍了合金钢、铜合金、钛合金和铝合金这些典型舰船用金属材料的常用类型和使用场所,阐述了舰船用金属材料所处不同海洋区带内的腐蚀环境特征,以及点蚀、缝隙腐蚀、电偶腐蚀、微生物腐蚀和应力腐蚀开裂等舰船用金属材料常发生的腐蚀类型。综述了目前对舰船用金属材料腐蚀防护采取的措施,重点关注了表面涂镀层和改性技术的研究进展。最后,提出了舰船用金属材料腐蚀防护未来的研究方向,需从加强腐蚀机理研究、建立腐蚀数据库和发展新型表面腐蚀防护技术3方面入手。     

纳米金增强SPR铅离子检测器构建

为满足采用简便方法检测痕量铅离子（Pb²⁺）的需求,构建了新型的超灵敏、高特异性表面等离子体共振（SPR）生物传感器,用于水中Pb²⁺检测.以硫醇化GR-5脱氧核酶（DNAzyme）为Pb²⁺特异性识别探针,并自组装到芯片金膜表面,底物官能化的纳米金（S-AuNPs）用于信号增强,并与DNAzyme杂交形成传感薄膜.AuNPs不仅增加了质量变化,其局部表面等离子体共振（LSPR）与芯片表面传播SPR的耦合作用也可产生信号放大的效果.在Pb²⁺离子存在下,DNAzyme催化底物裂解,导致AuNPs的去除并引起SPR信号显著变化.通过X射线光电子能谱和扫描电镜对芯片表面的表征分析验证了传感薄膜构建过程和检测原理.Pb²⁺检测实验结果表明,1 μmol/L DNAzyme修饰的传感器检测效果最好,检测限为80pmol/L,并在100nmol/L范围内与Pb²⁺浓度的对数呈线性关系（R²=0.992）.该传感器对10倍浓度的其他金属离子无明显响应,说明其具有良好的Pb²⁺特异性;检测自来水和地下水中Pb²⁺的结果与ICP-MS方法有良好的一致性.研究建立的Pb²⁺检测方法具有高灵敏度和特异性,且操作简便,具有现场检测的应用前景.     

Effects of Climate and Land Cover on Hydrology in the Southeastern U.S.: Potential Impacts on Watershed Planning

The hydrologic response to statistically downscaled general circulation model simulations of daily surface climate and land cover through 2099 was assessed for the Apalachicola‐Chattahoochee‐Flint River Basin located in the southeastern United States. Projections of climate, urbanization, vegetation, and surface‐depression storage capacity were used as inputs to the Precipitation‐Runoff Modeling System to simulate projected impacts on hydrologic response. Surface runoff substantially increased when land cover change was applied. However, once the surface depression storage was added to mitigate the land cover change and increases of surface runoff (due to urbanization), the groundwater flow component then increased. For hydrologic studies that include projections of land cover change (urbanization in particular), any analysis of runoff beyond the change in total runoff should include effects of stormwater management practices as these features affect flow timing and magnitude and may be useful in mitigating land cover change impacts on streamflow. Potential changes in water availability and how biota may respond to changes in flow regime in response to climate and land cover change may prove challenging for managers attempting to balance the needs of future development and the environment. However, these models are still useful for assessing the relative impacts of climate and land cover change and for evaluating tradeoffs when managing to mitigate different stressors.     

大鹏湾表层沉积物中碳、氮、磷的多年调查结果和有机质来源分析

依据1998—2006年18个航次13个站的调查资料,简要描述和分析了大鹏湾表层沉积物中包括碳、氮、磷的多项生物地球化学要素多年的平均空间分布和年际变化,并依据TOC/TN原子比探讨沉积物中有机质的来源.结果表明,大鹏湾的水动力条件对沉积物中各生物地球化学要素的分布变化影响不大,TOC、TN和TP含量分别为(17600±4600) mg·kg^-1、(1738±446) mg·kg^-1和(562±89) mg·kg^-1,比珠江口和大亚湾高.9年调查期间,TOC、TC、TN和TP含量的年际变化趋势都是上升的,表明随着周边地区经济的迅速发展和人口的不断增加,产生的大量有机质通过小河流和地表径流排放入海,使大鹏湾中沉积物的环境逐渐恶化.TOC/TN原子比为12.4±2.5,介于海洋浮游生物源和陆生高等植物源之间,反映了大鹏湾表层沉积物中有机质是陆源和水生2种来源的混合输入.TOC/TN原子比呈逐年上升趋势,表明大鹏湾接受陆源有机质与水生有机质的比例逐渐增加.     

RELATION OF NITRATE CONCENTRATIONS TO BASEFLOW IN THE RACCOON RIVER,IOWA1

ABSTRACT: Excessive nitrate‐nitrogen (nitrate) export from the Raccoon River in west central Iowa is an environmental concern to downstream receptors. The 1972 to 2000 record of daily streamflow and the results from 981 nitrate measurements were examined to describe the relation of nitrate to streamflow in the Raccoon River. No long term trends in streamflow and nitrate concentrations were noted in the 28‐year record. Strong seasonal patterns were evident in nitrate concentrations, with higher concentrations occurring in spring and fall. Nitrate concentrations were linearly related to streamflow at daily, monthly, seasonal, and annual time scales. At all time scales evaluated, the relation was improved when baseflow was used as the discharge variable instead of total streamflow. Nitrate concentrations were found to be highly stratified according to flow, but there was little relation of nitrate to streamflow within each flow range. Simple linear regression models developed to predict monthly mean nitrate concentrations explained as much as 76 percent of the variability in the monthly nitrate concentration data for 2001. Extrapolation of current nitrate baseflow relations to historical conditions in the Raccoon River revealed that increasing baseflow over the 20th century could account for a measurable increase in nitrate concentrations.     

Distribution characteristics of dinoflagellate cysts in the Yantian Port,Shenzhen, China北大核心CSCD

An annual quarterly survey of six stations in Yantian Port, Shenzhen, China was conducted from January 2020 to October 2020 to investigate the spatial and temporal distribution of dinoflagellate cysts in the surface sediment of Yantian Port. In total, 36 species representing five groups and two uncertain taxa were identified. The dominant species were Scrippsiella trochoidea, Alexandrium spp., Gymnodinium catenatum, Cochlodinium spp., and Lingulodinium polyedrum. The seasonal difference was not obvious in terms of temporal distribution. The number of species ranged from 32 to 36, and the abundance varied from 297 to 996 cysts/g. The annual average values of the diversity index, richness index, and evenness index were 3.65, 1.55, and 0.93, respectively. The annual number and abundance of heterotrophic species were higher than those of autotrophic species. The number and abundance of species at stations near the dock zone were lower than those near the adjacent area. Notably, six toxic dinoflagellate cysts were found in the surface sediment of Yantian Port, indicating a potential outbreak risk for their vegetative cells in the local coastal area. This study provides a picture of the “Seed Bank” of dinoflagellates near Yantian Port, Shenzhen, and provides a reference value for predicting the occurrence of algal blooms. © 2022 Science Press. All rights reserved.     

海州露天矿采空区地表CO2通量的试验研究

为探究海州露天矿东邦废弃采空区自然发火状态,基于采空区遗煤自燃特性和气体扩散理论,采用智能土壤气体通量监测系统,以月为单位,对东邦自燃采空区上覆地表CO₂通量开展长周期、多测点连续性监测试验;根据试验区域内地表CO₂通量和土壤温度分布特征,探究地下火区释放CO₂的地表涌出范围和变化情况;同时,着眼于温室气体排放的评估,计算试验区域内的CO₂涌出量,并分析其随时间的变化特征。结果表明:地表CO₂通量与土壤温度有明显正相关性;试验区域地表CO₂高通量区域呈逐月扩大和递增的趋势;CO₂涌出量随月份逐渐递增,试验区域年CO₂涌出量约为3.6×10⁶ m³。