浙东沿海某地区大气干湿沉降对土壤重金属 元素含量的影响   总被引：7，自引：0，他引：7  

黄春雷  宋金秋  潘卫丰 《地质通报》2011,30(9):1434-1441

基于对浙东沿海某典型固废拆解区重金属元素大气干湿沉降特征的研究,探讨了重金属元素干湿沉降输入对土壤环境的影响。结果表明,研究区露天焚烧等不规范的固废拆解行为造成大气质量恶化,对土地质量造成严重的负面影响。区内干、湿沉降中Cd、Cu、Pb、Zn、Ni等重金属元素的含量均远高于浙江省干、湿沉降平均值和其它相关标准值,并且其年沉降通量在省内居高,尤其是Cu、Zn两种元素每年每平方百米沉降通量分别达7108g、11420g。研究显示,大气沉降能大大增加研究区土壤重金属元素的含量水平,Cu、Zn、Cd、Pb平均年增加量分别达3426ng/g、5819ng/g、6.50ng/g、582ng/g,并且年增加率较大,Pb、Cu、Zn等重金属元素的年增加率达0.5%以上。  相似文献   

Propagation of water waves over permeable rippled beds     

Ching-Jer Huang  Chih-Hsin Chen 《Ocean Engineering》2011,38(4):579-591

Unsteady two-dimensional Navier-Stokes equations and Navier-Stokes type model equations for porous flow were solved numerically to simulate the propagation of water waves over a permeable rippled bed. A boundary-fitted coordinate system was adopted to make the computational meshes consistent with the rippled bed. The accuracy of the numerical scheme was confirmed by comparing the numerical results concerning the spatial distribution of wave amplitudes over impermeable and permeable rippled beds with the analytical solutions. For periodic incident waves, the flow field over the wavy wall is discussed in terms of the steady Eulerian streaming velocity. The trajectories of the fluid particles that are initially located close to the ripples were also determined. One of the main results herein is that under the action of periodic water waves, fluid particles on an impermeable rippled bed initially moved back and forth around the ripple crest, with increasing vertical distance from the rippled wall. After one or two wave periods, they are then lifted towards the next ripple crest. All of the marked particles on a permeable rippled bed were shifted onshore with a much larger displacement than those on an impermeable bed. Finally, the flow fields and the particle motions close to impermeable and permeable beds induced by a solitary wave are elucidated.  相似文献   

Numerical simulation of wave-induced currents combined with parabolic mild-slope equation in curvilinear coordinates     

崔雷  佟飞飞  石峰 《中国海洋工程》2011,25(3):457-468

Researches on breaking-induced currents by waves are summarized firstly in this paper. Then, a combined numerical model in orthogonal curvilinear coordinates is presented to simulate wave-induced current in areas with curved boundary or irregular coastline. The proposed wave-induced current model includes a nearshore current module established through orthogonal curvilinear transformation form of shallow water equations and a wave module based on the curvilinear parabolic approximation wave equation. The wave module actually serves as the driving force to provide the current module with required radiation stresses. The Crank-Nicolson finite difference scheme and the alternating directions implicit method are used to solve the wave and current module, respectively. The established surf zone currents model is validated by two numerical experiments about longshore currents and rip currents in basins with rip channel and breakwater. The numerical results are compared with the measured data and published numerical results.  相似文献   

北京一次强对流天气过程的数值模拟     

王延东  周筠珺  孙战奇  杜克磊  苏科学 《成都信息工程学院学报》2011,(6):617-624

为了对发生于2008年07月04日北京的一次强对流天气有更多的认识,利用三维对流云模式对其进行数值模拟研究。结果表明：模式可以较好地模拟出强对流天气各主要宏观发展阶段的特征,以及云中水成物粒子转化的微观特征;模式能够很好地模拟出此次强对流天气过程的风场特征,对流系统中存在有利的环境条件,风暴是由气流的辐合上升引起的。在发展初期,对流云低层为辐合上升气流,在对流云发展的成熟阶段,近地面层以辐散气流为主,中上层以辐合气流为主,且辐合达到最大,之后随着云体的消散,低层辐散下沉气流加强。气流在顶端转变方向,形成辐散出流。  相似文献   

云南省2009/2010年秋冬季罕见干旱诊断分析   总被引：1，自引：0，他引：1  

黄慧君  李庆红  高月忠  钟爱华  陈红玉  李建美 《热带地理》2011,31(1)

利用气候诊断方法,对云南省2009/2010年秋冬季干旱的成因进行初步分析。结果表明:云南出现严重干旱与西太平洋副高、西风带环流等大气环流系统出现异常有直接关系。副高出现明显异常,较常年同期偏强、偏西,700hPa流场上孟加拉湾长时间为东北气流控制,不利于将暖湿气流输送到云南;2009/2010年秋冬北半球500hPa极涡偏于西半球,强度偏弱,不利于冷空气向云南输送,由于冷空气和暖湿气流的输送都受到阻碍,冷暖空气难以在云南上空交汇;云南上空为较干燥的气流控制、云南及孟加拉的OLR值偏高,对流活动受到抑制,降水云系偏少等是云南降雨异常偏少,高温干旱的重要原因。  相似文献   

Impact of the variation of westerly jets over East Asia on precipitation of eastern China in July     

LiNa Dong  PinWen Guo  PengXiang Wang  Li Qi 《寒旱区科学》2011,3(5):0408-0418

The impact of the northward jump and westward movement of the East Asian westerly jet core from the western Pacific Ocean to the Qinghai-Tibet Plateau on precipitation distribution of eastern China is studied. It is concluded that on the one hand, the northward jump of the jet causes the precipitation belt to move northward from the middle and lower reaches of the Yangtze River valley and withdraw during the Mei-yu season; on the other hand, the westward movement of the jet core has no correspondence with withdrawal of the Mei-yu season. However, the earlier or later occurrence of the westward movement of the jet has an influence on the process of the rain belt moving northward than the northward jump of the jet: the rain belt moves northward from the middle-lower Yangtze River valley to the Huaihe River and then to an area between the Yellow River and Huaihe River during years when the time of the westward movement of the jet core is later than that of the northward jump of the jet and from the middle-lower Yangtze River valley to an area between the Yellow River and Huaihe River in other years. Further analysis shows that: (1) The northward jump of the jet and the westward movement of the East Asian westerly jet core causes significant variation of the general atmospheric circulation in middle latitudes and water vapor transport from the western Pacific, but not from the Bay of Bengal. (2) Impact of the northward jump and the westward movement of the East Asian westerly jet core on circulation are different, therefore, water vapor transport from the western Pacific and its impact on the rain belt are different. The earlier or later occurrence of the westward movement of the jet core than the northward jump of the jet causes the process of circulation and water vapor transport to be different which produces a different process of the rain belt moving northward.  相似文献   

珠江流域碳酸盐岩与硅酸盐岩风化对大气CO_2汇的效应   总被引：6，自引：0，他引：6  

覃小群  蒋忠诚  张连凯  黄奇波  刘朋雨 《地质通报》2015,34(9):1749-1757

对珠江流域11个测站的河水1个水文年4次取样进行水化学和同位素测试分析,揭示无论是碳酸盐岩区还是硅酸盐岩区,岩石风化均使河流的离子成分以HCO3-、Ca2+、Mg2+为主,碳酸盐岩风化溶蚀速率和由碳酸盐岩风化溶蚀引起的大气CO2消耗量分别为27.60 mm/ka和540.21x103mol/(km2·a-1),是硅酸盐岩风化速率和由硅酸盐岩风化引起的大气CO2消耗量的10.8倍和6.7倍,说明碳酸盐岩风化是流域碳汇过程及效应的主体。由于有利的水热条件和高的碳酸盐岩面积比例,珠江流域平均岩石风化速率和由岩石风化作用引起的大气CO2消耗量分别为30.15mm/ka和620.36×103mol/(km2·a-1),为全球60条河流平均值的2.6倍。  相似文献   

大气环境变化的泥炭地质档案   总被引：2，自引：0，他引：2       下载免费PDF全文

鲍锟山  赵红梅  于晓菲  吕宪国  王国平 《地质论评》2011,57(2):234-242

雨养泥炭沼泽是一种重要的泥炭沼泽类型,具有全球广泛分布的特点,其养分补给主要源于大气降水(包括雨、雪和空气尘埃).它是一个记录大气环境变化的积极的信息储备系统,记录有大气输入的海盐气溶胶、沙尘颗粒、酸沉降、重金属和有机污染物等信息.采用地质定年技术将泥炭深度剖面转化到年代坐标上,并结合泥炭生物地球化学指标检测分析,提取...  相似文献   

拉萨市夏季大气降尘单颗粒矿物组成及其形貌特征   总被引：3，自引：0，他引：3       下载免费PDF全文

张学磊  邬光剑  岳雅慧  张成龙 《岩石矿物学杂志》2011,30(1):127-134

应用带能谱的电子扫描电镜(SEM-EDX)对拉萨市夏季正常天气下收集的大气自然沉降气溶胶样品进行分析,研究了拉萨市大气降尘矿物组成和各种物相形貌特征信息。拉萨市大气颗粒物含有硅酸盐颗粒、富钙颗粒、富铁颗粒、富碳颗粒(燃煤飞灰颗粒和燃油飞灰颗粒)和植物残体颗粒。根据颗粒物数量统计发现拉萨市大气颗粒物以硅酸盐颗粒为主,富钙颗粒和富铁颗粒次之,需要指出的是以燃油飞灰为主的富碳颗粒已占到一定比重,说明以燃油为主的机动车尾气对拉萨大气污染在加强。研究结果表明,大气降尘矿物成分及其形貌特征可以用作判定污染物来源的重要标志,拉萨大气中颗粒来源的多样性决定了治理措施也应综合进行。  相似文献   

ENSO事件对云南及临近地区春末初夏降水的影响   总被引：3，自引：0，他引：3       下载免费PDF全文

杨亚力  杜岩  陈海山 《大气科学》2011,35(4):729-738

本文采用合成及相关分析的方法,应用55年中国降水资料、美国NOAA海表温度资料以及NCEP/NCAR再分析资料,研究了ENSO事件对我国云南及其邻近地区春末初夏降水的影响及物理机理.研究结果表明:(1)在El Ni(n)o (La Ni(n)a)年,云南大部分地区4～5月降水偏少(多),东部地区相关信号尤其明显;(2)...  相似文献