佛山西樵山及邻近地区MIS5a红土中主量元素含量特征及其古气候意义     

牛东风  李保生  舒培仙  王丰年  琚琛琪  李志文  温小浩  司月君  郭亿华  王晨 《地质论评》2019,65(5):1217-1228

本文主要对广东佛山西樵和邻近的粤东北的临江地层剖面MIS5a网纹红土的主量元素含量进行了研究。结果表明,这两个剖面MIS5a红土的SiO 2 、Al 2 O 3 、TOFE（Fe 2 O 3 +FeO）含量、硅铝率n (SiO2) / n (Al2O3) 和化学蚀变指数 CIA 值与我国中亚热带和南亚热带红土都有明显的差异,而与热带地区——海南岛和雷州半岛红土中相应的地球化学指标比较接近。此前,在研究区碧寿洞和罗沙岩洞穴发现的MIS5a大熊猫—剑齿象动物化石群中,都含有热带动物成员——长臂猿（ Hylobates sp.）、犀（ Rhinoceros sp.）、中国犀（ Rhinoceros sinensis ）、华南巨獏（ Megatapirus cf. angustus ）和亚洲象（ Elephas sp.）。据此提出,西樵山和邻近地区MIS5a网纹红土代表了热带气候环境;MIS5a期间南岭以南广东境内的生物气候带属于边缘热带范围。  相似文献   

基于主体功能区划的广州市土地资源安全评价   总被引：9，自引：3，他引：6  

郑荣宝  刘毅华  董玉祥  朱高儒 《地理学报》2009,64(6):654-664

以科学发展观为依据,采用三维魔方图分类法对广州市进行主体功能区划,划分为禁止开发区、限制开发区、重点开发区、优化开发区和土地储备区.在此基础上以30m×30m的栅格作为最小的评价单元,从土地资源数量安全、质量安全、经济安全和生态安全四方面构建土地资源安全评价指标体系,并利用改进的支持向量机模型(SVM)进行评价与分类.结果表明:①广州市主体功能区划具有明显的方向性,其中禁止开发区占总面积的37.21%,限制开发区占24.90%,重点开发区占19.60%,优化开发区占13.31%,土地储备区占4.98%;②土地资源安全分值介于16～82之间,不同行政区土地资源安全状况具有明显差异,土地安全分较高的主要有南沙区和花都区,而荔湾区土地安全分最低:③广州市土地资源安全形势不容乐观,危险区和较不安全区占评价面积的比例达32.35%,主要分布在增城市和从化市的偏远山区以及市中心的荔湾区及越秀区.单位建设用地GDP、人均居住面积和归一化植被指数是其主要警源因素.  相似文献   

厦门浔江湾水体交换的~(224)Ra和~2H示踪研究     

蔡明刚  陈敏  蔡毅华  高众勇  邱雨生  黄奕普 《台湾海峡》2000,(2)

本文研究了 980 32 6航次厦门浔江湾海水中2 2 4Ra和2 H的含量与分布 ,揭示其水体交换特征。表层水体中2 2 4Ra的放射性比度介于 4.94～ 1 3.70Bq/m3之间 ,平均值为 7.2 6Bq/m3 ;δD测值介于 - 8.9× 1 0 -3 ～ - 5 .7× 1 0 -3 之间 ,平均值为 - 7.3× 1 0 -3 。表层水2 2 4Ra和2 H的分布表明 ,浔江湾在一定程度上受到西港水的入侵 ,湾内外水体的不完全交换造成外海水在该湾中部的滞留。  相似文献   

Dissipative Travelling Wave Solution for EI Ni(n)o Tropic Sea-air Coupled Oscillator     

WEN Zhaohui  LIN Wantao  LIN Yihua  MO Jiaqi 《中国地理科学(英文版)》2010,20(3)

El Ni(n)o and Southern Oscillation(ENSO)is an interannual phenomenon involved in the tropical Pacific sea-air interactions.An asymptotic method of solving equations for the ENSO model is proposed.Based on a class of oscillator of ENSO model and by employing a simple and valid method of the variational iteration,the coupled system for a sea-air oscillator model of interdecadal climate fluctuations is studied.Firstly,by introducing a set of functionals and computing the variationals,the Lagrange multipliers are obtained.And then,the generalized variational iteration expressions are constructed.Finally,by selecting appropriate initial iteration,and from the iterations expressions,the approximations of solution for the sea-air oscillator ENSO model are solved successively.The approximate dissipative travelling wave solution of equations for corresponding ENSO model is studied.It is proved from the results that the method of the variational iteration can be used for analyzing the sea surface temperature anomaly in the equatorial Pa-cific of the sea-air oscillator for ENSO model.  相似文献   

粤港澳大湾区科技创新潜力的微观集聚格局及其空间规划应对   总被引：1，自引：0，他引：1  

邱坚坚  刘毅华  袁利  陈澄静  黄清瑶 《热带地理》2020,40(5):808-820

创新活动发生在具体地点上,其空间黏性已有广泛关注,但当前研究却未能深入微观尺度的创新空间集聚,难以精细化识别创新潜力。文章结合知识、技术、环境三维创新的角度搭建基于兴趣点（POI）微观数据的科技创新潜力空间指标体系,所得结果与粤港澳大湾区都市发展现状高度一致。同时发现：1）科技创新潜力的空间集聚显著,其中知识创新向核集聚,技术创新呈轴带式外溢,但创新环境存在较大协同缺失;2）热点分布呈现出点群集聚、组团联动、多中心并存等特征,形成智慧科研型、产业科技型、环境孵化型、综合发展型等16个创新集聚区,受到“亲水性”布局与传统行政力量的重要影响;3）微观视域下同时体现了空间上的功能性分异及较强的边界模糊效应,广－莞－深－港创新廊道基本成型,不过区域多层次非均衡分布与创新深度融合仍需改善。根据研究结果,需要进一步加大创新的环境营造与三维融合,增强重要创新节点的辐射,明确创新产业差异化定位,深化创新活动的无界互动融通,从而推动湾区创新协同发展。  相似文献   

Perturbed solution of sea-air oscillator for the El Nino/ La Nina-Southern Oscillation mechanism     

ZHOU Xianchun    LIN Yihua  WANG Hui  MO Jiaqi  College of Electronic  Information Engineering  Nanjing University of information Science  Technology  Nanjing  China Division of Computational Science  E-Institutes of Shanghai Universities  at SJTU  Shanghai    China State Key Laboratory of Numerical Modeling for Atmospheric Sciences  Geophysical Fluid Dynamics 《海洋学报(英文版)》2009,(3)

A class of coupled system of the El Nino/La Nina-Southern Oscillation (ENSO) mechanism is studied. Using the perturbed theory, the asymptotic expansions of the solution for ENSO model are obtained and the asymptotic behavior of solution for corresponding problem is considered.  相似文献   

渤海湾现代沉积速率和沉积过程   总被引：13，自引：0，他引：13  

杜瑞芝  刘国贤 《海洋地质与第四纪地质》1990,10(3):15-22

本文报道了笔者于渤海湾采集的9个柱样品,用~(210)Pb法测定的现代沉积速率;~(210)Pb剖面揭示出人类和自然原因所产生的沉积事件。并对该湾的沉积过程进行了探讨。 海河口844站~(210)Pb剖面反映出六十年代初,天津新港进行水下工程时出现瞬时堆积的记录;1041站记录了1964年一次雍潮出现的高速沉积带。从而,表明人类和自然对现代沉积作用的贡献,并且,指出这对海洋工程、沉积学及环境科学研究均十分重要。  相似文献   

台湾海峡铀的来源及保守性混合     

岑蓉蓉  刘艳娜  邢娜  陈敏  成华  蔡毅华 《海洋学报(英文版)》2017,36(3):72-81

Seawater samples are collected in the spring of 2013 from the Taiwan Strait for the analysis of uranium(U)concentrations and isotopic compositions using MC-ICP-MS, and the geochemical behavior patterns of U in the Taiwan Strait are then investigated. Average concentrations of individual U isotopes are(3.23±0.14) μg/kg for 238 U,(2.34±0.09)×10~(–2) μg/kg for ~(235)U and(2.05±0.07)×10~(–4) μg/kg for 234 U. Correspondingly, the U isotopic compositions are 155±18 for δ234U and 138±2 for 238U:235U. The U concentrations and isotopic ratios in the Taiwan Strait are similar to those of open ocean seawater, suggesting the dominance of the open ocean input to the strait's U pool.However, river input, as suggested by the slightly lower salinity than that of the open ocean, also affected the U concentrations and isotopic compositions in the strait. From a compilation of U concentrations in the Taiwan Strait and adjacent areas, including the Jiulong Estuary and Zhujiang Estuary, the Xiamen Bay and the northern South China Sea, a strong and significant relationship between U concentration and salinity [U:S; U=(0.093 4±0.002 4)S+(0.092 0±0.061 5)] is revealed, suggesting conservative mixing of U in the Taiwan Strait. To better understand the U geochemistry in the Taiwan Strait, a multiple endmembers mixing model is applied to estimate the contributions of potential sources. The open ocean seawater contributed 69%–95% of U in the Taiwan Strait, with river water approximately 2%, and dust deposition only around 0.13%. Therefore, the model results supported the open ocean input source and the conservative mixing behavior of U derived from the observation of U concentrations and isotopic ratios and U:S ratios. The sediment interstitial water may be an important source of U to the Taiwan Strait with a possible contribution of 3%–29%, consistent with previous investigations based on radium isotopes.However, further investigations are warranted to examine the U concentration in the sediment interstitial water and its input to the overlying seawater in the Taiwan Strait.  相似文献   

Approximate solution for mechanism of thermally and wind-driven ocean circulation     

Jiaqi Mo  Wantao Lin  Yihua Lin 《中国地理科学(英文版)》2010,20(5):383-388

The thermally and wind-driven ocean circulation is a complicated natural phenomenon in the atmospheric physics. Hence we need to reduce it using basic models and solve the models using approximate methods. A non-linear model of the thermally and wind-driven ocean circulation is used in this paper. The results show that the zero solution of the linear equation is a stable focus point, which is the path curve trend origin point as time (t) trend to infinity. By using the homotopic mapping perturbation method,...  相似文献   

Floodplain effects on the transport of dissolved and colloidal trace elements in the East Pearl River,Mississippi          下载免费PDF全文

Moo Joon Shim  Yihua Cai  Laodong Guo  Alan M. Shiller 《水文研究》2017,31(5):1086-1099

Substantial work suggests that floodplain wetlands could play a role in modifying fluvial fluxes of dissolved and colloidal trace elements. Yet, few studies have directly addressed this issue. We examined trace elements in the East Pearl River (Mississippi or Louisiana, USA), which is surrounded by wetlands that are temporally more or less connected to the river depending on river stage. Dissolved and colloidal trace element samples, along with ancillary data, including dissolved organic carbon and nutrients, were collected during eight surveys of this system at different flow stages from November 2007 to September 2008. Hydrology of the system is complex due to seasonal changes in water sources as well as potential inputs from the floodplain wetlands and the hyporheic zone. We therefore considered effects including nonconservative mixing of water sources, saltwater intrusion, and floodplain wetland flux requirements needed to support observed downstream concentration changes. During moderately high discharge, fluxes of many elements (e.g., Cd, Fe, Mn, and Zn) increased downstream by 20% or more, with inputs from the floodplain wetlands as the apparent source. At the highest discharge, however, wetland inputs to the river may have been rate‐limited (i.e., the wetland source was flushed faster than biogeochemical processes could regenerate dissolved or colloidal material). At low discharge, other effects, including saltwater intrusion and hyporheic zone interactions, are important. Both redox processes and organic ligands (or dissolved organic carbon), along with the supply of wetland inputs (or removal) relative to river fluxes, appear to be key factors determining floodplain wetland effects. While the behavior of some elements suggests they were dominantly affected by redox processes (Mn and V) or by organic complexation (dissolved Fe and light rare earths), other elements were affected by more than one process in ways that remain obscure (Cu). Overall our results are broadly consistent with previous field, laboratory, and modeling studies and suggest that a better understanding of the sources and transformations of Fe is a key area for future research.  相似文献