The Amazon river breeze and the local boundary layer: I. Observations     

Amauri Pereira de Oliveira  David R. Fitzjarrald 《Boundary-Layer Meteorology》1993,63(1-2):141-162

Observations of the diurnal evolution of the planetary boundary layer over the Amazon rain forest, made at sites close to the confluence of the Solimões and Negro rivers (approximately at 3°S, 60°W) near Manaus, Amazonas, Brazil, show the existence of a diurnal rotation of the wind near the surface and the frequent presence of low-level nocturnal wind maxima. These circulations are shown to be plausibly explained as elements of a river and land breeze circulation induced by the thermal contrast between the rivers and the adjacent forest.  相似文献   

Seasonal soil water storage changes beneath central Amazonian rainforest and pasture     

M. G. Hodnett  L. Pimentel da Silva  H. R. da Rocha  R. Cruz Senna 《Journal of Hydrology》1995,170(1-4):233-254

Evaporation and infiltration were compared for tropical rainforest and pasture, near to Manaus, Brazil from October 1990 to February 1992 using measurements of soil water storage over a depth of 2 m. The soil is a clayey oxisol of low water available capacity. In both of the dry seasons studied, the maximum change in soil water storage in the forest was 154 mm and in the pasture it was 131 and 112 mm. Similar behaviour of the soil water reservoir below forest and pasture in the wet season implied that differences in evaporation and drainage were small. In the dry season, soil water storage behaviour in the upper metre of the soil was similar but there were marked differences in the second metre. The pasture took up little water from below 1.5 m but the forest appeared to utilise all of the available water in the 2 m profile in both seasons.

The water balance of the 2 m profile showed that the pasture evaporation rate was equal to that of the forest until storage had decreased 80 mm from the maximum. There was then a decline in pasture evaporation rate to 1.2 mm day⁻¹ as the storage decreased by a further 50 mm. In contrast, the forest uptake rate remained above 3.5 mm day⁻¹ until storage had decreased 140 mm from the maximum (within 15 mm of the extraction limit), before declining abruptly to less than 1.5 mm day⁻¹. There was strong evidence that the forest was able to abstract water from depths greater than 3.6 m.

Spatial variability of soil water storage was significantly greater beneath the pasture than beneath the forest, particularly following rainfall events in the dry season. This was largely the result of redistribution of rainfall as local surface runoff. There was no evidence of redistribution or runoff in the forest.  相似文献   

Aquifer development planning to supply a seaside resort: a case study in Goa,India     

J. P. Cárcomo Lobo Ferreira  Maria da Conceição Cunha  A. G. Chachadi  Kai Nagel  Catarina Diamantino  Manuel Mendes Oliveira 《Hydrogeology Journal》2007,15(6):1147-1155

Using the hydrogeological and socio-economic data derived from a European Commission research project on the measurement, monitoring and sustainability of the coastal environment, two optimization models have been applied to satisfy the future water resources needs of the coastal zone of Bardez in Goa, India. The number of tourists visiting Goa since the 1970s has risen considerably, and roughly a third of them go to Bardez taluka, prompting growth in the tourist-related infrastructure in the region. The optimization models are non-linear mixed integer models that have been solved using GAMS/DICOPT++ commercial software. Optimization models were used, firstly, to indicate the most suitable zones for building seaside resorts and wells to supply the tourist industry with an adequate amount of water, and secondly, to indicate the best location for wells to adequately supply pre-existing hotels. The models presented will help to define the optimal locations for the wells and the hydraulic infrastructures needed to satisfy demand at minimum cost, taking into account environmental constraints such as the risk of saline intrusion.

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Résumé A l’aide de données hydrogéologiques et socio-économiques, dérivées d’un projet de recherche de la Commission Européenne sur l’étude, la surveillance et la durabilité de l’environnement c?tier, deux modèles d’optimisation ont été appliqués en vue de satisfaire les besoins futurs en ressources en eau de la zone c?tière de Bardez au Goa en Inde. Le nombre de touristes qui visitent le Goa depuis les années 70 a considérablement augmenté et environ un tiers d’entre eux se rend à Bardez taluka, ce qui encourage la croissance des infrastructures liées au tourisme dans la région. Les modèles d’optimisation sont des modèles non linéaires mixtes en nombres entiers qui ont été résolus en utilisant le logiciel commercial GAMS/DICOPT++. Les modèles d’optimisation ont été utilisés pour indiquer premièrement les zones les plus appropriées pour construire des stations balnéaires et des puits pour approvisionner en quantité d’eau suffisante l’industrie touristique, et deuxièmement pour indiquer la meilleure localisation de puits pour l’alimentation des h?tels préexistants. Les modèles présentés aideront à définir les localisations optimales des puits et des infrastructures hydrauliques nécessaires à la satisfaction de la demande à un co?t minimum, tout en prenant en compte les contraintes environnementales, tel que le risque d’intrusion saline.

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Resumen Se han aplicado dos modelos de optimización en base a datos socio-económicos e hidrogeológicos derivados de un proyecto de investigación de la Comisión Europea sobre medición, monitoreo y sostenibilidad del ambiente costero para satisfacer las necesidades futuras de recursos hídricos de la zona costera de Bardez en Goa, India. El número de turistas que visita Goa desde la década de 1970′s ha subido considerablemente y cerca de un tercio de ellos van a Bardez taluka impulsando el crecimiento en la infraestructura turística de la región. Los modelos de optimización son modelos de números enteros mixtos no-lineales que se han resuelto usando el programa comercial GAMS/DICOPT++. Los modelos de optimización se usaron, primero para indicar las zonas más adecuadas para la construcción de centros de diversión en las márgenes del océano y pozos para abastecer la industria turística con una adecuada cantidad de agua, y segundo, para indicar la mejor localización de pozos para el abastecimiento de hoteles pre-existentes. Los modelos que se presentan ayudarán a definir las localizaciones óptimas para los pozos y las infraestructuras hidráulicas necesarias para satisfacer la demanda al mínimo costo, tomando en consideración restricciones ambientales tal como el riesgo de intrusión salina.

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Scalar advection schemes for ocean modelling on unstructured triangular grids     

William Paul Budgell  Anabela Oliveira  Morten D. Skogen 《Ocean Dynamics》2007,57(4-5):339-361

Several schemes for scalar advection on unstructured triangular grids are assessed for possible use in ocean modelling applications. Finite element, finite volume and finite volume–element approaches are evaluated. A series of tests, including a numerical order of convergence analysis, idealized rotating cone and cylinder experiments, and transport of a tracer through the Stommel Gyre representation of ocean basin-scale circulation, are carried out. Volume element Eulerian–Lagrangian and third-order Runge-Kutta discontinuous Galerkin schemes are recommended for use in tracer studies. Taylor–Galerkin and second-order Runge–Kutta discontinuous Galerkin are found to be robust and accurate second-order schemes. When positivity is required, a fluctuation redistribution scheme was found to be an easily implemented, accurate, and computationally efficient approach. Responsible editor: Phil Dyke  相似文献   

偏高岭石水热转化法合成NaA分子筛反应机理研究     

李益  胡大千 《世界地质》2002,21(3):258-262

在偏高岭石水热转化法合成NaA型沸石分子筛体系中，通过对反应不同时间内的固相产物的XRD－FT－IR图谱分析，以及对SEM形貌变化的观察，认为晶化过程包括异相成核和均相成核两个过程，其中异相成核先于均相成核，但是它们之间没有明显界限，只是取决于偏高岭石的表面溶解程度，偏高岭石不仅提供了反应所需的化学组分，而且也为晶核形成提供了必要的界面条件。  相似文献   

甚低频电磁法在某萤石矿勘查中的应用   总被引：6，自引：0，他引：6  

白大明  关继东  苏来柱 《物探与化探》2002,26(1):39-41

内蒙古海力敏萤石矿属热液脉型,萤石—石英矿受花岗岩体内NW向断裂破碎带控制。矿区开展了甚低频电磁法找矿勘查研究,在已知矿体上测得明显的甚低频电磁异常,证实了该方法对寻找此类萤石矿床的有效性。在不易识别开采的掩盖区,所测甚低频电磁异常显示控矿断裂带仍存在,极可能赋存萤石矿体。  相似文献   

相位激电法(偶极-偶极)单频电磁耦合校正方法   总被引：2，自引：2，他引：2  

王书民  雷达 《物探与化探》2002,26(1):57-59,63

主要介绍一种相位激电法(偶极—偶极,以下简称偶极)电磁耦合校正方法,其原理是将视电阻率近似视为均匀大地电阻率,利用均匀大地条件下偶极装置电磁感应响应的正演计算方法,算出电磁感应响应,再将其从观测的总响应中去除,从而达到电磁耦合校正的目的。  相似文献   

对山西应县木塔采用纳米复合纤维加固的建议   总被引：9，自引：0，他引：9  

李大华  徐扬  郑鹄 《山西地震》2001,(4):24-25

山西应县木塔是古人留给我们的稀世珍宝，如何妥善地保护好这一珍贵的遗产，使之在加固时尽量保持原有的风貌，是一项复杂而艰巨的任务。根据长期的研究成果和实际工作的经验，提出了用纳米复合纤维加固应县木塔的建议，介绍了纳米复合纤维材料的特点，分析讨论了加固时的一些具体技术问题。  相似文献   

三角洲感潮河段洪潮水位频率分析方法的初步研究   总被引：3，自引：0，他引：3  

陈俊鸿  黄大基  吴赤蓬  许扬生  宋军  梁国昭 《热带地理》2001,21(4):342-345

根据珠江三角洲感潮河段年最高洪潮水位存在长期上升趋势的事实，提出了河口区感潮河段洪潮水位频率分析一种新的计算方法，新方法的分析结果表明，未来不同年代同频率的设计洪潮水位各不相同，也存在相应的长期变化趋势。以灯笼山站为例，新方法计算的2030年和2050年的百年一遇设计洪潮水位分别为3.12m和3.28m，比传统频率分析方法计算的结果分别高出0.24m和0.40m。建立有关部门在制定河口区的防洪标准时，根据洪潮水位的长期变化趋势作相应的动态调整，以适应河口区洪潮水位变化的实际情况。  相似文献   

中国西北地区季节性积雪的性质与结构   总被引：17，自引：2，他引：17  

魏文寿  秦大河  刘明哲 《干旱区地理》2001,24(4):310-313

中国内陆地区积雪分布十分广泛。根据西北地区大陆性气候条件下形成的“干寒型”积雪的特征 ,对中国天山和阿尔泰山山区的季节性积雪进行了观测与分析。结果表明 ,该区最大积雪深度达 15 2cm(1997) ,积雪层一般由新雪 (或表层凝结霜 )、细粒雪、中粒雪、粗粒雪、松散深霜、聚合深霜层和薄融冻冰层组成。与“湿暖型”积雪相比 ,“干寒型”积雪的性质具有密度小 (新雪的最小密度为 0 .0 4 g/cm3 )、含水率少 (隆冬期 <1% )、温度梯度大(最大可达 - 0 .5 2℃ /cm)、深霜发育层厚等特点 ,并且变质作用以热量交换和雪层压力变质作用为主。据中国科学院天山积雪与雪崩研究站 (43°2 0N ,84°2 9E ,海拔 1776m)的观测资料 ,中国内陆干旱区冬季积雪期雪面太阳辐射通量以负平衡为主 ,新雪雪面反射率达 96 % ,短波辐射在干寒型积雪中的穿透厚度达 2 8cm。春季积雪消融期 ,深霜层厚度可占整个积雪层厚度的 80 %。随着气温的升高 ,雪粒间的键链首先融化 ,使积雪变得松散 ,内聚力、抗压、抗拉和抗剪强度降低 ,积雪含水率也随之增大 ,整个积雪层趋于接近 0℃的等温现象 ,因此 ,春季天山、阿尔泰山等山地全层性湿雪崩频繁发生  相似文献