Multi-source data fusion and modeling to assess and communicate complex flood dynamics to support decision-making for downstream areas of dams: The 2011 hurricane irene and schoharie creek floods,NY     

《International Journal of Applied Earth Observation and Geoinformation》2017

In light of climate and land use change, stakeholders around the world are interested in assessing historic and likely future flood dynamics and flood extents for decision-making in watersheds with dams as well as limited availability of stream gages and costly technical resources. This research evaluates an assessment and communication approach of combining GIS, hydraulic modeling based on latest remote sensing and topographic imagery by comparing the results to an actual flood event and available stream gages. On August 28th 2011, floods caused by Hurricane Irene swept through a large rural area in New York State, leaving thousands of people homeless, devastating towns and cities. Damage was widespread though the estimated and actual floods inundation and associated return period were still unclear since the flooding was artificially increased by flood water release due to fear of a dam break. This research uses the stream section right below the dam between two stream gages North Blenheim and Breakabeen along Schoharie Creek as a case study site to validate the approach. The data fusion approach uses a GIS, commonly available data sources, the hydraulic model HEC-RAS as well as airborne LiDAR data that were collected two days after the flood event (Aug 30, 2011). The aerial imagery of the airborne survey depicts a low flow event as well as the evidence of the record flood such as debris and other signs of damage to validate the hydrologic simulation results with the available stream gauges. Model results were also compared to the official Federal Emergency Management Agency (FEMA) flood scenarios to determine the actual flood return period of the event. The dynamic of the flood levels was then used to visualize the flood and the actual loss of the Old Blenheim Bridge using Google Sketchup. Integration of multi-source data, cross-validation and visualization provides new ways to utilize pre- and post-event remote sensing imagery and hydrologic models to better understand and communicate the complex spatial-temporal dynamics, return periods and potential/actual consequences to decision-makers and the local population.  相似文献   

海洋生态系统动力学浅说   总被引：4，自引：1，他引：4  

管玉平  林一骅 《地球科学进展》1997,12(5):447-450

讨论了海洋生态系统动力学的研究目的，任务和特点。阐述了它的基本理论问题，此外，协同性，可预报性，突变性以及稳定性是人们关切的问题也是海洋生态系统动力学理论研究的重要内容。并对海洋生态系统动力学模型及模拟的基本概念和了描述，进而说明建模时要注意抽象与简化。最后就我国开展海洋生态系统动力学研究提出了一点看法。  相似文献   

地形和层结变化对内潮生成影响的数值模拟研究     

刘昆  徐振华  尹宝树 《海洋科学》2016,40(11):148-154

基于ROMS(Regional Ocean Modeling System)模式,设计了9组理想数值实验,研究了内潮的产生对地形和背景层结环境的敏感性。结果表明:高斯海脊两侧地形梯度较大的超临界坡面处是内潮的主要源区;地形和层结环境的变化对内潮生成有很大影响;如地形和层结保持不变,不同的网格水平分辨率和垂向层数条件下估算的内潮转换率存在差别;地形和跃层的相对空间关系对内潮生成及其引起的水体混合强度存在影响。高分辨率的地形和合适的背景层结是内潮模拟的关键。该结论对于内潮形成的数值模拟研究有一定参考价值。  相似文献   

Monsoons across Multi-scales: Summary of Fourth Conference on Earth System Science     

Hao Qingzhen  Zhang Renhe  Wang Pinxian  Wang Bin 《地球科学进展》2016,31(7):689-699

The evolution and future projection of the regional and global monsoons, one of the major components of Earth climate system in the low-latitudes and middle-latitudes, has long been the research focus in the paleoclimate and modern climate communities. Session 4 of the 4^th Conference on Earth System Sciences (CESS) in Shanghai focused on the evolution, variability, and driving mechanism of regional and global monsoon system across multiple timescale, and the role of the monsoon system in changes in the Earth system. During the session, the issues of features of past and contemporary monsoons based on observation data and geological reconstruction, model simulation of past and contemporary monsoons, and response of monsoon climate to the past and present global warming were intensively discussed. The future research directions were also addressed.  相似文献   

琉球沟弧盆系的海底热流分布特征及冲绳海槽热演化的数值模拟   总被引：9，自引：0，他引：9  

栾锡武 《海洋与湖沼》1997,28(1):44-48

以１９９３－１９９５年对琉球沟弧盆系各个航次的热流数值进行了搜集整理，发现这一地区热流的分布特征和构造特征有明显的对应关系，大致上呈出现东西分带南北分块的分布特征，冲绳海槽有极高的热流值，而琉球海沟则有极低的热流值，这和板块的撞碰，俯冲，弧后扩张模式相吻合，用二维热传导平流议程用有限单元法对冲绳海槽进行的地球动力学热模拟显示，冲绳海槽的高热流值和海槽内的岩浆活动有着密切关系，如果不考虑海槽中岩浆因  相似文献   

Active open boundary forcing using dual relaxation time-scales in downscaled ocean models     

《Ocean Modelling》2015

Regional models actively forced with data from larger scale models at their open boundaries often contain motion at different time-scales (e.g. tidal and low frequency). These motions are not always individually well specified in the forcing data, and one may require a more active boundary forcing while the other exert less influence on the model interior. If a single relaxation time-scale is used to relax toward these data in the boundary equation, then this may be difficult. The method of fractional steps is used to introduce dual relaxation time-scales in an open boundary local flux adjustment scheme. This allows tidal and low frequency oscillations to be relaxed independently, resulting in a better overall solution than if a single relaxation parameter is optimized for tidal (short relaxation) or low frequency (long relaxation) boundary forcing. The dual method is compared to the single relaxation method for an idealized test case where a tidal signal is superimposed on a steady state low frequency solution, and a real application where the low frequency boundary forcing component is derived from a global circulation model for a region extending over the whole Great Barrier Reef, and a tidal signal subsequently superimposed.  相似文献   

Numerical evaluation of pumping well transmissivity estimates in laterally heterogeneous formations   总被引：1，自引：0，他引：1  

Leanne G. Tumlinson  James L. Osiensky  Jerry P. Fairley 《Hydrogeology Journal》2006,14(1-2):21-30

Transmissivity estimates derived from non-steady-state, single well, constant discharge, aquifer tests in laterally heterogeneous environments generally are questioned relative to their representativeness of aquifer conditions. Drawdown in pumping wells reflects the removal of water from storage in the aquifer and transient refraction of groundwater path-lines during the evolution of a non-symmetrical cone of depression. Simulations of single-well aquifer tests in aquifers with simple, arbitrary distributions of block heterogeneities suggest that transmissivity (T) values derived by the Cooper–Jacob (1946) method generally reflect volumetric, weighted mean T values of all of the heterogeneities contacted by the cone of depression at a particular time. This finding suggests that early-time drawdown data for single well aquifer tests reflect rapidly changing, volumetric, weighted mean T values proximal to the pumping well while late-time drawdown data reflect stabilized conditions and spatially averaged, volumetric weighted mean T out to a considerable distance from the pumping well.

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Resume Los estimados de transmisividad derivados de estados no estables, pozos individuales, descarga constante, pruebas de acuíferos en ambientes heterogéneos laterales generalmente se cuestionan en cuanto a su representatividad de las conidiones de los acuíferos. La extracción de agua en pozos de bombeo refleja la extracción de agua del depósito en el acuífero y la refracción transitoria de líneas de trayectoria del agua subterránea durante la evolución de un cono no simétrico de depresión. Las simulaciones de pozos individuales, pruebas de acuíferos en acuíferos con distribuciones simples, arbitrarias de heterogeneidades de bloque sugieren que los valores de transmisividad (T) derivados por el método Cooper–Jacob (1946) generalmente reflejan valores medios volumétricos potenciales (weighted) de todas las heterogeneidades en contaco con el cono de la depresión en un momento particular. Este descubrimiento sugiere que los datos de extracción tempranos de pruebas de pozos individuales reflejan valores medios potenciales volumétricos que cambian rápidamente en la proximidad del pozo de bombeo mientras que los valores de extracción tardíos reflejan condiciones estabilizadas y medias potenciales volumétricas a una distancia considerable del pozo de bombeo.

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Resumé Les estimés de transmissivité dérivés dessais de pompage en régime transitoire dans un seul puits contenu dans une formation latéralement hétérogène sont généralement questionable en ce qui concerne la représentativité des conditions de laquifère. Le rabattement dans les puits de pompage reflète lextraction deau provenant de lemmagasinement de laquifère et la réfraction en régime transitoire des lignes découlement durant lévolution dun cone de dépression non symétrique. Des simulations dessai de pompage dans un seul puits contenu dans un domaine avec des blocs hétérogènes distribués arbitrairement suggèrent que les valeurs de transmissivité obtenus avec la méthode dinterprétation de Cooper–Jacob (1946) sont généralement représentatifs du volume moyen pondéré de toutes les hétérogénéités en contact avec le cone de dépression à un temps particulier. Cette découverte suggère que les données de rabattement au début dun essai pour un seul puits reflètent un changement rapide des valeurs moyennes proximales pondérées tandis que le rabattement à un temps tardif reflète les conditions stabilisées et la moyenne spatiale jusquà une distance considérable du puits de pompage.

  相似文献   

增城市3维互动全景展示系统的建设与应用     

周婷婷  肖露子  曹凯滨 《测绘软科学研究》2012,(5):60-64

主要探讨增城市3维互动全景展示系统的建设方法、技术路线、关键技术及其在各个领域的应用。系统通过旅游和农业资源的整合,让大众了解增城旅游与农业资源,推动农业、旅游业和地理信息系统的产业化发展。此外,作为一个可持续发展的系统,今后在城市规划等相关领域也将发挥一定作用。  相似文献   

GIS-simulation of the spatial distribution of snow cover and observed ground temperatures in the Daisetsu Mountains,Japan     

《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(4):212-218

This paper describes one geometrical method of simulating the spatial distribution of snow cover. Geographical Information Systems (GIS) and precise Digital Elevation Model (DEM) were used in the simulation. The model is based on empirical parameters called coefficients depending on slope aspect and inclination. As a result, this model predicts that windward convex terrains remain snow-free during winter. This snow cover distribution was validated by usage of an air photograph taken in early spring, and the distribution of vegetation patches which represent the outer fringes of snow covered areas. Low ground temperatures together with high DC resistivities, which suggest the presence of permafrost, were identified in simulated snow-free areas.  相似文献   

A comparison of permafrost prediction models along a section of Trail Ridge Road, Rocky Mountain National Park, Colorado, USA   总被引：1，自引：0，他引：1  

Jason R. Janke  Mark W. Williams 《Geomorphology》2012,138(1):111-120

The distribution of mountain permafrost along Trail Ridge Road (TRR) in Rocky Mountain National Park, Colorado, was modeled using ‘frost numbers’ and a ‘temperature of permafrost model’ (TTOP) in order to assess the accuracy of prediction models. The TTOP model is based on regional observations of air temperature and heat transfer functions involving vegetation, soil, and snow; whereas the frost number model is based on site-specific ratios of ground temperature measurements of frozen and thawed degree-days. Thirty HOBO© temperature data loggers were installed near the surface as well as at depth (30 to 85 cm). From mid-July 2008 to 2010, the mean annual soil temperature (MAST) for all surface sites was − 1.5 °C. Frost numbers averaged 0.56; TTOP averaged − 1.8 °C. The MAST was colder on western-facing slopes at high elevations. Surface and deeper probes had similar MASTs; however, deeper probes had less daily and seasonal variation. Another model developed at the regional scale based on proxy indicators of permafrost (rock glaciers and land cover) classified 5.1 km² of permafrost within the study area, whereas co-kriging interpolations of frost numbers and TTOP data indicated 2.0 km² and 4.6 km² of permafrost, respectively. Only 0.8 km² were common among all three models. Three boreholes drilled within 2 m of TRR indicate that permafrost does not exist at these locations despite each borehole being classified as containing permafrost by at least one model. Addressing model uncertainty is important because nutrients stored within frozen or frost-affected soils can be released and impact alpine water bodies. The uncertainty also exposes two fundamental problems: empirical models designed for high latitudes are not necessarily applicable to mountain permafrost, and the presence of mountain permafrost in the alpine tundra of the Colorado Front Range has not been validated.  相似文献