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植被冠层热点的季相和日相变化

遥感学报 2002年第4期6卷 241-245页

作者：苏理宏李小文 A Stralher E Tsvetsinskay 王锦地北京师范大学遥感与GIS研究中心北京100875 Center for Remote Sensing and dept of geography Boston University

随着热点卫星Triana的即将发射 ,地表热点季相和日相变化的研究变得日益重要。以几种植被冠层为例 ,采用计算机模拟的方法考查冠层热点的季相和日相变化。

关键词：植被冠层热点遥感模型计算机模拟可视化季相变化日相变化

A hierarchical indexing strategy for optimizing Apache Spark with HDFS to efficiently query big geospatial raster data

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International Journal of Digital Earth 2020年第3期13卷 410-428页

作者： Fei Hu Chaowei Yang Yongyao Jiang Yun Li Weiwei Song Daniel Q.Duffy John L.Schnase Tsengdar Lee NSF Spatiotemporal Innovation Center and dept.of geography and GeoInformation Sciences George Mason UniversityFairfaxVAUSA Center for Open-Source Data and AI Technologies IBMSan FranciscoCAUSA Office of Computational and Information Sciences and Technology NASA Goddard Space Flight CenterGreenbeltMDUSA NASA Center for Climate Simulation Goddard Space Flight CenterGreenbeltMDUSA Earth Science Division NASA HeadquartersWashingtonDCUSA

Earth observations and model simulations are generating big multidimensional array-based raster ***,it is difficult to efficiently query these big raster data due to the inconsistency among the geospatial raster data model,distributed physical data storage model,and the data pipeline in distributed computing *** efficiently process big geospatial data,this paper proposes a three-layer hierarchical indexing strategy to optimize Apache Spark with Hadoop Distributed File System(HDFS)from the following aspects:(1)improve I/O efficiency by adopting the chunking data structure;(2)keep the workload balance and high data locality by building the global index(k-d tree);(3)enable Spark and HDFS to natively support geospatial raster data formats(e.g.,HDF4,NetCDF4,GeoTiff)by building the local index(hash table);(4)index the in-memory data to further improve geospatial data queries;(5)develop a data repartition strategy to tune the query parallelism while keeping high data *** above strategies are implemented by developing the customized RDDs,and evaluated by comparing the performance with that of Spark SQL and *** proposed indexing strategy can be applied to other distributed frameworks or cloud-based computing systems to natively support big geospatial data query with high efficiency.

关键词： Big data hierarchical indexing multi-dimensional Apache Spark HDFS distributed computing GIS

The effects of water flow and temperature on thermal regime around a culvert built on permafrost

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Research in Cold and Arid Regions 2014年第5期6卷 415-422页

作者： Loriane Périer Guy Doré C.R.Burn Loriane Perier Guy Dore C. R. Bum Laval University Center for Northern Studies (CEN) 1035 Avenue De la m~decine QuObec Canada G1A OA6 Carleton University Dept. of Geography and Environmental Studies Ottawa Ontario Canada K1S 5B6

Temperature and water flow through a culvert beneath the Alaska Highway near Beaver Creek,Yukon,were measured at hourly intervals between June and October *** data were used to simulate the effect of the culvert on the thermal regime of the road embankment and subjacent permafrost.A 2-D thermal model of the embankment and permafrost was developed with TEMP/W and calibrated using field *** relations were obtained between water temperatures at the entrance to the culvert,flow into the culvert,and water temperatures inside the *** temperatures at the entrance and inside the culvert had a linear relation,while water temperatures inside the culvert and water flow were associated by a logarithmic relation.A multiple linear regression was used to summarize these *** this relationship,changes in the flow rate and water temperatures at the entrance of the culvert were simulated to obtain predicted water temperatures in the *** temperatures in the culvert were used in the thermal model to determine their effects on the ground thermal regime near the *** of ±10% in water flow rate had no impact on the thermal regime underneath the *** of water temperature at the entrance of the culvert had a noticeable influence on the thermal regime.A final simulation was conducted without insulation beneath the *** thaw depth was 30 cm with insulation,and 120 cm without insulation,illustrating the importance of insulation to the ground thermal regime.

关键词： culvert thermal regime water flow water temperature modeling permafrost

Mechanisms associated with winter intraseasonal extreme sea ice extent in the Weddell Sea

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Advances in Polar Science 2017年第3期28卷 171-184页

作者： Fabio Ullmann Furtado de LIMA Leila M.V.CARVALHO Centro de Ensino Superior da Foz do Itajaí-Univ. do Estado de Santa Catarina (UDESC) dept.of geography and Earth Research Institute University of California Santa Barbara

Previous studies have shown evidence of atmospheric extratropical wave trains modulating sea ice area in the Weddell and Amundsen/Bellingshausen seas on intraseasonal time-scales(20–100 d). Here we investigate mechanisms relating intraseasonal extreme sea ice extent and Ekman layer dynamics with emphasis on the Weddell Sea. This study extends from 1989 to 2013 and focuses on the winter season. Wind stress τ is calculated with winds from the Climate Forecast System reanalysis(CFSR) to evaluate momentum transfer between the atmosphere and the Ekman layer. Lag-composites of the anomalies of Ekman transport and the Ekman pumping indicate that divergence of mass in the Ekman layer and upwelling lead the occurrence of extreme sea ice contraction on intraseasonal time-scales in the Weddell Sea. Opposite conditions(i.e., convergence of the mass and downwelling) lead extreme sea ice expansion on intraseasonal time-scales. This study suggests that the Ekman pumping resulting from the anomalous wind stress on intraseasonal time-scales can transport these warmer waters to the surface contributing to sea ice melting. Additionally, high resolution sea ice fraction and ocean currents obtained from satellite and in situ data are used to investigate in detail mechanisms associated with persistent extreme sea ice expansion and contraction on intraseasonal time-scales. These case studies reveal that atmospheric circumpolar waves on intraseasonal time-scales can induce contrasting anomalies of about ±20% in sea ice concentration at the Weddell and western Antarctica Peninsula margins within less than 30 d. This study shows that extreme anomalies in sea ice may lag between 5–25 d(1–5 pentads) the ocean-atmospheric forcing on intraseasonal time-scales.

关键词： sea ice extent intraseasonal time-scales Ekman layer dynamics

How crustal-scale strike-slip faults initiate: the Ailao Shan-Red River fault zone and the East Himalaya syntaxis as a result of the two-stage India-Asia collision

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How crustal-scale strike-slip faults initiate: the Ailao Sha...

2014年中国地球科学联合学术年会——专题52：青藏高原及邻区新生代构造

作者： Shuyun Cao Franz Neubauer State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences dept. geography and Geology University of Salzburg Hellbrunner Str. 34A-5020 Salzburg Austria

Crustal-scale strike-slip faults present one the most important geodynamic processes affecting the lithosphere-asthenosphere *** major question is how and where a major strike-slip initiates and further ***,we propose...

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空间数据通用理论存在的可能性

导航定位学报 2004年第1期 29-30页

作者： Moellering H 蒙印 dept of geography Ohio State University 1036 Derby HallColumbusOhioU. a A. 43210)

过去40年期间,空间数据的概念及概念编码 (从现实世界到空间对象领域)都有了显著发展。目前,许多研究者提出一种新构想:以某种方式融合不同的空间数据结构(例如栅格、矢量数据结构),生成某种在概念和操作上一体的混合数据结构。本文基... 详细信息

过去40年期间,空间数据的概念及概念编码 (从现实世界到空间对象领域)都有了显著发展。目前,许多研究者提出一种新构想:以某种方式融合不同的空间数据结构(例如栅格、矢量数据结构),生成某种在概念和操作上一体的混合数据结构。本文基于这种思想,根据现有理论探讨了空间数据当前发展状况并指出未来研究的可能方向。本文主要讨论数据结构和是否可能存在一种这样的通用结构。

关键词：解析制图空间数据深度结构分析制图理论

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武隆喀斯特及其地壳抬升性质解读

中国岩溶 2007年第2期26卷 119-125页

作者：朱学稳陈伟海 Erin Lynch 中国地质科学院岩溶地质研究所 Hoffman Environmental Research Institute dept. of geography and Geology Western Kentucky University Bowling GreeKY 42101 USA

在特定的地质结构及峡谷水文网分布条件下,武隆喀斯特以独立发育的诸多包气带喀斯特系统为主要特征,而且不同喀斯特系统间的结构与形态组成差异甚大。喀斯特系统的分析可解读相适应的地壳运动性质是:自新近纪末期以来,地壳运动只有上升... 详细信息

在特定的地质结构及峡谷水文网分布条件下,武隆喀斯特以独立发育的诸多包气带喀斯特系统为主要特征,而且不同喀斯特系统间的结构与形态组成差异甚大。喀斯特系统的分析可解读相适应的地壳运动性质是:自新近纪末期以来,地壳运动只有上升没有下降过程;前80～100万年为持续上升,即几乎没有相对稳定的经历;继后是间歇性抬升与相对稳定,似以后者占优;分布于深切峡谷相对高度150～300m间的大型成层性洞穴,主要发育于中更新世;晚更新世以来的上升与相对稳定彼此平分秋色。

关键词：武隆喀斯特喀斯特系统地壳抬升

Evaluation of Sediment Yield Predicting Models of Ghana

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Journal of Geographical Research 2021年第1期4卷 37-47页

作者： John Manyimadin Kusimi Bertha Ansaah Kusimi Barnabas A.Amisigo dept.of geography&Resource Development University of GhanaLegonAccraGhana Institute of Environment and Sanitation Studies University of GhanaLegonAccraGhana Water Research Institute Council for Scientific&Industrial ResearchP.O.Box AH.38AccraGhana

Fluvial sediment transport data is a very important data for effective water resource ***,acquiring this data is expensive and tedious hence sediment yield modeling has become an alternative approach in estimating river sediment *** Ghana,several sediment yield predicting models have been developed to estimate the sediment yields of ungauged rivers including the Pra River *** this paper,10 months sediment yield data of the Pra River Basin was used to evaluate the existing sediment yield predicting models of Ghana.A regression analysis between predicted sediment yield data derived from the models and the observed suspended sediment yields of the Pra Basin was done to determine the extent of estimation of observed sediment *** prediction of suspended sediment yield was done for 4 out of 5 existing sediment yield predicting models in *** were variations in sediment yield between observed and predicted suspended *** predicted sediment yields were lower than observed data except for equation 3 where the results were *** models were found to be good estimators of fluvial sediments with the best model being equation *** yield tends to increase with drainage basin area.

关键词： Pra River Regression analysis Sediment transport Sediment yield Sediment yield modeling Ghana

Natural siliceous dust and human health: Pathways, toxicity, and impact

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Chinese Journal Of Geochemistry 2006年第B8期25卷 219-219页

作者： Edward Derbyshire Centre for Quaternary Research dept. of geography Royal Holloway University of London UK