A spatiotemporal indexing approach for efficient processing of big array-based climate data with MapReduce     

Zhenlong Li  Fei Hu  John L. Schnase  Daniel Q. Duffy  Tsengdar Lee  Michael K. Bowen 《International journal of geographical information science》2017,31(1):17-35

Climate observations and model simulations are producing vast amounts of array-based spatiotemporal data. Efficient processing of these data is essential for assessing global challenges such as climate change, natural disasters, and diseases. This is challenging not only because of the large data volume, but also because of the intrinsic high-dimensional nature of geoscience data. To tackle this challenge, we propose a spatiotemporal indexing approach to efficiently manage and process big climate data with MapReduce in a highly scalable environment. Using this approach, big climate data are directly stored in a Hadoop Distributed File System in its original, native file format. A spatiotemporal index is built to bridge the logical array-based data model and the physical data layout, which enables fast data retrieval when performing spatiotemporal queries. Based on the index, a data-partitioning algorithm is applied to enable MapReduce to achieve high data locality, as well as balancing the workload. The proposed indexing approach is evaluated using the National Aeronautics and Space Administration (NASA) Modern-Era Retrospective Analysis for Research and Applications (MERRA) climate reanalysis dataset. The experimental results show that the index can significantly accelerate querying and processing (~10× speedup compared to the baseline test using the same computing cluster), while keeping the index-to-data ratio small (0.0328%). The applicability of the indexing approach is demonstrated by a climate anomaly detection deployed on a NASA Hadoop cluster. This approach is also able to support efficient processing of general array-based spatiotemporal data in various geoscience domains without special configuration on a Hadoop cluster.  相似文献   

砂岩储层中原油微生物降解的模拟实验研究   总被引：22，自引：2，他引：22  

陈传平  梅博文 《沉积学报》1997,15(1):135-140

模拟辽河冷东-雷家地区的砂砾岩储层条件，采用该地区的正常原油，在３０℃恒温和充氧下以及有营养元素的水溶液中，进行了原油喜氧微生物降解实验。实验表明，经微生物降解后，原油的化学组成发生了较大变化，饱和烃含量下降，沥青质、非烃含量上升；水溶液的ｐＨ值下降，并在其中检测出了有机酸，可见在微生物的代谢过程中，原油中的烃类分子被部分转化为水溶性含氧酸性产物。降解实验的油样与取自同一地区的两个重质原油饱和烃气相色谱图比较，两者在组成上极其相近，其结果说明辽河油田的重油成因，是原油遭受了喜氧微生物的降解。实验对微生物降解过程的动力学进行了初步研究。微生物对饱和烃馏分中不同化合物的降解序列为:短链正构烷烃、长链正构烷烃、异构烷烃、环状烷烃。但当各组分间的浓度发生较大变化时，降解序列会有所不同。  相似文献   

The future of the past at Göreme in Turkey     

Robert Bowen 《Environmental Geology》1990,16(1):35-41

The structural conservation project at the Göreme circus, with its rock-hewn churches, is a program for safeguarding this area in Cappadocia. The aim of this paper is to inquire into the causes of observed degradation and define a general plan of intervention which associates processes controlling the development of the phenomena with appropriate repair technologies facilitating treatment of the most urgent cases of damage. The first problem noted is clearly erosion. To natural erosion must be added the effects of localized erosion resulting from increasing tourism on the site. The second difficulty is to be seen in fissuring and fracturing in the soft rock, a volcanic tuff. Treatment of fissures in domes involves complete covering of the rock. Also, it must be noted that low-pressure injection grouting with a product suitable for the fissures would assure water-tightness of the monument and restore to the massif its monolithic stability.  相似文献   

矿区水文地质研究进展及中长期发展方向   总被引：2，自引：0，他引：2  

张发旺  陈立  王滨  么红超  许柏青  李敏巍  胡博文  钱龙 《地质学报》2016,90(9):2464-2475

矿区水资源保护和矿山防治水这两个互相矛盾又紧密联系的问题给传统的矿山水文地质学带来了更多的挑战和机遇,迫切需要新理论、新技术的发展。为了更好的实现矿区未来地下水资源的开采、利用与保护以及采煤安全和区域水资源可持续利用,本文选择长治盆地为重点研究区,从采动引起的覆岩移动入手,在资料分析的基础上,采用相似材料模拟、综合物探、野外监测、现场注(压)水试验的方法,运用水文地质学原理研究了采煤引起含水层结构变异厚度及其渗透性变化特征;在此基础上,以长治盆地集中开采区水文地质条件和野外监测数据为基础,建立了区域地下水流场三维动态模拟试验台,为研究含水层结构变异后的地下水循环机理和水资源重新分布提供技术支撑;本文同时指出了我国矿山水文地质研究目前存在的问题和面临的挑战,分析了矿山水文地质学科的发展趋势,展望了未来相关分支学科和关键核心技术的发展方向与前景。  相似文献   

Early middle Miocene tectonic uplift of the northwestern part of the Qinghai–Tibetan Plateau evidenced by geochemical and mineralogical records in the western Tarim Basin     

Chaowen Wang  Hanlie Hong  Hemmo A. Abels  Zhaohui Li  Kai Cao  Ke Yin  Bowen Song  Yadong Xu  Junliang Ji  Kexin Zhang 《International Journal of Earth Sciences》2016,105(3):1021-1037

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Removal of fluoride ion from groundwater by adsorption on lanthanum and aluminum loaded clay adsorbent     

Shengyu Zhang  Ying Lyu  Xiaosi Su  Yuya Bian  Bowen Yu  Yuling Zhang 《Environmental Earth Sciences》2016,75(5):401

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Recruitment of cod and haddock in the North Atlantic: a comparative analysis   总被引：1，自引：1，他引：1  

Fogarty  Michael J.; Myers  Ransom A.; Bowen  Keith G. 《ICES Journal of Marine Science》2001,58(5):952-961

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基于SLAMM模型的海平面上升对广西沿海红树林影响研究     

潘嵩  王慧  李欢  李文善  徐浩  金波文 《海洋通报》2020,39(3):325-334

本文基于SLAMM模型分析了不同情景下海平面上升对广西沿海红树林分布面积的影响及其空间差异,通过对比实验定量分析了潮差和沉积速率的作用。结果显示,与基准年2007年相比,2100年广西红树林面积在当前海平面上升速率、典型浓度路径RCP2.6、RCP4.5和RCP8.5情景下分别减少0.57%、4.99%、7.99%和17.39%,珍珠港、茅尾海、丹兜海和英罗港受影响程度较大。当地潮差与红树林面积减少率呈负相关关系。需维持红树林生长区域的沉积速率以应对未来的海平面加速上升。  相似文献   

Remote Sensing of Mangrove Change Along the Tanzania Coast     

Yeqiao Wang  Gregory Bonynge  Jarunee Nugranad  Michael Traber  Amani Ngusaru  James Tobey  Lynne Hale  Robert Bowen  Vedast Makota 《Marine Geodesy》2003,26(1):35-48

This article contributes to the understanding of the changes in distribution and total area of mangrove forests along the mainland Tanzania coast over the past decade. Mangroves are recognized as critical coastal habitat requiring protection and special attention. The Tanzania coastline forms a suitable habitat for establishment of mangrove forests. Mangrove forests are distributed from Tanga in the north to Mtwara in the south covering approximately 109,593 hectares from 1988-1990 and about 108,138 hectares in 2000. The largest continuous mangrove stands are found in the districts of Rufiji, Kilwa, Tanga-Muheza, and Mtwara. Comparison of data between these two time periods shows that the geographic coverage of mangroves has no dramatic change in the past decade. The Tanzania Mangrove Management Project and other closely related programs and efforts pertaining to mangrove conservation contribute to direct restoration and natural regeneration of mangroves. This study documents the changes of mangroves and demonstrates that remote sensing and GIS offer important data and tools in the advancement of coastal resource management and ecosystem monitoring. Application of geographic information technologies is critical for improved coastal resources management and decision making for sustainable development in Tanzania.  相似文献   

The Hawaii-2 Observatory   总被引：2，自引：0，他引：2  

Petitt  R.A.  Jr. Harris  D.W. Wooding  B. Bailey  J. Jolly  J. Hobart  E. Chave  A.D. Duennebier  F. Butler  R. Bowen  A. Yoerger  D. 《Oceanic Engineering, IEEE Journal of》2002,27(2):245-253

A permanent deep ocean scientific research facility-the Hawaii-2 Observatory (H2O)-was installed on the retired HAW-2 commercial submarine telephone cable in September 1998. H2O consists of a seafloor submarine cable termination and junction box in 5000 m of water located halfway between Hawaii and California. The H2O infrastructure was installed from a large research vessel using the Jason ROV and standard over-the-side gear. The junction box provides two-way digital communication at variable data rates of up to 80 kbit/s using the RS-422 protocol and a total of 400 W of power for both junction box systems and user equipment. Instruments may be connected by an ROV to the junction box at 8 wet-mateable connectors. The H2O junction box is a "smart" design, which incorporates redundancy to protect against failure and allows full control of instrument functionality from shore. Initial instrumentation at the H2O site includes broad-band seismometer and hydrophone packages  相似文献