Automated Detection of Coronal Loops Using a Wavelet Transform Modulus Maxima Method     

R. T. James McAteer  Pierre Kestener  Alain Arneodo  Andre Khalil 《Solar physics》2010,262(2):387-397

We propose and test a wavelet transform modulus maxima method for the automated detection and extraction of coronal loops in extreme ultraviolet images of the solar corona. This method decomposes an image into a number of size scales and tracks enhanced power along each ridge corresponding to a coronal loop at each scale. We compare the results across scales and suggest the optimum set of parameters to maximize completeness, while minimizing detection of noise. For a test coronal image, we compare the global statistics (e.g. number of loops at each length) to previous automated coronal-loop detection algorithms.  相似文献   

Factors driving the biogeochemical budget of the Amazon River and its statistical modelling     

Vincent Bustillo  Reynaldo Luiz Victoria  Jose Mauro Sousa de Moura  Daniel de Castro Victoria  Andre Marcondes Andrade Toledo  Erich Collicchio 《Comptes Rendus Geoscience》2011,343(4):261-277

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Evaluating next-generation intensity–duration–frequency curves for design flood estimates in the snow-dominated western United States     

Hongxiang Yan  Ning Sun  Mark Wigmosta  L. Ruby Leung  Zhangshuan Hou  Andre Coleman  Richard Skaggs 《水文研究》2020,34(5):1255-1268

Civil infrastructure such as culverts and bridges are commonly designed using precipitation-based intensity–duration–frequency (PREC-IDF) curves, which assume that the occurrence of precipitation is in the form of rainfall and immediately available for the rainfall-runoff process. In snow-dominated regions, where most winter precipitation occurs as snow that melts during spring to early summer, the use of standard PREC-IDF curves may lead to substantial underestimation of design floods and high failure risk of infrastructure. In this context, we developed next-generation IDF (NG-IDF) curves that characterize the actual water reaching the land surface (i.e., rainfall plus snowmelt) to enhance standard infrastructure design in snow-dominated regions. This study evaluates the performance of NG-IDF curves coupled with U.S. Department of Agriculture Technical Release 55 hydrologic model in estimating design floods for 246 snowy locations in different hydroclimate regimes of the western United States. Design flood estimates from a well-validated continuous simulation using a physics-based hydrologic model, the Distributed Hydrology Soil Vegetation Model (DHSVM), were used as the performance benchmark. Compared with the benchmark estimates, the standard PREC-IDF curves led to substantial errors in design flood estimates, while the NG-IDF curves significantly reduced these errors. For example, the averaged error in the 50-year design flood estimates over the 246 locations was reduced from 31% with the use of PREC-IDF curves to 12% with the use of NG-IDF curves. Despite the different model structures, the single-event NG-IDF approach versus the continuous simulation DHSVM did not exhibit statistically significant differences in 91% of the 246 locations for the 50-year design flood estimates. This indicates a satisfactory performance of NG-IDF curves to estimate design flow under the conditions tested in the snow-dominated western United States. This article also presents technical suggestions and the limitations of infrastructure design using NG-IDF curves for regulatory agencies and practicing engineers.  相似文献   

Estimating end effects in trawl catches     

Battaglia  Andre; Trenkel  Verena M.; Rochet  Marie-Joelle 《ICES Journal of Marine Science》2006,63(5):956-959

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Absolute Accuracy and Repeatability of the Rmib Radiometers for Tsi Measurements     

Sabri Mekaoui  Steven Dewitte  Dominique Crommelynck  Andre Chevalier  Christian Conscience  Alexandre Joukoff 《Solar physics》2004,224(1-2):237-246

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Testing Nano-Powder and Fused-Glass Mineral Reference Materials for In Situ Rb-Sr Dating of Glauconite,Phlogopite, Biotite and Feldspar via LA-ICP-MS/MS     

Ahmad Redaa  Juraj Farkaš  Sarah Gilbert  Alan S. Collins  Stefan Löhr  Davood Vasegh  Marnie Forster  Morgan Blades  Thomas Zack  Andrea Giuliani  Roland Maas  Andre Baldermann  Martin Dietzel  Dieter Garbe-Schönberg 《Geostandards and Geoanalytical Research》2023,47(1):23-48

Reference materials (RMs) with well-characterised composition are necessary for reliable quantification and quality control of isotopic analyses of geological samples. For in situ Rb-Sr analysis of silicate minerals via laser ablation inductively coupled plasma tandem mass spectrometry (LA-ICP-MS/MS) with a collision/reaction cell, there is a general lack of mineral-specific and matrix-matched RMs, which limits wider application of this new laser-based dating technique to certain minerals. In this work, pressed nano-powder pellets (NP) of four RMs, GL-O (glauconite), Mica-Mg (phlogopite), Mica-Fe (biotite) and FK-N (K-feldspar), were analysed and tested for in situ Rb-Sr dating, complemented by isotope dilution (ID) MC-ICP-MS Rb-Sr analyses of GL-O and Mica-Mg. In addition, we attempted to develop alternative flux-free and fused ‘mineral glasses’ from the above RMs for in situ Rb-Sr dating applications. Overall, the results of this study showed that among the above RMs only two NP (Mica-Mg-NP and GL-O-NP) were suitable and robust for in situ dating applications. These two nano-powder reference materials, Mica-Mg-NP and GL-O-NP, were thus used as primary RMs to normalise and determine Rb-Sr ages for three natural minerals: MDC phlogopite and GL-O glauconite grains, and also Mica-Fe-NP (biotite). Our in situ analyses of the above RMs yielded Rb-Sr ages that are in good agreement (within 8%) of published ages, which suggests that both Mica-Mg-NP and GL-O-NP are suitable RMs for in situ Rb-Sr dating of phlogopite, glauconite and biotite. However, using secondary RMs is recommended to monitor the quality of the obtained ages.  相似文献   

Fissures in localizing urban sustainability: the case of Rwanda     

Malonza  Josephine Mwongeli  Ortega  Arnisson Andre 《GeoJournal》2022,87(1):147-166

GeoJournal - Heralded as a paragon of sustainability in Africa, Rwanda’s development programs and plans have been attuned to global narratives of sustainability, particularly the SDGs....  相似文献   

Probabilistic Tsunami Hazard Assessment (PTHA) for resilience assessment of a coastal community     

Hyoungsu Park  Daniel T. Cox  Andre R. Barbosa 《Natural Hazards》2018,94(3):1117-1139

Probabilistic Tsunami Hazard Analysis (PTHA) can be used to evaluate and quantify tsunami hazards for planning of integrated community-level preparedness, including mitigation of casualties and dollar losses, and to study resilient solutions for coastal communities. PTHA can provide several outputs such as the intensity measures (IMs) of the hazard quantified as a function of the recurrence interval of a tsunami event. In this paper, PTHA is developed using a logic tree approach based on numerical modeling for tsunami generated along the Cascadia Subduction Zone. The PTHA is applied to a community on the US Pacific Northwest Coast located in Newport, Oregon. Results of the PTHA are provided for five IMs: inundation depth, flow speed, specific momentum flux, arrival time, and duration of inundation. The first three IMs are predictors of tsunami impact on the natural and built environment, and the last two are useful for tsunami evacuation and immediate response planning. Results for the five IMs are presented as annual exceedance probability for sites within the community along several transects with varying bathymetric and topographic features. Community-level characteristics of spatial distribution of each IM for three recurrence intervals (500, 1000, 2500 year) are provided. Results highlight the different pattern of IMs between land and river transects, and significant magnitude variation of IMs due to complex bathymetry and topographic conditions at the various recurrence intervals. IMs show relatively higher magnitudes near the coastline, at the low elevation regions, and at the harbor channel. In addition, results indicate a positive correlation between inundation depth and other IMs near the coastline, but a weaker correlation at inland locations. Values of the Froude number ranged 0.1–1.0 over the inland inundation area. In general, the results in this study highlight the spatial differences in IMs and suggest the need to include multiple IMs for resilience planning for a coastal community subjected to tsunami hazards.  相似文献   

The Vicência meteorite fall: A new unshocked (S1) weakly metamorphosed (3.2) LL chondrite          下载免费PDF全文

Klaus Keil  Maria E. Zucolotto  Alexander N. Krot  Patricia M. Doyle  Myriam Telus  Tatiana V. Krot  Richard C. Greenwood  Ian A. Franchi  John T. Wasson  Kees C. Welten  Marc W. Caffee  Derek W. G. Sears  My Riebe  Rainer Wieler  Edivaldo dos Santos  Rosa B. Scorzelli  Jerome Gattacceca  France Lagroix  Matthias Laubenstein  Julio C. Mendes  Philippe Schmitt‐Kopplin  Mourad Harir  Andre L. R. Moutinho 《Meteoritics & planetary science》2015,50(6):1089-1111

The Vicência meteorite, a stone of 1.547 kg, fell on September 21, 2013, at the village Borracha, near the city of Vicência, Pernambuco, Brazil. It was recovered immediately after the fall, and our consortium study showed it to be an unshocked (S1) LL3.2 ordinary chondrite. The LL group classification is based on the bulk density (3.13 g cm^?3); the chondrule mean apparent diameter (0.9 mm); the bulk oxygen isotopic composition (δ¹⁷O = 3.768 ± 0.042‰, δ¹⁸O = 5.359 ± 0.042‰, Δ¹⁷O = 0.981 ± 0.020‰); the content of metallic Fe,Ni (1.8 vol%); the Co content of kamacite (1.73 wt%); the bulk contents of the siderophile elements Ir and Co versus Au; and the ratios of metallic Fe⁰/total iron (0.105) versus total Fe/Mg (1.164), and of Ni/Mg (0.057) versus total Fe/Mg. The petrologic type 3.2 classification is indicated by the beautifully developed chondritic texture, the standard deviation (~0.09) versus mean Cr₂O₃ content (~0.14 wt%) of ferroan olivine, the TL sensitivity and the peak temperature and peak width at half maximum, the cathodoluminescence properties of chondrules, the content of trapped ¹³²Xe_tr (0.317 × 10^?8cm³STP g^?1), and the Raman spectra for organic material in the matrix. The cosmic ray exposure age is ~72 Ma, which is at the upper end of the age distribution of LL group chondrites. The meteorite is unusual in that it contains relatively large, up to nearly 100 μm in size, secondary fayalite grains, defined as olivine with Fa_>75, large enough to allow in situ measurement of oxygen and Mn‐Cr isotope systematics with SIMS. Its oxygen isotopes plot along a mass‐dependent fractionation line with a slope of ~0.5 and Δ¹⁷O of 4.0 ± 0.3‰, and are similar to those of secondary fayalite and magnetite in the unequilibrated chondrites EET 90161, MET 96503, and Ngawi. These data suggest that secondary fayalite in Vicência was in equilibrium with a fluid with a Δ¹⁷O of ~4‰, consistent with the composition of the fluid in equilibrium with secondary magnetite and fayalite in other unequilibrated ordinary chondrites. Secondary fayalite and the chondrule olivine phenocrysts in Vicência are not in isotopic equilibrium, consistent with low‐temperature formation of fayalite during aqueous alteration on the LL parent body. That alteration, as dated by the ⁵³Mn‐⁵³Cr chronology age of secondary fayalite, took place $4.0{}_{?1.1}^{+1.4}$ Ma after formation of CV CAIs when anchored to the quenched angrite D'Orbigny.  相似文献   

Erratum: Geostatistical Space–Time Models: A Review     

Phaedon Kyriakidis  Andre G. Journel 《Mathematical Geology》2000,32(7):893

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