Comparison of regression-based and combined versions of Inverse Distance Weighted methods for spatial interpolation of daily mean temperature data     

Emine?Tan?r Kay?k??Email author  Selma?Zengin Kazanc? 《Arabian Journal of Geosciences》2016,9(17):690

This paper focuses on the performance of two regression-based and one Inverse Distance Weighted (IDW) and two combined versions of IDW methods for interpolation of daily mean temperature at the Black Sea Region of Turkey. Simple linear regression (SLR) and multiple linear regression (MLR) are used as regression-based methods. Combinations of IDW with TLR (temperature lapse rate) and gradient plus inverse distance squared (GIDS) are used as combined versions of IDW. This study targets to compare five spatial interpolation methods based on RMSE (root-mean-square error) statistics of interpolation errors for daily mean temperatures from 1981 to 2012. In order to compare the interpolation errors of the five methods, the leave-one-out cross-validation method was applied over long periods of 32 years on 52 different sites. The algorithms of the five interpolation methods’ codes were written in MATLAB by the authors of the paper.  相似文献   

ISRM Suggested Method for Step-Rate Injection Method for Fracture In-Situ Properties (SIMFIP): Using a 3-Components Borehole Deformation Sensor     

Yves Guglielmi  Frederic Cappa  Hervé Lançon  Jean Bernard Janowczyk  Jonny Rutqvist  C. F. Tsang  J. S. Y. Wang 《Rock Mechanics and Rock Engineering》2014,47(1):303-311

  相似文献   

Tchabal Gangdaba massif in the Cameroon Volcanic Line: a bimodal association     

Zénon Itiga  Jacques-Marie Bardintzeff  Pierre Wotchoko  Pierre Wandji  Hervé Bellon 《Arabian Journal of Geosciences》2014,7(11):4641-4664

Tchabal Gangdaba (TG) volcanic massif, which is a part of the continental sector of the Cameroon Volcanic Line (CVL), is dated between 34.4 and 25.1 Ma. It displays mafic lavas (picrobasalt and basanite, 41–43 wt % SiO₂) and felsic lavas (rhyolite, 68–73 wt % SiO₂). The lack of intermediate rocks evidences a pronounced Daly gap between 43 and 68 wt % SiO₂, which corresponds to an important time span of 3.4 Ma. It is interpreted as due to extensive fractional crystallization under peculiar thermodynamical conditions. Felsic lavas yield strong negative anomalies in Ba, Sr and Eu (0.1?206Pb/²⁰⁴Pb?207Pb/²⁰⁴Pb?208Pb/²⁰⁴Pb?相似文献   

Remotely sensed rivers in the Anthropocene: state of the art and prospects     

Hervé Piégay  Fanny Arnaud  Barbara Belletti  Mélanie Bertrand  Simone Bizzi  Patrice Carbonneau  Simon Dufour  Frédéric Liébault  Virginia Ruiz-Villanueva  Louise Slater 《地球表面变化过程与地形》2020,45(1):157-188

The rivers of the world are undergoing accelerated change in the Anthropocene, and need to be managed at much broader spatial and temporal scales than before. Fluvial remote sensing now offers a technical and methodological framework that can be deployed to monitor the processes at work and to assess the trajectories of rivers in the Anthropocene. In this paper, we review research investigating past, present and future fluvial corridor conditions and processes using remote sensing and we consider emerging challenges facing fluvial and riparian research. We introduce a suite of remote sensing methods designed to diagnose river changes at reach to regional scales. We then focus on identification of channel patterns and acting processes from satellite, airborne or ground acquisitions. These techniques range from grain scales to landform scales, and from real time scales to inter-annual scales. We discuss how remote sensing data can now be coupled to catchment scale models that simulate sediment transfer within connected river networks. We also consider future opportunities in terms of datasets and other resources which are likely to impact river management and monitoring at the global scale. We conclude with a summary of challenges and prospects for remotely sensed rivers in the Anthropocene. © 2019 John Wiley & Sons, Ltd.  相似文献   

Use of terrestrial photosieving and airborne topographic LiDAR to assess bed grain size in large rivers: a study on the Rhine River     

Valentin Chardon  Laurent Schmitt  Hervé Piégay  Dimitri Lague 《地球表面变化过程与地形》2020,45(10):2314-2330

Most grain size monitoring is still being conducted by manual sampling in the field, which is time consuming and has low spatial representation. Due to new remote sensing methods, some limitations have been partly overcome, but methodological progress is still needed for large rivers as well as in underwater conditions. In this article, we tested the reliability of two methods along the Old Rhine River (France/Germany) to estimate the grain size distribution (GSD) in above-water conditions: (i) a low-cost terrestrial photosieving method based on an automatic procedure using Digital Grain Size (DGS) software and (ii) an airborne LiDAR topo-bathymetric survey. We also tested the ability of terrestrial photosieving to estimate the GSD in underwater conditions. Field pebble counts were performed to compare and calibrate both methods. The results showed that the automatic procedure of terrestrial photosieving is a reliable method to estimate the GSD of sediment patches in both above-water and underwater conditions with clean substrates. Sensitivity analyses showed that environmental conditions, including solar lighting conditions and petrographic variability, significantly influence the GSD from the automatic procedure in above-water conditions. The presence of biofilm in underwater conditions significantly altered the GSD estimation using the automatic procedure, but the proposed manual procedure overcame this problem. The airborne LiDAR topographic survey is an accurate method to estimate the GSD of above-water bedforms and is able to generate grain size maps. The combination of terrestrial photosieving and airborne topographic LiDAR methods is adapted to assess the GSD over several kilometers long reaches of large rivers. © 2020 John Wiley & Sons, Ltd.  相似文献   

Proglacial sediment dynamics from daily to seasonal scales in a glaciated Alpine catchment (Bossons glacier,Mont Blanc massif,France)          下载免费PDF全文

Hervé Guillon  Jean‐Louis Mugnier  Jean‐François Buoncristiani 《地球表面变化过程与地形》2018,43(7):1478-1495

The sediment yields of Alpine catchments are commonly determined from streamload measurements made some distance downstream from glaciers. However, this approach indiscriminately integrates erosion processes occurring in both the glacial and proglacial areas. A specific method is required to ascertain the respective inputs from (i) subglacial and supraglacial sediments, (ii) proglacial hillslopes and (iii) proglacial alluvial areas or sandurs. This issue is addressed here by combining high‐resolution monitoring (2 min) of suspended sediment concentrations at different locations within a catchment with discharge gauging and precipitation data. This methodological framework is applied to two proglacial streams draining the Bossons glacier (Mont Blanc massif, France): the Bossons and Crosette streams. For the Bossons stream, discharge and suspended load data were acquired from June to October 2013 at 1.15 and 1.5 km from the glacial terminus, respectively upstream and downstream from a small valley sandur. These hydro‐sedimentary data are compared with the Crosette stream dataset acquired at the outlet of the Bossons glacier subglacial drainage system. A fourfold analysis focusing on seasonal changes in streamload and discharge, multilinear regression modelling, evaluation of the sandur flux balance and probabilistic uncertainty assessment is used to determine the catchment sediment budget and to explain the proglacial sediment dynamics. The seasonal fluctuation of the sediment signal observed is related to the gradual closing of the subglacial drainage network and to the role of the proglacial area in the sediment cascade: the proglacial hillslopes appear to be disconnected from the main channel and the valley sandur acts as a hydrodynamic sediment buffer both daily and seasonally. Our findings show that an understanding of proglacial sediment dynamics can help in evaluating paraglacial adjustment and subglacial erosion processes. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Water intrusions and particle signatures in the Black Sea: a Biogeochemical-Argo float investigation     

Emil Vassilev Stanev  Sebastian Grayek  Hervé Claustre  Chaterine  Schmechtig  Antoine Poteau 《Ocean Dynamics》2017,67(9):1119-1136

Continuous observations during 3 years with a vertical resolution of 1 dbar from two Bio-Argo floats in the Black Sea that were equipped with oxygen optodes, chlorophyll fluorometers, and backscattering sensors are analyzed. The particle backscattering coefficient, b _bp provides a proxy for the concentration of suspended particles. The observations clearly identify thermal and b _bp intrusions down to ~700–800 m in the Bosporus inflow area. In this area, b _bp is more than five times larger than elsewhere, which could indicate bacterial abundance and possible biological involvement in the precipitation of Mn-containing particles. The b _bp anomalies become much shallower than the temperature anomalies with increasing distance to the east of the strait. Their maxima are located between the onset of the suboxic zone and the upper part of the anoxic layer. Unlike well-known intrusions that are caused by inflow, open ocean intrusions are shallower and often characterized by multiple layers of backscatter maxima with thicknesses of only 15–20 m. The ratio between backscattering coefficients measured at two wavelengths, which gives a proxy for particle size, shows that the relative amount of larger size particles in the anoxic layer increases with depth. The particle concentrations and their size distribution display different vertical variability, which indicates the complex transformation of biological matter. The lower concentration of particles and lower chlorophyll-a during the extremely warm 2016 reveals an overall positive correlation between the two properties. The trends in the particle backscattering coefficient in the suboxic zone during 2013–2016 could indirectly reveal a biogeochemical response to temperature changes.  相似文献   

Estimation of large wood budgets in a watershed and river corridor at interdecadal to interannual scales in a cold‐temperate fluvial system          下载免费PDF全文

Maxime Boivin  Thomas Buffin‐Bélanger  Hervé Piégay 《地球表面变化过程与地形》2017,42(13):2199-2213

Large wood (LW) is a ubiquitous feature in rivers of forested watersheds worldwide, and its importance for river diversity has been recognized for several decades. Although the role of LW in fluvial dynamics has been extensively documented, there is a need to better quantify the most significant components of LW budgets at the river scale. The purpose of our study was to quantify each component (input, accumulation, and output) of a LW budget at the reach and watershed scales for different time periods (i.e. a 50‐year period, decadal cycle, and interannual cycle). The LW budget was quantified by measuring the volumes of LW inputs, accumulations, and outputs within river sections that were finally evacuated from the watershed. The study site included three unusually large but natural wood rafts in the delta of the Saint‐Jean River (SJR; Québec, Canada) that have accumulated all LW exported from the watershed for the last 50 years. We observed an increase in fluvial dynamics since 2004, which led to larger LW recruitment and a greater LW volume trapped in the river corridor, suggesting that the system is not in equilibrium in terms of the wood budget but is rather recovering from previous human pressures as well as adjusting to hydroclimatic changes. The results reveal the large variability in the LW budget dynamics during the 50‐year period and allow us to examine the eco‐hydromorphological trajectory that highlights key variables (discharge, erosion rates, bar surface area, sinuosity, wood mobility, and wood retention). Knowledge on the dynamics of these variables improves our understanding of the historical and future trajectories of LW dynamics and fluvial dynamics in gravel‐bed rivers. Extreme events (flood and ice‐melt) significantly contribute to LW dynamics in the SJR river system. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Optimization methodology for a river temperature monitoring network for the characterization of fish thermal habitat     

Anik Daigle  Arnaud Caudron  Laure Vigier  Hervé Pella 《水文科学杂志》2017,62(3):483-497

A methodology for planning an optimized river water temperature monitoring network is presented. The methodology is based on sampling of the physio-climatic variability of the region to be monitored. Physio-climatic metrics are selected to describe the study region, based on principal component analysis. The sites to be monitored are then identified based on a k-means clustering in the multidimensional space defined by the selected metrics. The methodology is validated on an existing dense water temperature network in Haute-Savoie, France. Different configurations of more or less dense network scenarios are evaluated by assessing their ability to estimate water temperature indices at ungauged locations. An optimized network containing 83 sites is found to provide satisfactory estimations for seven ecologically and biologically meaningful thermal indices defined to characterize brown trout thermal habitat.  相似文献   

Common-offset common-reflection-surface attributes estimation with differential evolution     

Tiago Barros  Renato Lopes  Rafael Krummenauer  Hervé Chauris 《Geophysical Prospecting》2019,67(8):2022-2034

Common-reflection surface is a method to describe the shape of seismic events, typically the slopes (dip) and curvature portions (traveltime). The most systematic approach to estimate the common-reflection surface traveltime attributes is to employ a sequence of single-variable search procedures, inheriting the advantage of a low computational cost, but also the disadvantage of a poor estimation quality. A search strategy where the common-reflection surface attributes are globally estimated in a single stage may yield more accurate estimates. In this paper, we propose to use the bio-inspired global optimization algorithm differential evolution to estimate all the two-dimensional common-offset common-reflection surface attributes simultaneously. The differential evolution algorithm can provide accurate estimates for the common-reflection surface traveltime attributes, with the benefit of having a small set of input parameters to be configured. We apply the differential evolution algorithm to estimate the two-dimensional common-reflection surface attributes in the synthetic Marmousi data set, contaminated by noise, and in a land field data with a small fold. By analysing the stacked and coherence sections, we could see that the differential evolution based common-offset common-reflection surface approach presented significant signal-to-noise ratio enhancement.  相似文献