Validation of ADEOS-II GLI ocean color products using in-situ observations     

Hiroshi Murakami  Kosei Sasaoka  Kohtaro Hosoda  Hajime Fukushima  Mitsuhiro Toratani  Robert Frouin  B. Greg Mitchell  Mati Kahru  Pierre-Yves Deschamps  Dennis Clark  Stephanie Flora  Motoaki Kishino  Sei-Ichi Saitoh  Ichio Asanuma  Akihiko Tanaka  Hiroaki Sasaki  Katsumi Yokouchi  Yoko Kiyomoto  Hiroaki Saito  Cécile Dupouy  Absornsuda Siripong  Satsuki Matsumura  Joji Ishizaka 《Journal of Oceanography》2006,62(3):373-393

The Global Imager (GLI) aboard the Advanced Earth Observing Satellite-II (ADEOS-II) made global observations from 2 April 2003 to 24 October 2003. In cooperation with several institutes and scientists, we obtained quality controlled match-ups between GLI products and in-situ data, 116 for chlorophyll-a concentration (CHLA), 249 for normalized water-leaving radiance (nLw) at 443 nm, and 201 for aerosol optical thickness at 865 nm (Tau_865) and Angstrom exponent between 520 and 865 nm (Angstrom). We evaluated the GLI ocean color products and investigated the causes of errors using the match-ups. The median absolute percentage differences (MedPD) between GLI and in-situ data were 14.1–35.7% for nLws at 380–565 nm, 52.5–74.8% nLws at 625–680 nm, 47.6% for Tau_865, 46.2% for Angstrom, and 46.6% for CHLA, values that are comparable to the ocean-color products of other sensors. We found that some errors in GLI products are correlated with observational conditions; nLw values were underestimated when nLw at 680 nm was high, CHLA was underestimated in absorptive aerosol conditions, and Tau_865 was overestimated in sunglint regions. The error correlations indicate that we need to improve the retrievals of the optical properties of absorptive aerosols and seawater and sea surface reflection for further applications, including coastal monitoring and the combined use of products from multiple sensors.  相似文献   

Determination of geologic strain using randomly oriented strain markers of any shape     

Pierre-Yves F. Robin 《Tectonophysics》1977,42(1):T7-T16

Strain markers are geologic bodies within a rock which, during the deformation of that rock, have retained their identity but did not differ from their surrounding material in their mechanical behaviour. In sections they appear as closed contours. If it can be assumed that there was no preferred orientation of the markers, the axial-strain ratio in a planar section can be determined. Two lines are drawn through the centre of each marker, parallel respectively to the two axes of the sectional strain ellipse. If aj and cj are the segments defined by the intersection of these two lines with the contour of a marker j, then the axial-strain ratio is the logarithmic average of all aj/cj. As shown in an example, this method can also be used if the markers are ellipsoids. A statistical test of initial isotropy is proposed for this special case.  相似文献   

The rupture process of the Armenian earthquake from broad-band teleseismic body wave records     

H. Haessler  A. Deschamps  H. Dufumier  H. Fuenzalida  A. Cisternas 《Geophysical Journal International》1992,109(1):151-161

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On the thermodynamics of pressure solution—interaction between chemical and mechanical forces: a discussion     

F. Robin Pierre-Yves 《Geochimica et cosmochimica acta》1978,42(3):333-334

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Landslide hazard assessment based on Bayesian optimization–support vector machine in Nanping City,China     

Xie  Wei  Nie  Wen  Saffari  Pooya  Robledo  Luis F.  Descote  Pierre-Yves  Jian  Wenbin 《Natural Hazards》2021,109(1):931-948

Natural Hazards - Landslide hazard assessment is critical for preventing and mitigating landslide disasters. The tuning of hyperparameters is of great importance to achieve better accuracy in a...  相似文献   

Cyclic and creep combination effects on the long-term undrained behavior of overconsolidated clay     

Han  Jian  Yin  Zhen-Yu  Dano  Christophe  Hicher  Pierre-Yves 《Acta Geotechnica》2021,16(4):1027-1041

Acta Geotechnica - Soft soil subjected to cyclic loading typically exhibits an increase in excess pore pressure under undrained condition which brings the soil to an overconsolidated state. Then,...  相似文献   

Seismic response of Beirut (Lebanon) buildings: instrumental results from ambient vibrations   总被引：1，自引：1，他引：0  

Christelle Salameh  Bertrand Guillier  Jacques Harb  Cécile Cornou  Pierre-Yves Bard  Christophe Voisin  Armand Mariscal 《Bulletin of Earthquake Engineering》2016,14(10):2705-2730

Resonance period is a key parameter in the seismic design of a structure, thus dynamic parameters of buildings in Beirut (Lebanon) were investigated based on ambient vibration method for risk and vulnerability assessment. Lebanon is facing high seismic hazard due to its major faults, combined to a high seismic risk caused by dense urbanization in addition to the lack of a seismic design code implementation. For this study, ambient vibration recordings have been performed on 330 RC buildings, period parameters extracted and statistically analyzed to identify correlations with physical building parameters (height, horizontal dimensions, age) and site characteristics (rock sites or soft sites). The study shows that (1) the building height or number of floors (N) is the primary statistically robust parameter for the estimation of the fundamental period T; (2) the correlation between T and N is linear and site dependent: T ≈ N/23 for rock sites and N/18 for soft sites; (3) the measured damping is inversely proportional to the period: the taller the building the lower is the damping; (4) a significant overestimation of the period exists in current building codes. However part of the large discrepancy with building code recommendations may be due to the very low level of loading.  相似文献   

Modeling the effect of wetting on the mechanical behavior of crushable granular materials     

Carlos Ovalle  Pierre-Yves Hicher 《地学前缘(英文版)》2020,(2):487-494

It is well known that the compressibility of crushable granular materials increases with the moisture content,due to the decrease of particle strength in a humid environment.An existing approach to take into account the effect of grain breakage in constitutive modeling consists in linking the evolution of the grain size distribution to the plastic work.But how the material humidity can affect this relationship is not clear,and experimental evidence is quite scarce.Based on compression tests on dry and saturated crushable sand recently reported by the present authors,a new non-linear relationship is proposed between the amount of particle breakage and the plastic work.The expression contains two parameters:(1)a material constant dependent on the grain characteristics and(2)a constant depending on the wetting condition(in this study,dry or saturated).A key finding is that the relationship does not depend on the stress path and,for a given wetting condition,only one set of parameters is necessary to reproduce the results of isotropic,oedometric,and triaxial compression tests.The relationship has been introduced into an elastoplastic constitutive model based on the critical state concept with a double yield surface for plastic sliding and compression.The breakage ratio is introduced into the expression of the elastic stiffness,the critical state line and the hardening compression pressure.Incremental stress-strain computations with the model allow the plastic work to be calculated and,therefore,the evolution of particle crushing can be predicted through the proposed non-linear relationship and reintroduced into the constitutive equations.Accurate predictions of the experimental results in terms of both stress-strain relationships and breakage ratio were obtained.  相似文献   

A detailed study of the Gagua Ridge: A fracture zone uplifted during a plate reorganisation in the Mid-Eocene   总被引：2，自引：0，他引：2  

Deschamps  Anne E.  Lallemand  Serge E.  Collot  Jean-Yves 《Marine Geophysical Researches》1998,20(5):403-423

Recent multibeam bathymetric and geophysical data recorded in the West Philippine Basin, east of Taiwan, reveal new information on the structure and the tectonic origin of the oceanic Gagua Ridge. This linear, 300 km-long, 4 km-high, north-south-trending ridge, is being subducted beneath the Ryukyu Trench along 123° E. This basement high separates two basins of different ages. Its summit is marked by two crests and an axial valley. A map of the basement top shows the region of the ridge to be composed of a set of linear and parallel ridges and troughs. All these elements suggest that the development of the ridge, and its surroundings, has been influenced by strike-slip deformation. Nevertheless, the height of the ridge indicates also an important compressive component in the deformation. Gravity models across the ridge show local compensation with a crustal root, indicating that an overthickening of the crust occurred when it was young and thus more easily deformable. This idea is strengthened with flexural modeling of the lithosphere that bends under the load of the ridge, indeed it indicates that the high probably formed when the underlying lithosphere was young. We interpret the Gagua Ridge as a fracture zone transverse ridge uplifted during a transpressive episode along a north-south -trending fracture zone in the middle Eocene time, if we accept Hilde and Lee's (1984) model of magnetic lineations. This tectonic event could be contemporaneous with a change of the pole of rotation of the West Philippine Basin which occurred about 43/45 Ma ago.  相似文献   

Inversion of two-dimensional numerical convection experiments for a fluid with a strongly temperature-dependent viscosity     

Frédéric Deschamps  Christophe Sotin 《Geophysical Journal International》2000,143(1):204-218

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