A mesoscale shear convective cell observed during the C.O.A.S.T. experiment: Acoustic sounder measurements     

A. Weill  F. Baudin  C. Mazaudier  G. Desbraux  C. Klapisz  A. G. M. Driedonks  J. P. Goutorbe  A. Druilhet  P. Durand 《Boundary-Layer Meteorology》1988,44(4):359-371

A mesoscale shear convective cell was observed with a Doppler sodar and a minisodar on May 22, 1983 near the Netherland Coast. Boundary-layer modifications associated with fair weather precipitating clouds were observed and a separation is undertaken between the different scales of the perturbations. There is difficulty in estimating the turbulent dissipation rate by the inertial method in the presence of mesoscale perturbations, which suggests the need for independent computation of spatial structure functions of velocity fluctuations and spectral density of velocity fluctuations as functions of frequency to observe the relationship between wave lengths and frequencies.C.O.A.S.T.: Cooperative Experiment with Acoustic Sounding Techniques.  相似文献   

Diagenetic trends of a tertiary low-rank coal series     

Jean-Paul Boudou  Bernard Durand  Jean-Louis Oudin 《Geochimica et cosmochimica acta》1984,48(10):2005-2010

The Mahakam delta (Kalimantan, Indonesia) coals represent all the evolution stages between freshly-deposited plant/peat material, lignites and bituminous coals. The geochemical techniques used to study this coal series included elemental analysis, extraction of humic compounds, infrared spectroscopy and ¹³C nuclear magnetic resonance of the total coal.The main mechanisms of early maturation in this series are loss of oxygenated compounds, aromatisation and condensation of the organic matter. These changes, which have already been suggested for other coal series and partially reported for sedimentary organic matter, were confirmed and described in more detail for the Mahakam coal series.  相似文献   

Urban Thermodynamic Island in a Coastal City Analysed from an Optimized Surface Network     

Grégoire Pigeon  Aude Lemonsu  Nathalie Long  Joël Barrié  Valéry Masson  Pierre Durand 《Boundary-Layer Meteorology》2006,120(2):315-351

Within the framework of ESCOMPTE, a French experiment performed in June and July 2001 in the south-east of France to study the photo-oxidant pollution at the regional scale, the urban boundary layer (UBL) program focused on the study of the urban atmosphere over the coastal city of Marseille. A methodology developed to optimize a network of 20 stations measuring air temperature and moisture over the city is presented. It is based on the analysis of a numerical simulation, performed with the non-hydrostatic, mesoscale Meso-NH model, run with four nested-grids down to a horizontal resolution of 250 m over the city and including a specific parametrization for the urban surface energy balance. A three-day period was modelled and evaluated against data collected during the preparatory phase for the project in summer 2000. The simulated thermodynamic surface fields were analysed using an empirical orthogonal function (EOF) decomposition in order to determine the optimal network configuration designed to capture the dominant characteristics of the fields. It is the first attempt of application of this kind of methodology to the field of urban meteorology. The network, of 20 temperature and moisture sensors, was implemented during the UBL-ESCOMPTE experiment and continuously recorded data from 12 June to 14 July 2001. The measurements were analysed in order to assess the urban thermodynamic island spatio-temporal structure, also using EOF decomposition. During nighttime, the influence of urbanization on temperature is clear the field is characterized by concentric thermo-pleths around the old core of the city, which is the warmest area of the domain. The moisture field is more influenced by proximity to the sea and airflow patterns. During the day, the sea breeze often moves from west or south-west and consequently the spatial pattern for both parameters is characterized by a gradient perpendicular to the shoreline. Finally, in order to assess the methodology adopted, the spatial structures extracted from the simulation of the 2000 preparatory campaign and observations gathered in 2001 have been compared. They are highly correlated, which is a relevant validation of the methodology proposed. The relations between these spatial structures and geographical characteristics of the site have also been studied. High correlations between temperature spatial structure during nighttime and urban cover fraction or street aspect ratio are observed and simulated. For temperature during daytime or moisture during both daytime and nighttime these geographical factors are not correlated with thermodynamic fields spatial structures.  相似文献   

Origin of Ca in South Indian calcretes developed on metamorphic rocks     

N. Durand  S.M. Ahmad  B. Hamelin  Y. Gunnell  P. Curmi 《Journal of Geochemical Exploration》2006,88(1-3):275

Calcrete profiles developed on Precambrian silicate rocks in south peninsular India are studied and compared in terms of mineralogical, chemical and isotopic composition. The aim of this study is to determine the origin of calcium and the processes governing the development of a minor economic deposit in different geomorphic settings. The investigation integrates observations from an outcrop to a microfabric scale and reveals that the origin of calcium is local and linked with the weathering of the minerals of the surrounding rocks. The CaCO₃ precipitation occurs after vertical and lateral translocation in the slope system.  相似文献   

A new bioassay for the inspection and identification of TBT-containing antifouling paint     

Herv Gueun  Grald Thouand  Marie-Jos Durand 《Marine pollution bulletin》2009,58(11):1734-1738

Since the 1960s tributyl (TBT)-based antifouling paints are widely applied to protect ship’s hulls from biofouling. Due to its high toxicity to aquatic ecosystem most of the countries (28 nations in 2008) signed the AFS convention to control the use of harmful antifouling systems on ships. Nevertheless there is currently no simple method to control the presence of organotin in paint. In this study, we propose a bioassay based on the use of a recombinant bioluminescent bacteria to detect directly in paint the presence of TBT. We also propose a simple device as an inspection system to control the absence of organotin in the ship’s hull paint. The presence of organotin could be revealed in less than three hours.  相似文献   

Telescope and instrument robotization at Dome C     

K. G. Strassmeier  K. Agabi  L. Agnoletto  A. Allan  M. I. Andersen  W. Ansorge  F. Bortoletto  R. Briguglio  J.‐T. Buey  S. Castellini  V. Coud du Foresto  L. Dam  H. J. Deeg  C. Eiroa  G. Durand  D. Fappani  M. Frezzotti  T. Granzer  A. Grschke  H. J. Krcher  R. Lenzen  A. Mancini  C. Montanari  A. Mora  A. Pierre  O. Pirnay  F. Roncella  F.‐X. Schmider  I. Steele  J. W. V. Storey  N. F. H. Tothill  T. Travouillon  L. Vittuari  M. Weber 《Astronomische Nachrichten》2007,328(6):451-474

This article reviews the situation for robotization of telescopes and instruments at the Antarctic station Concordia on Dome C. A brain‐storming meeting was held in Tenerife in March 2007 from which this review emerged.We describe and summarize the challenges for night‐time operations of various astronomical experiments at conditions “between Earth and Space” and conclude that robotization is likely a prerequisite for continuous astronomical data taking during the 2000‐hour night at Dome C. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

The 1531 earthquake revisited: loss estimation in a historical perspective     

Luis Sá  Antonio Morales-Esteban  Percy Durand Neyra 《Bulletin of Earthquake Engineering》2018,16(10):4533-4559

  相似文献   

Integrated Hydrological Modeling of Climate Change Impacts in a Snow-Influenced Catchment     

Fabien Cochand  René Therrien  Jean-Michel Lemieux 《Ground water》2019,57(1):3-20

The potential impact of climate change on water resources has been intensively studied for different regions and climates across the world. In regions where winter processes such as snowfall and melting play a significant role, anticipated changes in temperature might significantly affect hydrological systems. To address this impact, modifications have been made to the fully integrated surface-subsurface flow model HydroGeoSphere (HGS) to allow the simulation of snow accumulation and melting. The modified HGS model was used to assess the potential impact of climate change on surface and subsurface flow in the Saint-Charles River catchment, Quebec (Canada) for the period 2070 to 2100. The model was first developed and calibrated to reproduce observed streamflow and hydraulic heads for current climate conditions. The calibrated model was then used with three different climate scenarios to simulate surface flow and groundwater dynamics for the 2070 to 2100 period. Winter stream discharges are predicted to increase by about 80, 120, and 150% for the three scenarios due to warmer winters, leading to more liquid precipitation and more snowmelt. Conversely, the summer stream discharges are predicted to fall by about 10, 15, and 20% due to an increase in evapotranspiration. However, the annual mean stream discharge should remain stable (±0.1 m³/s). The predicted increase in hydraulic heads in winter may reach 15 m and the maximum decrease in summer may reach 3 m. Simulations show that winter processes play a key role in the seasonal modifications anticipated for surface and subsurface flow dynamics.  相似文献   

Geostationary secular dynamics revisited: application to high area-to-mass ratio objects     

Fabien Gachet  Alessandra Celletti  Giuseppe Pucacco  Christos Efthymiopoulos 《Celestial Mechanics and Dynamical Astronomy》2017,128(2-3):149-181

The long-term dynamics of the geostationary Earth orbits (GEO) is revisited through the application of canonical perturbation theory. We consider a Hamiltonian model accounting for all major perturbations: geopotential at order and degree two, lunisolar perturbations with a realistic model for the Sun and Moon orbits, and solar radiation pressure. The long-term dynamics of the GEO region has been studied both numerically and analytically, in view of the relevance of such studies to the issue of space debris or to the disposal of GEO satellites. Past studies focused on the orbital evolution of objects around a nominal solution, hereafter called the forced equilibrium solution, which shows a particularly strong dependence on the area-to-mass ratio. Here, we (i) give theoretical estimates for the long-term behavior of such orbits, and (ii) we examine the nature of the forced equilibrium itself. In the lowest approximation, the forced equilibrium implies motion with a constant non-zero average ‘forced eccentricity’, as well as a constant non-zero average inclination, otherwise known in satellite dynamics as the inclination of the invariant ‘Laplace plane’. Using a higher order normal form, we demonstrate that this equilibrium actually represents not a point in phase space, but a trajectory taking place on a lower-dimensional torus. We give analytical expressions for this special trajectory, and we compare our results to those found by numerical orbit propagation. We finally discuss the use of proper elements, i.e., approximate integrals of motion for the GEO orbits.  相似文献   

Série du marégraphe de Marseille : mesures de températures de surface de la mer de 1895 à 1956 : une correction     

Jean-Claude Romano  Marie-Catherine Lugrezi  Dominique Durand  Franoise Durand-Le-Breton 《Comptes Rendus Geoscience》2010,342(12):873-880

In 2007, a daily temperature series, which has been collected from 1885 to 1967 at the Marseilles tide recorder, was published here. Upon the available information provided by the data managing office, they were considered as sea-surface temperatures. Unfortunately they were not but air temperature inside the building. In the present paper, the authors correct this error by studying the true seawater temperature series which had been dug out after the publication of the precedent paper. The study of this slightly shorter series (1895–1956) leads to close conclusions. Along these 61 years, the warming trend of the surface seawater rises to +1.6 °C, to +1.3 °C if only January to May and December are selected and +2.2 °C during the June to November period. In the first half part of the series (1895–1925), the average value of each month distributions (except January) and annual minimal (except 1956) are significantly lower than along the second (1925–1956).  相似文献