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11.
Assessment of the coastal dynamics in a nested zoom and feedback on the boundary current: the North-Western Mediterranean Sea case 总被引：1，自引：1，他引：0
The Northern Current (hereafter NC), the major current in the North-Western Mediterranean (hereafter NWM) basin, has been largely investigated in the litterature for its mesoscale features. Its behaviour in the Var region can strongly condition the downstream flow along the Gulf of Lions shelf and Spain coast, making this zone a key area. However, the sub-mesoscale dynamics of the area and its potential impacts on the rest of the flow are not well known. This work reveals the potential interest of better simulating high-resolution dynamics in a restricted area and how this could improve the circulation representation in a larger area. To address this question, a very high resolution configuration (1/192°) nested in an already existing high-resolution configuration (1/64°) has been developed, using the NEMO model. Comparisons with observations show that the very high-resolution changes only weakly the mean NC characteristics but can significantly modify individual mesoscale events such as eddies and meanders occurring in the zoomed area. Furthermore, the coastal dynamics and episodic intrusions of a NC secondary branch inside a semi-enclosed bay appear to be significantly enhanced. In a second stage, the assessment of the feedback of this improved dynamics on the regional mesoscale dynamics is shown, this being allowed by the two-way coupling option of the embedded configuration using AGRIF. 相似文献
12.
Amandine Bordon Odile Peyron Anne-Marie Lzine Simon Brewer Eric Fouache 《Quaternary International》2009,200(1-2):19
High-temporal resolution analysis of pollen records from Lake Maliq (Albania) provides quantitative estimates of monthly temperature and precipitation changes since the last deglaciation. The climate parameters were estimated using the best modern analogue technique with an updated modern pollen-climate database composed of 2748 surface samples. The record shows two main cooling phases in the Maliq area (the Oldest and Younger Dryas) and a cooling event around 8200 years, which suggests that the forcing factors driving climate variations in the North Atlantic area since the Last Glacial period also extended their influence into the Mediterranean area. The Oldest and Younger Dryas are also characterized by an arid climate and a change in the seasonality of precipitation: the summer precipitation tends to be greater during the cooling phases than during the temperate periods. The Holocene climate is relatively stable and the values of each parameter reach their modern levels, except for an arid event between 8300 and 8100 cal BP. 相似文献
13.
A. Bajat O. Godet J.-L. Atteia S. Maestre D. Rambaud V. Waegebaert C. Amoros S. Bordon S. Delaigue M. Galliano B. Houret K. Lacombe P. Mandrou W. Marty R. Pons P. Ramon 《Experimental Astronomy》2018,46(2):337-356
French (CNES) and Chinese (CNSA) space agencies collaborate to build the SVOM (Space-based multi-band Variable Object Monitor) mission due to be launched in 2021 to study gamma-ray bursts and high-energy transients. The SVOM prime instrument, ECLAIRs, will detect and localize GRBs autonomously as well as provide a spectral and temporal characterization of the GRB prompt emission. ECLAIRs is expected to detect around 200 GRBs during the 3 year nominal lifetime of the mission. ECLAIRs is a wide-field (\(\sim 2 \text {sr}\)) coded mask camera with a detection plane made of 8 independent sectors of 800 Schottky CdTe detectors working in the 4-150 keV energy range. Each sector is connected to independent readout electronics. In this paper, we focus on the study of the temporal performance and we estimate how dead time will affect bright transient lightcurves. We discuss the analytical model based on simulations over a large range of source count rates on a dedicated test bench. We show that dead time will not significantly affect ECLAIRs data, even for the brightest GRBs (3.7% of lost counts for a count rate of 105 counts.s??1 over the detection plane in the energy range 4?150 keV) and our model can nicely correct the parts of the lightcurves which are the most affected by dead time effects for very bright GRBs. 相似文献
14.
15.
Modelling for anchovy recruitment studies in the Gulf of Lions (Western Mediterranean Sea) 总被引：4，自引：4，他引：0
Anchovy (Engraulis encrasicolus) is an important commercial species and one of the most abundant pelagic fish in the Gulf of Lions and the Catalan Sea. The
factors influencing its recruitment are crucial to fisheries and ecological research. Among those factors transport of larvae
by hydrodynamics (currents) is important because it determines whether the organisms can reach areas favourable to recruitment
or are dispersed. Therefore, the first step in anchovy recruitment modelling is to simulate North-western Mediterranean Sea
circulation. Several years (2001–2008) of hydrodynamics were simulated with the MARS-3D code. The resulting simulated currents
and salinity are used by Lagrangian tool, Ichthyop, to transport anchovy eggs and larvae to the Western Mediterranean Sea.
The aim of this study is to understand the main hydrodynamic processes that control anchovy transport and the effects of diel
vertical migration on the transport and final distribution of anchovy. 相似文献
16.
Pascal Bonnefond Pierre Exertier Olivier Laurain Amandine Guillot Nicolas Picot Mathilde Cancet 《Marine Geodesy》2015,38(3):171-192
The geodetic Corsica site was set up in 1998 in order to perform altimeter calibration of the TOPEX/Poseidon (T/P) mission and subsequently, Jason-1 and OSTM/Jason-2. The scope of the site was widened in 2005 in order to undertake the calibration of the Envisat mission and most recently of SARAL/AltiKa. Here we present the first results from the latter mission using both indirect and direct calibration/validation approaches. The indirect approach utilizes a coastal tide gauge and, as a consequence, the altimeter derived sea surface height (SSH) needs to be corrected for the geoid slope. The direct approach utilizes a novel GPS-based system deployed offshore under the satellite ground track that permits a direct comparison with the altimeter derived SSH. The advantages and disadvantages of both systems (GPS-based and tide gauges) and methods (direct or indirect) will be described and discussed. Our results for O/IGD-R data show a very good consistency for these three kinds of products: their derived absolute SSH biases are consistent within 17 mm and their associated standard deviation ranges from 31 to 35 mm. The AltiKa absolute SSH bias derived from GPS-zodiac measurement using the direct method is ?54 ±10 mm based on the first 13 cycles. 相似文献
17.
Amplification of the storm surges in shallow waters of the Pertuis Charentais (Bay of Biscay,France) 总被引：1，自引：1，他引：0
The Pertuis Charentais are shallow coastal embayments formed by the islands of Oleron and Re in the north-eastern Bay of Biscay.
The low-lying coasts of the Pertuis Charentais are susceptible to extensive flooding caused by the storm surges generated
in the North Atlantic. Numerical modelling of the 24 October 1999 surge event is performed in the present study in order to
elucidate the impact of the wind-wave-tide-surge interactions on the surge propagation in the Pertuis Charentais. A 2D numerical
model is constructed to simulate the wave and tide-surge propagation on a high-resolution finite-element grid by using the
TELEMAC and TOMAWAC software. The effect of the wave-induced enhancement on the sea surface drag and on the bottom friction
is evaluated by using the models of Janssen (1991) and Christoffersen and Jonsson (1985), respectively. The radiation stress is estimated by employing the approach of Longuet-Higgins and Stewart (1964). It is demonstrated that the peak surge in the night on 23–24 October has been amplified inside the Pertuis Charentais by
about 20 cm due to the wind-wave interactions with the tide-surge currents. These interactions are strongest at the entrance
to the Pertuis Charentais where the sea surface drag coefficient is significantly increased by the wind-wave coupling. The
effect of the wave-tide-surge interactions is large enough to be included in the flood forecasting systems of this region. 相似文献
18.
Emissions from the production of iron and steel could constitute a significant share of a 2°C global emissions budget (around 19% under the IEA 2DS scenario). They need to be reduced, and this could be difficult under nationally based climate policy approaches. We compare a new set of nationally based modelling (the Deep Decarbonization Pathways Project) with best practice and technical limit benchmarks for iron and steel and cement emissions. We find that 2050 emissions from iron and steel and cement production represent an average 0.28?tCO2 per capita in nationally based modelling results, very close to the technical limit benchmark of 0.21?tCO2 per capita, and over 2.5 times lower than the best practice benchmark of 0.72?tCO2 per capita. This suggests that national projections may be overly optimistic about achievable emissions reductions in the absence of global carbon pricing and an international research and development effort to develop low emissions technologies for emissions-intensive products. We also find that equal per capita emissions targets, often the basis of proposals for how global emissions budgets should be allocated, would be inadequate without global emissions trading. These results show that a nationally based global climate policy framework, as has been confirmed in the Paris Agreement, could lead to risks of overshooting global emissions targets for some countries and carbon leakage. Tailored approaches such as border taxes, sectoral emissions trading or carbon taxes, and consumption-based carbon pricing can help, but each faces difficulties. Ultimately, global efforts are needed to improve technology and material efficiency in emissions-intensive commodities manufacturing and use. Those efforts could be supported by technology standards and a globally coordinated R&D effort, and strengthened by the adoption of global emissions budgets for emissions-intensive traded goods.Policy relevanceThis article presents new empirical findings on global iron and steel and cement production in a low-carbon world economy, demonstrates the risks associated with a nationally based global climate policy framework as has been confirmed in the Paris Agreement, and analyses policy options to deal with those risks. 相似文献
19.
Spatial variability in organic material sinking export in the Hudson Bay system,Canada, during fall 总被引：1，自引：0，他引：1
Amandine Lapoussière Christine Michel Michel Gosselin Michel Poulin 《Continental Shelf Research》2009
Spatial variations in the sinking export of organic material were assessed within the Hudson Bay system (i.e., Hudson Bay, Hudson Strait and Foxe Basin) during the second oceanographic expedition of ArcticNet, on board the CCGS Amundsen in early fall 2005. Sinking fluxes of particulate organic material were measured using short-term free-drifting particle interceptor traps deployed at 50, 100 and 150 m for 8–20 h at eight stations. Measurements of chlorophyll a (chl a), pheopigments (pheo), particulate organic carbon (POC), biogenic silica (BioSi), protists, fecal pellets and bacteria were performed on the collected material. In parallel, sea surface salinity and temperature were determined at 121 stations in the Hudson Bay system. Three hydrographic regions presenting different sedimentation patterns were identified based on average surface salinity and temperature. Hudson Strait was characterized by a marine signature, with high salinity (average=32.3) and low temperature (average=2.1 °C). Eastern Hudson Bay was strongly influenced by river runoff and showed the lowest average salinity (26.6) and highest average temperature (7.6 °C) of the three regions. Western Hudson Bay showed intermediate salinity (average=29.4) and temperature (average=4.4 °C). Sinking fluxes of total pigments (chl a+pheo: 3.37 mg m−2 d−1), diatom-associated carbon (19.8 mg m−2 d−1) and BioSi (50.2 mg m−2 d−1) at 50 m were highest in Hudson Strait. Eastern Hudson Bay showed higher sinking fluxes of total pigments (0.52 mg m−2 d−1), diatom-associated carbon (3.29 mg m−2 d−1) and BioSi (36.6 mg m−2 d−1) compared to western Hudson Bay (0.19, 0.05 and 7.76 mg m−2 d−1, respectively). POC sinking fluxes at 50 m were low and relatively uniform throughout the Hudson Bay system (50.0–76.8 mg C m−2 d−1), but spatial variations in the composition of the sinking organic material were observed. A large part (37–78%) of the total sinking POC was unidentifiable by microscopic observation and was qualified as amorphous detritus. Considering only the identifiable material, the major contributors to the POC sinking flux were intact protist cells in Hudson Strait (28%), fecal pellets in eastern Hudson Bay (52%) and bacteria in western Hudson Bay (17%). A significant depth-related attenuation of the POC sinking fluxes (average loss between 50 and 150 m=32%) and a significant increase in the BioSi:POC ratio (average increase between 50 and 150 m=76%) were observed in Hudson Strait and eastern Hudson Bay. For all other sinking fluxes and composition ratios, we found no statistically significant difference with depth. These results show that during fall, the sinking export of total POC from the euphotic zone remained fairly constant throughout the Hudson Bay system, whereas other components of the organic sinking material (e.g., chl a, BioSi, fecal pellets, protist cells) showed strong spatial variations. 相似文献
20.
Marrel Amandine Perot Nadia Mottet Clémentine 《Stochastic Environmental Research and Risk Assessment (SERRA)》2015,29(3):959-974
Stochastic Environmental Research and Risk Assessment - To evaluate the consequences on human health of radionuclide releases in the environment, numerical simulators are used to model the... 相似文献