Search results for "Ocean"
showing 10 items of 2919 documents
Near-field spectroscopy of low-loss waveguide integrated microcavities
2006
International audience; A scanning near-field spectroscopy method is used to observe loss reduction and Q-factor enhancement due to transverse-mode profile matching within photonic-crystal microcavities. Near-field measurements performed directly on cavity modes are compared with three-dimensional calculations and quantitative agreement is observed. (c) 2006 American Institute of Physics.
Geometric Optimal Control of Simple Quantum Systems
2011
International audience
Titan's 3-micron spectral region from ISO high-resolution spectroscopy
2006
Abstract The near-infrared spectrum of Titan, Saturn's largest moon and one of the Cassini/Huygens' space mission primary targets, covers the 0.8 to 5 micron region in which it shows several weak CH 4 absorption regions, and in particular one centered near 2.75 micron. Due to the interference of telluric absorption, only part of this window region (2.9–3.1 μm) has previously been observed from the ground [Noll, K.S., Geballe, T.R., Knacke, R., Pendleton, F., Yvonne, J., 1996. Icarus 124, 625–631; Griffith, C.A., Owen, T., Miller, G.A., Geballe, T., 1998. Nature 395, 575–578; Griffith, C.A., Owen, T., Geballe, T.R., Rayner, J., Rannou, P., 2003. Science 300, 628–630; Geballe, T.R., Kim, S.J.…
First results of the Piton de la Fournaise STRAP 2015 experiment: multidisciplinary tracking of a volcanic gas and aerosol plume
2016
Abstract. The STRAP (Synergie Transdisciplinaire pour Répondre aux Aléas liés aux Panaches volcaniques) campaign was conducted in 2015 to investigate the volcanic plumes of Piton de La Fournaise (La Réunion, France). For the first time, measurements at the local (near the vent) and at the regional scales around the island were conducted. The STRAP 2015 campaign has become possible thanks to a strong cross-disciplinary collaboration between volcanologists and meteorologists. The main observations during four eruptive periods (85 days) are summarized. They include the estimates of SO2, CO2 and H2O emissions, the altitude of the plume at the vent and over different areas of La Réunion Island, …
Error propagation from line parameters to spectra simulations. Illustration on high temperature methane.
2010
Astrophysical investigations generally need both complete and accurate spectroscopic databases. Despite continuous efforts in experimental and theoretical spectroscopic investigations, the lack of data in some spectral regions of interest is one of the main limitation of the presently available spectroscopic databases. Unfortunately information about missing data relevant to specific experimental conditions is rarely directly accessible from spectroscopic databases (focusing naturally on available data). Such information relies essentially on theoretical investigations which are equally limited to the present state of the art of modelling. The purpose of the talk is to show how multi-resolu…
Multi-resolution error analysis of predicted absorption coefficients. Method and computer implementation. Application to the IR spectrum of methane a…
2009
A general method for the estimation of the confidence interval of molecular absorption coefficients is presented. It combines statistical numerical experiments with analytical calculations. The method uses line parameter predictions (position and intensity) with known estimated uncertainties. The propagation of errors from line parameters to absorption coefficients or cross-sections are analyzed in detail as a function of the resolution. This work is especially intended to provide expert information for applications requiring theoretical predictions for which the present state of the art of line by line high-resolution modeling is not accurate enough to meet the experimental precision. As a…
The STDS Dijon system : Present status and prospects.
2009
The Dijon spectroscopy group has developed powerful techniques based on group theory and tensorial formalism in order to analyze and simulate absorption and Raman spectra of molecules with various symmetries. Software packages and databases implementing these tools have been created [1]. Compared to the widely used spectroscopic databases (HITRAN, GEISA), these packages, with their XTDS common interface [2], are primarily devoted to the calculation of line parameters and spectra from a database of model parameters. Future developments include improved fitting algorithms, inclusion of C3v symmetric tops, rovibronic couplings, uncertainty estimates. Moreover, calculated line lists will be acc…
Global analysis of 13CH4 lines in the 0 - 3200 cm-1 region
2007
We have carried out new measurements of infrared spectra of the spherical top molecules 12CH4, 13CH4 and 12CD4 at low – (80K) and room temperature (298K). Spectra were recorded at very high resolution (0.0027 cm−1 around 2900 cm−1) using the Z¨urich prototype Bruker 125 spectrometer (ZP 2001)3 combined with a low temperature cooling cell. Due to low temperature, the Doppler full width at half maximum (0.0045 cm−1 around 2900 cm−1 at 80K) was reduced by a factor of 1.91. We report the analysis of two low – and six room temperature spectra and present the global analysis of 4000 (2000 newly assigned) 13CH4-transitions from 0 up to 3200 cm−1. The results are compared to previous work. In the p…
Theoretical background and preliminary results of the global modeling of the lower three polyads of PH3 covering the 3 to 10 µm spectral region
2007
A recent study reported in 2006 provided an empirical database of PH3 (line positions and intensities) in the 3 μm region. The study was based experimentally on FTIR spectra recorded at Kitt Peak at various optical densities and theoretically on single state fits of features assigned using the ground state combination differences method. The need for a complete analysis of the octad was underlined in order to account for the complex interactions which is expecially important for intensity modeling. The polyad pattern of the PH3 molecule presents close similarities with those of spherical top molecules (like CH4), although the symmetry degeneracies are reduced. The simultaneous analysis of t…
Current status of the global modeling of the lower three polyads of PH3 (position and intensities)
2008
As part of extensive efforts to support remote sensing of Jupiter and Saturn many works have been devoted to the high-resolution infrared spectrum of phosphine. However, at present, the line parameters of phosphine (positions and intensities) in the 3 \mu m region rely essentially on the empirical database reported in 2006. So far, only weakly interacting features could be fitted using isolated band models while strongly interacting states were left out. The goal of the present work is to achieve a comprehensive modeling of the lower three polyads of the molecule. The simultaneous analysis of the dyad, pentad and octad of PH_3 has been undertaken using an effective hamiltonian in the form o…