3,764 research outputs found
Estimate of surface direct radiative forcing of desert dust from atmospheric modulation of the aerosol optical depth
No full textMeasurements carried out on the island of Lampedusa, in the central Mediterranean, on 7 September 2005, show the occurrence of a quasi-periodic oscillation of aerosol optical depth, column water vapour, and surface irradiance in different spectral bands. The oscillation has a period of about 13 min and is attributed to the propagation of a gravity wave able to modify the vertical structure of the planetary boundary layer, as also confirmed by satellite images. The wave occurred during a Saharan dust event. The oscillation amplitude is about 0.1 for the aerosol optical depth, and about 0.4 cm for the column water vapour. The modulation of the downward surface irradiances is in opposition of phase with respect to aerosol optical depth and water vapour column variations. The perturbation of the downward irradiance produced by the aerosols is determined by comparing the measured irradiances with estimated irradiances at a fixed value of the aerosol optical depth, and by correcting for the effect of the water vapour in the shortwave spectral range. The direct radiative forcing efficiency, i.e., the radiative perturbation of the net surface irradiance produced by a unit of optical depth aerosol layer, is determined at different solar zenith angles as the slope of the irradiance perturbation versus the aerosol optical depth. The estimated direct surface forcing efficiency at about 60 solar zenith angle is -(181 ± 17) W m-2 in the shortwave, and -(83 ± 7) W m-2 in the photosynthetic spectral range. The estimated daily average forcing efficiencies are of about -79 and -46 W m-2 for the shortwave and photosynthetic spectral range, respectively. © 2013 Author(s)
On the systematic uncertainties in DUNE and their role in New Physics studies
No full textAbstract In the recent years experiments have established the existence of neutrino oscillations and most of the oscillation parameters have been measured with a good accuracy. The search for New Physics in neutrino oscillation will be an experimental concrete possibility in the next future. In this paper we investigate the ability of the DUNE facility to search for Non Standard Interaction (NSI) in neutrino propagation in matter, emphasizing the role of different assumptions on the shape and absolute normalization errors of both ν e and ν μ signals. We also study in detail the effects of NSI and systematics in the extraction of standard oscillation parameters
Consistency of dimensional distributions and refractive indices of desert dust measured over Lampedusa with IASI radiances
No full textIn the context of the ChArMEx campaign, we present here some results concerning the quantitative comparison between simulated and observed radiances in the presence of atmospheric desert dust, between June and July 2013 in the southern Mediterranean Basin, in the air mass above the island of Lampedusa. In particular, comparisons have been performed between radiances as observed by the Infrared Atmospheric Sounder Interferometer (IASI) and those simulated using the σ-IASI-as radiative transfer model, which takes into account aerosol extinction effect through a set of fast parameterizations. Simulations have been carried out using different sets of input complex refractive indices, which take into account the parent soils of the aerosols. Their accuracy also relies on the quality of the characterization of desert dust microphysical properties, achieved through direct measurements in the ChArMEx experiment. On the one hand, the fact that the model can ingest such a variable input proves its feasibility. On the other hand, this work goes through a direct validation of different refractive index sets for desert dust in the thermal infrared, and pursues an assessment of the sensitivity of IASI data with respect to the dimensional distribution of desert dust particles. Results show a good consistency between calculations and observations, especially in the spectral interval 800-1000g'1; further, the comparison between calculations and observations suggests that further efforts are needed to better characterize desert dust optical properties in the shortwave (above 2000g'1). Whatever the case, we show that it is necessary to properly tune the refractive indices according to the geographical origin of the observed aerosol. © Author(s) 2017
Probing source and detector nonstandard interaction parameters at the DUNE near detector
No full textWe investigate the capability of the DUNE near detector (ND) to constrain nonstandard interaction parameters (NSIs) describing the production of neutrinos and their detection . We show that the DUNE ND is able to reject a large portion of the parameter space allowed by DUNE far detector analyses and to set the most stringent bounds from accelerator neutrino experiments on for wide intervals of the related phases. We also provide simple analytic understanding of our results as well as a numerical study of their dependence on the systematic errors, showing that the DUNE ND offers a clean environment to study source and detector NSIs
Predicting leptonic CP violation in the light of Daya Bay result on theta13
No full textIn the light of the recent Daya Bay result , we reconsider the model presented in Meloni et al. (J. Phys. G 38:015003, 2011), showing that, when all neutrino oscillation parameters are taken at their best fit values of Schwetz et al. (New J. Phys. 10:113011, 2008) and where , the predicted values of the CP phase are δ≈±π/4
Exploring new physics from ν events in OPERA
No full textWe analyze in details the impact of the events seen in the
OPERA experiment in constraining the Non Standard Interaction parameter
affecting neutrino propagation in matter and the
allowed parameter space of models with one sterile neutrino of the type
High Hydrostatic Pressures (HHP) processing technology as a novel control method of Listeria monocytogenes occurrence in Mediterranean-style dry fermented sausages
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