1,721,260 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)
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
High Hydrostatic Pressures (HHP) processing technology as a novel control method of Listeria monocytogenes occurrence in Mediterranean-style dry fermented sausages
No full textOn 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
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
Hygienic and commercial issues related to sea cucumber illegal fishing and processing in the Mediterranean: a case study on over-exploitation in Italy between 2015 and 2017
No full textProbing source and detector nonstandard interaction parameters at the DUNE near detector
Full text linkWe 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
Effects of the tropicalization on the Mediterranean Fishery sector: state of the art and analysis of the commercial and sanitary issues
No full textSensitivity of the atmospheric temperature profile to the aerosol absorption in the presence of dust
No full textRadiative transfer simulations in the shortwave (SW) and longwave (LW) spectral regions have been carried out to investigate the time evolution of the atmospheric heating/cooling rates and their influence on the temperature profiles under different vertical distributions of the aerosol absorption. The case study is based on measurements made at Rome, Italy, on 20 June 2007, when a dust layer was present above the urban boundary layer (BL) and the column aerosol optical depth at 550 nm was about 0.37. Column-integrated aerosol optical depth and single scattering albedo, as well as vertical profiles of aerosol extinction and meteorological variables have been derived from observations and used in the simulations. Different profiles of the aerosol absorption are considered by varying the absorption of the BL aerosols and of the desert dust, without changing the overall columnar properties. Three scenarios have been considered, with absorbing (ABL) or scattering (SBL) particles in the BL, and with a vertically homogeneous case (HL), which is taken as the reference. Calculations show that, for the selected case, about 25% of the SW heating is offset by the LW cooling within the dust layer. Different longwave/all-wave contributions are observed in the BL, depending on the BL aerosol absorption. Changes of atmospheric temperature induced by aerosol-radiation interactions only, have been investigated, while interactions with the surface through changes of the latent and sensible heat flux have been neglected. The evolution of temperature is similar for the three scenarios within the dust layer, with a daytime increase and a smaller nighttime decrease. After 24 h, the increase of the atmospheric temperature due to the aerosol radiative processes is about 1 K. In the BL, the increase of temperature is strongly dependent on the aerosol absorption capability. The oscillatory behaviour of the temperature with time in the dust layer, and the different evolution in the BL are expected to affect the temperature vertical gradient and may influence related processes
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