172 research outputs found
Snow satellite images for calibration of snow dynamic in a continuous distributed hydrological model
International audienceThe snow accumulation and melt processes are well known to play an important role on the river flow regime, in particular this is enhanced for basin with complex topography where the snow dynamic is strongly affected by hillslope exposition. This paper presents a simplified numerical model for snow dynamic simulation based on air temperature thresholds that rule the snow melt and accumulation processes implemented into a continuous distributed hydrological model for hydrograph simulations at basin scale. The possibility to calibrate these temperature thresholds from snow cover maps derived from NOAA satellite images is discussed. Snow covered pixels are classified according to a procedure based on aspect and elevation of each pixel, that allows to identify snow covered pixels also in shadowed areas. Snow model performance is proved at local and basin scale. The former shows a good agreement between modelled snow dynamic and observed snow height data at the Antrona station in the Toce basin; the latter shows agreement between observed and simulated hydrographs for the three gauge stations of Toce, Ticino and Maggia rivers
Elevation based correction of snow coverage retrieved from satellite images to improve model calibration
reserved4The most widely used method for snow dynamic simulation relies on temperature index approach, that makes snow melt and accumulation processes depend on air temperature related parameters. A recently used approach to calibrate these parameters is to compare model results with snow coverage retrieved from satellite images. In area with complex topography and heterogeneous land cover, snow coverage may be affected by the presence of shaded area or dense forest that make pixels to be falsely classified as uncovered. These circumstances may have, in turn, an influence on calibration of model parameters.
In this paper we propose a simple procedure to correct snow coverage retrieved from satellite images. We show that using raw snow coverage to calibrate snow model may lead to parameter values out of the range accepted by literature, so that the timing of snow dynamics measured at two ground stations is not correctly simulated. Moreover, when the snow model is implemented into a continuous distributed hydrological model, we show that calibration against corrected snow coverage reduces the error in the simulation of river flow in an Alpine catchment.C. Corbari; G. Ravazzani; J. Martinelli; M. ManciniCorbari, Chiara; Ravazzani, Giovanni; J., Martinelli; Mancini, Marc
Innes: Security Bonds
Risk in society is a pertinent concept of late modernity. Most elements of our social and interpersonal lives are in some way linked to concerns about safety, security and fear of harm. As a consequence, we spend a great deal of time engaged in emotional, physical and economic processes that facilitate our safety. Whether this be through purchasing anti-theft devices, or subscribing to self-defense training courses; participating in neighbourhood-watch schemes or altering our behavior to prevent susceptibility to victimization, all demonstrate an inherent pre-occupation with risk and perceived danger. The work presented in this paper offers an in-depth socio-criminological analysis focusing on the issue of citizens insecurity, and proposes an original interpretative paradigm emerging from findings on the INNES (Intimate Neighborhood Strengthening) European Project. A presentation of the idiographic and nomothetic motivations and conditions influencing and predicting social fears and insecurities over the last two decades is discussed, with the presentation of the new interpretative model, 'Social Cobweb Theory'. This model focuses on solidarity and on the strengthening of intimate neighborhood bonds and argues that these aforementioned concepts function as an effective approach in lowering citizens' perceptions of individual insecurities and risk
Proximal-sensing-powered modelling of energy-water fluxes in a vineyard: A spatial resolution analysis
Spatial resolution is a key parameter in energy–water surface flux modelling. In this research, scale effects are analyzed on fluxes modelled with the FEST-EWB model, by upscaling both its inputs and outputs separately. The main questions are: (a) if high-resolution remote sensing images are necessary to accurately model a heterogeneous area; and (b) whether and to what extent low-resolution modelling provides worse/better results than the upscaled results of high-resolution modelling. The study area is an experimental vineyard field where proximal sensing images were obtained by an airborne platform and verification fluxes were measured via a flux tower. Modelled fluxes are in line with those from alternative energy-balance models, and quite accurate (NSE = 0.78) with respect to those measured in situ. Field-scale evapotranspiration has resulted in both the tested upscaling approaches (with relative error within ±30%), although fewer pixels available for low-resolution calibration may produce some differences. When working at low resolutions, the model has produced higher relative errors (20% on average), but is still within acceptable bounds. This means that the model can produce high-quality results, partially compensating for the loss in spatial heterogeneity associated with low-resolution images
Thermal poling of glass modified by femtosecond irradiation
Thermal poling of silica glass modified by femtosecond laser irradiation is demonstrated. Increase of second-harmonic generation in the irradiated regions is observed. This enhancement is interpreted in terms of structural modifications in silica glass that make the poling process more efficient. Evidence of a change in the distribution of the electrostatic field frozen in glass during poling is obtained. This technique is used for (2) grating fabrication
Searching for the γ decay from the near-neutron threshold 2+ state in 14C: A probe of collectivization phenomena in light nuclei
The γ decay from the 2+2 near-threshold resonance in 14C, located 142 keV above the neutron emission threshold, was searched for in a fusionevaporation experiment at Argonne National Laboratory with the GODDESS setup, comprising the GRETINA γ-ray spectrometer coupled to the ORRUBA charged particle detector. The Shell Model Embedded in the Continuum predicts a significant enhancement of the 2+2 → 0 transition probability, owing to a collectivization of the
near-threshold state. The corresponding γ branch is expected to be of the order of 5 × 10−5, which is comparable with the sensitivity of this experiment
Search for the γ decay of the narrow near-threshold proton resonance in 11B
The γ decay of the elusive narrow, near-threshold proton resonance in 11B was investigated at Laboratori Nazionali di Legnaro (INFN) in a particle-γ coincidence experiment, using the 6Li(6Li,pγ) fusion-evaporation reaction and the GALILEO-GALTRACE setup. No clear signature was found for a possible E1 decay to the 1/2
, first-excited state of 11B, predicted by the Shell Model Embedded in the Continuum (SMEC) with a branching of
with respect to the dominant particle-decaying modes. The statistical analysis of the γ-ray spectrum provided an average upper limit of
for this γ-ray branching, with a global significance of 5σ. On the other hand, by imposing a global confidence level of 3σ, a significant excess of counts was observed for E
keV, corresponding to a resonance energy of 11429(20) keV (namely 200(20) keV above the proton separation energy of 11B) and a γ-ray branching of
. This result is compatible with the SMEC calculations, potentially supporting the existence of a near-threshold proton resonance in 11B.This work was supported by the Italian Istituto Nazionale di Fisica Nucleare, the Polish National Science Centre, Poland under research project No.
2020/39/D/ST2/03443
, the PRIN2017 call for funding, under the project
2017P8KMFT
CTADIR from the Italian Ministry of Education, University and Research, the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, grant no.
2020R1A6A3A03039081
, the MCIN/AEI/10.13039/501100011033, Spain with grant
PID2020-118265GB-C42
, by Generalitat Valenciana, Spain with grant
CIAPOS/2021/114
and by the EU FEDER funds.Departamento de FÃsica Aplicad
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