MOCRA: a Monte Carlo code for the simulation of radiative transfer in the atmosphere.

This paper describes the radiative transfer model (RTM) MOCRA (MOnte Carlo Radiance Analysis), developed in the frame of DOAS (Differential Optical Absorption Spectroscopy) to correctly interpret remote sensing measurements of trace gas amounts in the atmosphere through the calculation of the Air Mass Factor. Besides the DOAS-related quantities, the MOCRA code yields: 1- the atmospheric transmittance in the vertical and sun directions, 2- the direct and global irradiance, 3- the single- and multiple- scattered radiance for a detector with assigned position, line of sight and field of view. Sample calculations of the main radiometric quantities calculated with MOCRA are presented and compared with the output of another RTM (MODTRAN4). A further comparison is presented between the NO2 slant column densities (SCDs) measured with DOAS at Evora (Portugal) and the ones simulated with MOCRA. Both comparisons (MOCRA-MODTRAN4 and MOCRA-observations) gave more than satisfactory results, and overall make MOCRA a versatile tool for atmospheric radiative transfer simulations and interpretation of remote sensing measurements

Perspectives of 2D and 3D mapping of atmospheric pollutants over urban areas by means of airborne DOAS spectrometers

tants, offering numerous advantages over conventional networks of in situ analysers. We propose some innovative solutions in the field of DOAS (Differential Optical Absorption Spectroscopy) remote systems, utilizing diffuse solar light as the radiation source. We examine the numerous potentialities of minor gas slant column calculations, applying the «off-axis» methodology for collecting the diffuse solar radiation. One of these particular approaches, using measurements along horizontal paths, has already been tested with the spectrometer installed on board the Geophysica aircraft during stratospheric flights up to altitudes of 20 km. The theoretical basis of these new measurement techniques using DOAS remote sensing systems are delineated to assess whether low altitude flights can provide 2D and 3D pollution tomography over metropolitan areas. The 2D or 3D trace gas total column mapping could be used to investigate: i) transport and dispersion phenomena of air pollution, ii) photochemical process rates, iii) gas plume tomography, iv) minor gas vertical profiles into the Planetary Boundary Layer and v) minor gas flux divergence over a large area

Perspectives of 2D and 3D mapping of atmospheric pollutants over urban areas by means of airborne DOAS spectrometers

tants, offering numerous advantages over conventional networks of in situ analysers. We propose some innovative solutions in the field of DOAS (Differential Optical Absorption Spectroscopy) remote systems, utilizing diffuse solar light as the radiation source. We examine the numerous potentialities of minor gas slant column calculations, applying the «off-axis» methodology for collecting the diffuse solar radiation. One of these particular approaches, using measurements along horizontal paths, has already been tested with the spectrometer installed on board the Geophysica aircraft during stratospheric flights up to altitudes of 20 km. The theoretical basis of these new measurement techniques using DOAS remote sensing systems are delineated to assess whether low altitude flights can provide 2D and 3D pollution tomography over metropolitan areas. The 2D or 3D trace gas total column mapping could be used to investigate: i) transport and dispersion phenomena of air pollution, ii) photochemical process rates, iii) gas plume tomography, iv) minor gas vertical profiles into the Planetary Boundary Layer and v) minor gas flux divergence over a large area

Individual variation in orientation promotes a 3000-km latitudinal change in wintering grounds in a long-distance migratory raptor

Migrating juvenile birds rely on endogenous information in choosing the direction in which to fly, but such input may be overridden by social interactions with experienced individuals. We tagged seven juvenile Short-toed Eagles Circaetus gallicus with GPS transmitters in southern Italy. This trans-Saharan migrant flies mainly by soaring and is therefore not well adapted to performing long water crossings. Five of the seven tagged juveniles used the longer but apparently safer route towards the Strait of Gibraltar, and two migrated along a southerly trajectory and subsequently spent the winter in Sicily, apparently forced to do so by the 150-km-wide Sicily Channel. One of these individuals took the longer route the following autumn. These results, combined with long-term (15 years) visual field observations involving thousands of individuals, suggest that inexperienced Short-toed Eagles may learn their migratory routes from experienced adults, whereas some of them migrate south in response to an innate orientation instinct. Transport costs, inherited information and geography apparently interact, forcing some Short-toed Eagles to winter 3000 km to the north of the majority of their conspecifics.The study has been funded by the Osservatorio Faunistico of Regione Basilicata through the Parco Regionale Gallipoli Cognato – Piccole Dolomiti Lucane

Analisi termica di moduli fotovoltaici per installazioni al suolo

L\u2019attivit\ue0 di ricerca riguarda lo studio degli scambi energetici di un modulo fotovoltaico con l\u2019ambiente circostante al fine di determinare la temperatura di funzionamento della cella e di individuare le azioni da intraprendere per favorire gli scambi termici ed incrementare l\u2019efficienza di conversione fotovoltaica. In particolare, lo studio ha dapprima riguardato la stima della radiazione solare al suolo in considerazione delle diverse condizione atmosferiche, e l\u2019effetto di queste ultime sulla temperatura equivalente del cielo, elemento determinante per il calcolo degli scambi radiativi del modulo fotovoltaico con l\u2019ambiente circostante. Tale attivit\ue0 \ue8 stata sviluppata in collaborazione con il Gruppo di Ricerca del Dott. G. Giovanelli e Dott.ssa M. Premuda dell\u2019Istituto di Scienze dell\u2019Atmosfera e del Clima (ISAC-CNR) di Bologna [1]-[2]. Sono state successivamente evidenziate le deviazioni dei metodi di calcolo semplificati della temperatura di cella, essenzialmente basati sul NOCT, rispetto ad un modello di scambio termico non lineare che tiene in conto dettagliatamente delle diverse tipologie di interazione con l\u2019ambiente circostante, evidenziando deviazioni significative soprattutto in condizioni di alta temperatura ambiente e/o elevati valori di irraggiamento solare [3]. L\u2019attivit\ue0 di ricerca nel settore fotovoltaico ha riguardato anche lo studio di fattibilit\ue0 ed il progetto di massima di un simulatore di radiazione solare con tecnologia LED. Il generatore multiled proposto consente una agevole modulazione della radiazione per le singole componenti spettrali, con la possibilit\ue0 di riprodurre la radiazione solare al suolo per la totalit\ue0 delle condizioni atmosferiche. Per tale attivit\ue0, tuttora in fase di sviluppo, \ue8 prevista l\u2019individuazione di un partner industriale e la realizzazione di un prototipo di simulatore di radiazione solare per celle di dimensioni fino a 15x15 cm

A transport theory approach to percolation of liquids through porous media

05.60.Cd Classical transport, 05.20.Dd Kinetic theory,