Abstract. We describe a model to evaluate the volcanic SO2 emission using images acquired by the airborne multispectral infrared and visible imaging spectrometer (MIVIS) in the thermal infrared spectral region. The estimating procedure consists of mapping of the SO2 columnar content and evaluation of the total SO2 flux emitted by the volcano. All the atmospheric radiative effects, including the SO2 plume emission/absorption, are computed by the MODTRAN 3.5 radiative transfer code. We apply the model to two MIVIS images acquired over Mount Etna, located on the east coast of Sicily, Italy, during the "Sicilia-94" remote sensing campaign on July 24 and 25, 1994. The June 25 image was acquired during the night; this is the first attempt to estimate the SO2 content in volcanic plume using nocturnal thermal infrared images. The total flux estimates range from 20.9 kg s '• (1810 t d' •) to 82.2 kg s 4 (7100 t d' ) depending on the plume geometry used in the procedure. These results, except one case (82.2 kg s' ), are in agreement with the estimates derived from correlation spectrometer (COSPEC) measurements collected during the same period. We also evaluate the dependencies of the results on several parameters such as plume geometry, surface emissivity, water vapor content, and wind speed.

Urban mobility is known to have a relevant impact on work related car accidents especially during commuting. It is characterized by highly dynamic spatial–temporal variability. There are open questions about the size of this phenomenon; its spatial, temporal, and demographic characteristics; and driving mechanisms. A case study is here presented for the city of Rome, Italy. High-resolution population presence and demographic data, derived from mobile phone traffic, were used. Hourly profiles of a defined mobility factor (NPM) were calculated for a gridded domain during working days and cluster analyzed to obtain mean diurnal NPM mobility patterns. Age distributions of the population were calculated from demographic data to get insight in the type of population involved in mobility, and spatially linked with the mobility patterns. Census data about production units and their employees were related with the classified NPM mobility patterns. Seven different NPM mobility patterns were identified and mapped over the study area. The mobility slightly deviates from the census-based demography (0.15 on average, in a range of 0 to 1). The number of employees per 100 inhabitants was found to be the main driving mechanism of mobility. Finally, contributions of people employed in different economic macrocategories were assigned to each mobility time-pattern. Results provide a deeper knowledge of urban dynamics and their driving mechanisms in Rome.

In this paper, an algorithm is developed based on the split-window technique, to estimate the SO 2 abundance in the plume of Mt. Etna volcano using the multispectral infrared and visible imaging spectrometer (MIVIS). The MIVIS data were remotely sensed in the thermal infrared (TIR) during the Sicily-1997 Campaign. In this study, the MODTRAN 3.5 code has been used to simulate the radiance at the sensor; the radiative transfer model was input along with the data of radio-sounding performed simultaneously with the MIVIS flight using a mobile radio-theodolite. From the SO 2 map, derived from the MIVIS image, the SO 2 flux along the axis of the plume was computed knowing the wind speed at the plume altitude. The SO 2 flux is variable along the plume axis. The average SO 2 flux (about 45 kg s -1 on 12 June and about 30 kg s -1 on 16 June) emitted from the vents is compared with the correlation spectrometer (COSPEC) measurements carried out by other teams (from the ground and from a light aircraft flying under the plume) during the MIVIS flight. Finally, by means of this algorithm it should be easier, with respect to the previously described procedure to monitor the SO 2 flux of a specific volcano such as Mt. Etna.

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