The micrometeorological base of CNR-ISAC in Lecce, South-East of Italy, is active since 2002, in collecting experimental data about surface-atmosphere transfer of momentum heat and water vapour. It operates in a suburban site inside the Salento University campus and has been improved along the past years in terms of active sensors to give a quite complete description of the soil-atmosphere vertical transfer. It is composed by a 16 m mast with fast response (eddy correlation) instrumentation and an ancillary automatic meteorological station collecting also soil data at 2 levels depth. Fast response data are pre-processed in half-hour averaged statistics. All collected data are available in a web database (www.basesperimentale.le.isac.cnr.it) where they can be either visualized or downloaded. At present the Lecce data base is also a pilot reference structure for the Climate Change Section of the CNR-DTA GIIDA project (National Research Council - Earth and Environment Department, Interdisciplinary and Interoperative Management of Environmental Data), aimed to build a spatial data infrastructure between different CNR-DTA structures collecting environmental data. It is also a data provider for the Hymex project database ( Hydrological Mediterranean Experiment, www.hymex.org).

This work reports an analysis of the concentration, size distribution, and depositionvelocity of atmospheric particles over snow and iced surfaces on the Nansen Ice Sheet(Antarctica). Measurements were performed using the eddy-correlation method at a remotesite during the XXII Italian expedition of the National Research Program in Antarctica(PNRA) in 2006. The measurement system was based on a condensation particle counter(CPC) able to measure particles down to 9 nm in diameter with a 50% efficiency and aDifferential Mobility Particle Sizer for evaluating particle size distributions from 11 to521 nm diameter in 39 channels. A method based on postprocessing with digital filterswas developed to take into account the effect of the slow time response of the CPC. Theaverage number concentration was 1338 cm-3 (median, 978 cm-3; interquartile range,435-1854 cm-3). Higher concentrations were observed at low wind velocities. Resultsgave an average deposition velocity of 0.47 mm/s (median, 0.19 mm/s; interquartile range,-0.21 -0.88 mm/s). Deposition increased with the friction velocity and was on average0.86 mm/s during katabatic wind characterized by velocities higher than 4 m/s. Observedsize distributions generally presented two distinct modes, the first at approximately15-20 nm and the second (representing on average 70% of the total particles) at 60-70 nm.Under strong-wind conditions, the second mode dominated the average size distribution.

Harbours are important hubs for social and economic development of coastal Mediterranean areas. However, ship emissions are also a significant source of atmospheric pollution in port-cities with potential effects on both human health and climate. At European level (Viana et al., 2014), the impact of shipping to particulate matter (PM) concentrations is larger in Mediterranean area with respect to Northern Europe. Further, information on impact on ultrafine and nanoparticles is still fragmentary and not sufficient to have a global picture on this metric. International legislations to reduce ship emissions, both at Worldwide and European levels, are mainly based on the use of low-sulphur content fuel that is effective also in reducing primary impact of shipping to atmospheric aerosol (Contini et al., 2015).In the framework of POSEIDON project, a measurement campaign was performed between 27th June and 15th October 2014, in the harbour area of Brindisi (SE Italy, 40° 38? 43.32? N - 17° 57? 36.39? E). A mobile laboratory was used to investigate the contribution of ship traffic and harbour activities (hotelling, loading and unloading of ships) to gaseous pollutants and to concentrations of atmospheric particles of different sizes.The mobile laboratory was equipped to measure, at high temporal resolution, gaseous pollutants (NO2, NO, O3, SO2 at 5 minutes resolution), total particle number concentrations (Grimm CPC 5.403 at 1 minute resolution), particle size distribution in the range 0.25-34 µm using a Grimm OPC 1.109 (1 minute resolution) and further, a DOAS (Differential Optical Absorption Spectroscopy) remote-sensing system was employed for detection of NO2 and SO2 fluxes from ships in harbour (Premuda et al., 2011). Ship traffic details were collected from Brindisi Port Authority and arrival and departure times were synchronised with concentration measurements using a night & day video camera. A low-volume PM2.5 sequential sampler was used to collect 24-hour samples using the gravimetric method to calibrate optical measurements.Collected data allowed to individuate short-term concentration peaks associated with ship traffic and concentration increases associated with correlated harbour activities. An example is reported in Figure 1. Measurements show that SO2 presents brief concentration peaks associated with the manoeuvring phase and lower concentrations during the hotelling phase. This is compatible with the use of low-sulphur content fuel in European harbours (European Directive 2012/33/EC). Nitrogen oxides concentrations show a significant contribution, especially for NO, for both manoeuvring and hotelling, loading/unloading phases. Simultaneously, a depletion of O3 (not shown) was observed. Particle concentrations show a dynamics that is strongly depending on particle size. Ultrafine particles (diameter Dp<0.25 µm) show peaks well correlated with nitrogen oxides peaks. Instead, accumulation mode particles (0.25 µm<Dp<1 µm) show concen

The aim of this study is gaining further understanding of the structure of the marine atmospheric boundary layer (MABL) and its interaction with the synoptic scale forcing. A possible application of this study is to simulate mean and turbulent spatial and temporal structure of the marine boundary layer in order to optimise the structural design of offshore large wind turbines that now-a-days reach height up to 200 m. Large-Eddy Simulation (LES) have been performed and compared with offshore experimental data collected during the LASIE campaign performed in the Mediterranean in Summer 2007. Two simulations are performed: in the LES-NOFR run, the LES is left free to evolve without any external forcing, while in the LES-FR run a force-restore nudging technique has been implemented in LES, in order to force the model to the large-scale evolving situation. Model results have been compared against experimental soundings. Results show that the LES-FR outperforms the simulation without force-restore nudging for all the fields, demonstrating that incorporating changes in the large-scale features into the model is necessary in order to provide a realistic evolution of the meteorological fields at local scale.Thus, LES appears as a promising technique to be applied to the simulation of offshore cases, particularly suitable for wind energy applications.

The studies involving flow in offshore wind conditions increased in recent years. This interest is directly associated with the design conditions for wind turbines and wind farm aiming at optimizing the production of wind energy and the risk analysis during the lifetime a wind farm. In this context, the aim of this study is gaining additional understanding of the structure of the marine atmospheric boundary layer (MABL) and its interaction with the synoptic scale forcing. A potential application of this study is to simulate mean and turbulent spatial and temporal structure of the marine boundary layer in order to optimise the structural design of offshore modern wind turbines that may reach height up to 200 m. Large-Eddy Simulation (LES) have been performed and compared with offshore experimental data collected during the LASIE campaign performed in the Ligurian Sea during Summer 2007. Two simulations are performed under different synoptic conditions. Model results have been compared against experimental soundings. Results show that LES outperforms the mesoscale simulation, indicating that the inclusion of large-scale features into the model is necessary to provide a realistic evolution of the meteorological fields at local scale. In this context, LES appears as a promising technique, particularly suitable for offshore wind energy applications

The micrometeorological base of CNR-ISAC in Lecce, South-East of Italy, is active since 2002, in collecting experimental data about surface-atmosphere transfer of momentum heat and water vapour. It operates in a suburban site inside the Salento University campus and has been improved along the past years to give a quite complete description of the soil-atmosphere vertical transfer. It is composed by a 16 m mast with fast response (eddy correlation) instrumentation and an ancillary automatic meteorological station collecting also soil data at 2 levels depth. Fast response data are pre-processed in half-hour averaged statistics. All collected data are available in a web database (www.basesperimentale.le.isac.cnr.it) and represent a unique long-term daily updated dataset for microclimate and soil use changes studies in southern Italy. Here some preliminary results about the evolution of the surface water budget in the last years are presented. The Lecce data base has been a pilot reference structure for the Climate Change Section of the CNR-DTA GIIDA project (National Research Council - Earth and Environment Department, Interdisciplinary and Interoperative Management of Environmental Data). It is also a data provider for the HYMEX project database (Hydrological Mediterranean Experiment, www.hymex.org).

In the marine environment, complete datasets describing the surface layer and the vertical structure of the Marine Atmospheric Boundary Layer (MABL), through its entire depth, are less frequent than over land, due to the high cost of measuring campaigns. During the seven days of the Ligurian Air-Sea Interaction Experiment (LASIE), organized by the NATO Undersea Research Centre (NURC) in the Mediterranean Sea, extensive in situ and remote sensing measurements were collected from instruments placed on a spar buoy and a ship. Standard surface meteorological measurements were collected by meteorological sensors mounted on the buoy ODAS Italia1 located in the centre of the Gulf of Genoa. The evolution of the height (z(i)) of the MABL was monitored using radiosondes and a ceilometer on board of the N/O Urania.Here, we present the database and an uncommon case study of the evolution of the vertical structure of the MABL, observed by two independent measuring systems: the ceilometer and radiosondes. Following the changes of surface flow conditions, in a sequence of onshore - offshore - onshore wind direction shifting episodes, during the mid part of the campaign, the overall structure of the MABL changed. Warm and dry air from land advected over a colder sea, induced a stably stratified Internal Boundary Layer (IBL) and a consequent change in the structure of the vertical profiles of potential temperature and relative humidity.

Osservatorio Climatico-Ambientale di I-AMICA a Lecce: attività e prospettive di un centro d'eccellenza al servizio del territorio

A one-year (July 2013-July 2014) dataset of PM2.5 and PM10 was collected at the Environmental-Climate Observatory (regional station of the Global Atmosphere watch - GAW-WMO), recently built in an urban background area in Lecce (SE Italy, 40°20'8''N-18°07'28''E, 37 m asl) within the I-AMICA project (PON R&C 2007-2013). Roughly, one sample every three days was chemically analysed for a total of 226 simultaneous samples (113 for each size fraction). Elemental and organic carbon were determined via thermo-optical method (Sunset OC/EC analyser, NIOSH5040 protocol), major ions Cl-, NO3-, SO42-, C2O42-, Ca2+, Na+, K+, Mg2+ via IC and 23 metals via ICP-MS (Li, Al, Ti, V, Mn, Fe, Co, Cu, Zn, As, Se, Rb, Sr, Nb, Cd, Sb, Ba, La, Ce, Nd, Dy, Pb, Th). The dataset was analysed using mass closure stoichiometric calculations for sea-spray, secondary inorganic aerosol (SIA) and crustal matter and using Positive Matrix factorization model (PMF5) to investigate the seasonal trends of eight particle sources (sea-spray, nitrate, sulphate, biomass burning, crustal, crustal carbonates, traffic, and industrial). Several cases of sea-spray events were observed with an average contribution of 16% to the coarse fraction (PM10-2.5) and 3% to PM2.5. Larger contributions were observed in autumn and winter and in high winds periods. Sea-spray interacted with nitric acid with a consequent chloride depletion, 60% on average for both PM2.5 and PM10. The Cl- depletion was significantly larger at high temperature during spring and summer with a trend opposite to that of secondary nitrate that was lower during spring and summer due to its thermal instability. Secondary nitrate had larger concentration in the coarse fraction at high temperature, instead at lower temperature the fine fraction of nitrate dominated. Organic matter was evaluated as OM=1.6xOC and represented 31% (PM10) and 43% (PM2.5), EC represented 2.7% (PM10) and 3.1% (PM2.5). Carbonaceous species were higher during autumn and winter with OC well correlated with K+ supporting the relevant contribution of biomass burning found with PMF5. Secondary organic carbon, evaluated with the minimum OC/EC ratio, was entirely segregated in PM2.5 accounting for 80% of total OC. Two crustal contributions were found, one characterised by metal oxides representing long-range transport of dust including Saharan dust advection, and the other characterised by crustal carbonates (mainly calcium carbonates) compatible with the local soil composition (limestone). Secondary sulphate was mainly ammonium sulphate/bisulphate entirely segregated in PM2.5, however, during intense cases of Saharan dust advection, a coarse component of CaSO4 was observed.

Data from a ten years (2003-2013) period of activity of the ISAC-Lecce micrometeorological station have been discussed focusing on the atmosphere-surface exchange. Some suitable indices have been calculated such as the precipitation intensity, the aridity index and the ground water infiltration fraction (ratio of the difference between precipitation and real evapotranspiration and the precipitation). Possible trends of annual averages in the decadal period are considered, trying to take also into account the statistical uncertainty associated to measurement errors and missing data. The results indicate a significant increasing in the precipitation intensity together with an experimental evidence of increasing of the ground water infiltration in the measurement area that is in agreement with recent estimations for the whole Salento peninsula. Nevertheless, during the same period the marine water intrusion together with salinization of the deep aquifer keep increasing, thus requiring attention in the hydrological modelling of the Salento deep aquifer and/or in its management for freshwater supply.

Data of surface-atmosphere energy and water transfer from a ten years (2003-2013) period of activity of the ISAC-Lecce micrometeorological station (http://www.basesperimentale.le.isac.cnr.it) have been analyzed: to the authors' knowledge this is the first decadal data set of surface-atmosphere transfer in Salento peninsula. The surface energy budget shows a tendency to a positive bias possibly due to several reasons that require more investigations. Some suitable indices related to the surface water balance, such as the precipitation intensity, the aridity index and the ground water infiltration fraction have been calculated. Possible trends of these annual averages in the decadal period are considered, also taking into account the statistical uncertainty associated to measurement errors and missing data. The results indicate a significant increasing in the precipitation intensity together with an experimental evidence of increasing of the ground water infiltration in the measurement area, that is in agreement with recent estimations for the whole Salento peninsula. On the other hand, recent studies show that seawater intrusion and salinization of the deep underground aquifer keep increasing in the same period.