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).

In this note, the Water Budget Method (WBM) is applied to estimate local values of the specific yield of the deep karst aquifer of Salento peninsula. A selection in a period of two years of relevant short precipitation events has been considered and the related localized recharges have been compared to the water table fluctuations measured at two selected wells. The recharge amounts have been corrected by using data of evapotranspiration and soil water storage available from a micrometeorological base. The results are very similar for both the wells and more consistent when the corrections are applied. A discussion involving frequency and apertures of the fractures in the rock mass of the aquifer suggests the effect of the karst dissolution to be dominant in determining these values of the specific yield.

An approach based on the Penman-Monteith equation was used to estimate the actual evapotranspiration from local meteorological data over non-homogeneous land cover in a Mediterranean site in the south-east of Italy, with two six month data sets from two different years of measurements (2006 and 2009). The "critical resistance" formulation was used in different forms to model the surface resistance, together with some modifications to take into account the soil moisture content. One, two, or three model parameters were estimated, one of them related to the atmospheric resistance and the others to the surface resistance, and the calibration was made by either linear regression or nonlinear minimization of a proper cost function, depending on the applicability. Two kinds of cost functions were tested, the first depending on both the latent heat flux and the difference between screen air temperature and surface radiometric temperature, and the second depending on the temperature difference only. In all cases the calculated fluxes give better results with respect to both a flux-gradient approach and a complementarity based method, that require comparable data inputs. However the calibration by the temperature differences only, that requires no turbulent flux measurements, considerably increases the statistical uncertainty of the calibration parameters. The inclusion of the soil moisture did not significantly improve the model results in the considered site.

Two evapotranspiration models: the Penman Monteith model with a combined surface resistance (PM) and the Shuttleworth-Wallace model (SW) and have been compared for the evaluation of the partition between soil and canopy contribution to the evapotranspiration. The model parameters have been calibrated using yearly time series from the CNR ISAC-Lecce database. Both models have been arranged with 5 free (calibrated) parameters. Four of them are related to moisture response of the soil/canopy surface resistances, and the last one being respectively the Leaf Area Index (LAI) for the SW and the scalar transfer coefficient (Ch) for the PM model. After calibration, the models do not show significant overall differences in reproducing the evapotranspiration fluxes, with a slightly lower least square error for the SW model. However, the SW model shows up to a 20% increase of the soil contribution with respect to the PM model. Both models show approximately balanced soil/canopy contributions to the evapotranspiration during the wet season, while the canopy contribution tends to dominate in the dry season.

Time series of micrometeorological data from the CNR ISAC-Lecce base have been used to estimate the seasonal/yearly surface infiltration in the period 2003-2016 in the Salento peninsula (Southern Italy). The estimated values of infiltration were compared with piezometric levels measured in the regional karst aquifer during the overlapping period 2009-2011. The results, besides the complex groundwater circulation, suggest the possibility of a quite short-time component in the deep aquifer response to the recharge input. This quick response, together with the growing hydroclimatic intensity, outlined in literature studies and observed in the last decade, could increasingly affect the seasonal aquifer dynamics in the near future. Some possible consequences on the water management in karst regions under Mediterranean climate are discussed.

The Brazilian region of Pantanal is one of the largest wetlands in the world, characterized by a wet season, in which it is covered by a shallow water layer, and a dry season, in which the water layer disappears. The aim of this study is the estimation of the main parameters (drag coefficients and surface scale lengths) involved in modelling the surface atmosphere transfer of momentum, heat and water vapor from the dataset of the second Interdisciplinary Pantanal Experiment (IPE2). The roughness parameters and the stability correction parameters have been estimated in the framework of the similarity theory for the vertical profiles of wind speed and temperature. Thus, a previously-developed methodology was adapted to the available dataset from the IPE2 five-level mast. The results are in reasonable agreement with the available literature. An attempt to obtain the scalar transfer parameters for water vapor has been performed by a Penman-Monteith approach using a two-component surface resistance in parallel between a vegetation and a bare soil part. The parameters of the model have been calibrated using a non-linear regression method. The scalar drag coefficient retrieved in this way is in agreement with that calculated by the flux-gradient approach for the sensible heat flux. Eventually, an evaluation of the vegetation contribution to the total vapor flux is given.

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).

Observational estimates of the seasonal/yearly surface infiltration in the period 2003-2016 in Salento peninsula (Southern Italy) have been obtained from data time series of the CNR ISAC-Lecce micrometeorological base. The net infiltration has then been estimated and compared with piezometric levels measured in several wells of the deep karst aquifer during a governmental experimental campaign in the period 2009-2011. Within the complex characteristics of the groundwater circulation, the results suggest the possibility of a quite short-time component in the deep aquifer response to the recharge input. This quick response, together with the expected and observed growing hydroclimatic intensity, could increasingly affect the aquifer dynamics in the next future, with possible consequences on the local water management.

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

Data from 14 years (2003-2016) of activity of the ISAC-Lecce eddy covariance micrometeorological station have been analyzed with focus on the atmosphere-surface water budget in the Salento Peninsula, the far South-East region in the Italian peninsula (Apulia region). Seasonal and annual totals for precipitation and evapotranspiration have been calculated together with some suitable indices such as the aridity index, the precipitation intensity and the ground water infiltration fraction (difference between precipitation and real evapotranspiration, divided by precipitation). An analysis of the footprint associated to the measured scalar fluxes has been performed to assess their areal representativeness. An evaluation of the uncertainty of the results, related to the measurement errors, the data gaps in the time series and the surface energy budget closure has been attempted. A decadal analysis of the surface water budget is important for the evaluation of the surface water infiltration potentially affecting the recharge of the karstic aquifer that provides fresh water to the whole region.

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.

The 220km2 extended Asso Torrent basin (Apulia, Southern Italy) is crossed by natural and artificial channels flowing towards swallow holes and absorbing wells. The 7th March of 2015, the basin was struck by an unpredicted flood event. Rain intensity during the previous days was not exceptional, however damages to agriculture and dangers to vehicle traffic were experienced. In this respect, the analysis of the event may be useful to improve the alert system of the regional Protection Civil Agency.Despite of several urban and rural floods occurred in the last decades, new problems of water management raised after this event, because of the extensive hydraulic works previously made to reduce the hazard. The areas damaged by the event are placed at the lower branch of the basin (surrounding of karst swallow holes) and at the middle branch.From the analysis of precipitation of the CNR ISAC micrometeorological station it is apparent that the runoff generated by rains on 5th and 6th of March added to that of the previous days (not yet absorbed by the receptors), thus causing an overflow.The prediction of the flood events at the Asso Torrent basin needs two elements: a) a network of hydrometric stations and rain gauges; b) an efficient hydrologic model based on the actual geological features of the basin. In this note, indications are reported about these two elements in the context of a preliminary work, together with the analysis of the 2015 flooding.