Methane (CH4) is an important climate forcer, contributing about 17% of the total radiative forcing by long living greenhouse gases. The Po basin is one of the most polluted and densely populated ...areas in Europe representing an important source region for CH4.
The aim of this work was to test an inter-species correlation approach to derive estimates of anthropogenic CH4 emissions for the period 2015–2019 from the Po basin by combining CO bottom-up inventory data and continuous CH4 and CO observations from a mountain site in the northern Italy. The tested methodology suggested lower emissions in respect to EDGAR (−17%) and the Italian National Inventory (−40%) for the Po basin. However, despite the two bottom-up inventories, the emissions derived from the atmospheric observations reported an increasing tendency from 2015 to 2019 for the CH4 emissions. A sensitivity study revealed that using different subsets of the atmospheric observations implied a difference of 26% in the CH4 emission estimates. The highest agreement with two bottom-up CH4 inventories (EDGAR and the Italian national inventory) were obtained when atmospheric data were strictly selected for periods representative of air mass transport from the Po basin.
Our study identified various challenges when using this methodology as a benchmark to verify bottom-up CH4 inventories. Issues could be attributed to the annual aggregation of the proxies used to derive the emission amounts, to the CO bottom-up inventory used as input information and to the relatively high sensitivity of the results to the different subsets of the atmospheric observations. However, the use of different bottom-up inventories as input data for CO emissions can potentially provide information that should be carefully considered for the purpose of integrating CH4 bottom-up inventories.
•We tested and used an inter-species correlation approach to calculate anthropogenic CH4 emissions from the Po basin.•Atmospheric observations from a mountain site were used.•Differences with bottom-up inventories were pointed out for 4 investigated years.•An accurate selection of the atmospheric data is pivotal for getting reliable information.•Yearly aggregation of data and input CO emissions led to further uncertainties.
Complex phenomena occurring in natural sciences are usually characterized by a non trivial interplay between microscopic and macroscopic dynamics, which can be successfully captured by the cellular ...automata (CA) computational paradigm 1. In this paper we show that some approximation of the classical CA paradigm is needed in order to properly deal with complex dynamical systems. Real phenomena can be efficiently modeled and simulated by introducing a modified CA approach, the CANv2 2. In this way one takes into account multiscale dynamics, through approximate infinite and/or infinitesimal dynamical stages, by means of a hybrid network of standard CA components and global operators. The power of the CANv2 approach is fully exploited by discussing three examples borrowed from the realm of natural science: debris flows after a landslide 3–5, superconductive devices 2 and forest fires spread 6,7. Advantages and limitations of our computational model explicitly arise when examples are discussed.
The sensitivity of boundary layer variables to five (two non-local and three local) planetary boundary-layer (PBL) parameterization schemes, available in the Weather Research and Forecasting (WRF) ...mesoscale meteorological model, is evaluated in an experimental site in Calabria region (southern Italy), in an area characterized by a complex orography near the sea. Results of 1km×1km grid spacing simulations are compared with the data collected during a measurement campaign in summer 2009, considering hourly model outputs.
Measurements from several instruments are taken into account for the performance evaluation: near surface variables (2m temperature and relative humidity, downward shortwave radiation, 10m wind speed and direction) from a surface station and a meteorological mast; vertical wind profiles from Lidar and Sodar; also, the aerosol backscattering from a ceilometer to estimate the PBL height.
Results covering the whole measurement campaign show a cold and moist bias near the surface, mostly during daytime, for all schemes, as well as an overestimation of the downward shortwave radiation and wind speed. Wind speed and direction are also verified at vertical levels above the surface, where the model uncertainties are, usually, smaller than at the surface. A general anticlockwise rotation of the simulated flow with height is found at all levels. The mixing height is overestimated by all schemes and a possible role of the simulated sensible heat fluxes for this mismatching is investigated. On a single-case basis, significantly better results are obtained when the atmospheric conditions near the measurement site are dominated by synoptic forcing rather than by local circulations.
From this study, it follows that the two first order non-local schemes, ACM2 and YSU, are the schemes with the best performance in representing parameters near the surface and in the boundary layer during the analyzed campaign.
•The sensitivity of boundary layer variables to five WRF PBL schemes is evaluated.•Surface measurements and acoustic/optical remote sensing instruments are adopted.•A cold and moist bias was found near the surface, mainly during daytime.•Shortwave radiation, wind speed and the PBL height are mostly overestimated.•The two non-local schemes, ACM2 and YSU, are those with best performances.
The importance of wind power forecast is commonly recognized because it represents a useful tool for grid integration and facilitates the energy trading. This work considers an example of power ...forecast for a wind farm in the Apennines in Central Italy. The orography around the site is complex and the horizontal resolution of the wind forecast has an important role. To explore this point we compared the performance of two 48 h wind power forecasts using the winds predicted by the Regional Atmospheric Modeling System (RAMS) for the year 2011. The two forecasts differ only for the horizontal resolution of the RAMS model, which is 3 km (R3) and 12 km (R12), respectively. Both forecasts use the 12 UTC analysis/forecast cycle issued by the European Centre for Medium range Weather Forecast (ECMWF) as initial and boundary conditions. As an additional comparison, the results of R3 and R12 are compared with those of the ECMWF Integrated Forecasting System (IFS), whose horizontal resolution over Central Italy is about 25 km at the time considered in this paper. v Because wind observations were not available for the site, the power curve for the whole wind farm was derived from the ECMWF wind operational analyses available at 00:00, 06:00, 12:00 and 18:00 UTC for the years 2010 and 2011. Also, for R3 and R12, the RAMS model was used to refine the horizontal resolution of the ECMWF analyses by a two-years hindcast at 3 and 12 km horizontal resolution, respectively. The R3 reduces the RMSE of the predicted wind power of the whole 2011 by 5% compared to R12, showing an impact of the meteorological model horizontal resolution in forecasting the wind power for the specific site.
Reversibility is a concept widely studied in physics as well as in computer science. Reversible computation is characterized by means of invertible properties 1. Quantum systems evolution is ...described by the time evolution operator U, which is unitary and invertible; therefore such systems can implement reversibility. Reversible/invertible Cellular Automata (CA) 1 are one of the most relevant reversible computational models. Here we introduce a model for a Josephson junction ladder (JJL) device addressing reversibility: it is based on a hybrid Cellular Automata Network (CAN), the CAN2 one234.
We present a study on the characteristics of the sea breeze flow at a coastal site located in the centre of the Mediterranean basin at the southern tip of Italy. This study is finalized to add new ...data on breeze circulations over a narrow peninsula and present a unique experimental coastal site at about 600 m from the coastline in a flat open area at the foot of a mountain chain located in a region of complex orography. We study the seasonal behaviour of the sea-land breeze circulation by analysing two years of hourly data of wind speed and direction, temperature, radiation and relative humidity from a surface meteorological station, eighteen-months data from a wind profiler, and two-year data from the ECMWF analysis. Results show that breezes dominate the local circulation and play a major role for the local climate. They are modulated by the season, through the sea-land temperature difference and the large-scale flow. The large-scale forcing acts in phase with the diurnal breeze and opposes the nocturnal breeze. In summer, the daytime difference between the land surface temperature and the SST (Sea Surface Temperature) reaches its maximum, while the nigh-time difference has its minimum. This causes a strong, frequent and intense diurnal breeze and a weak nocturnal breeze. In winter and fall the nocturnal difference between the sea and land surface temperature reaches a maximum value, while the diurnal difference is at its minimum value. This causes a strong, frequent and intense nocturnal breeze despite of the large-scale forcing that is usually opposed to local-scale flow.
The effects of the partial solar eclipse of 20 March 2015 on short-wave (SW) and long-wave (LW) irradiance measurements, meteorological variables, and near surface particle properties have been ...investigated. Measurements were performed at three southern Italy observatories of the Global Atmospheric Watch - World Meteorological Organization (GAW-WMO): Lecce (LE, 40.3°N, 18.1°E, 30ma.s.l.), Lamezia Terme (LT, 38.9°N, 16.2°E, 50ma.s.l.), and Capo Granitola (CG, 37.6°N, 12.7°E, 50ma.s.l.), to investigate the dependence of the eclipse effects on monitoring site location and meteorology. LE, LT, and CG were affected by a similar maximum obscuration of the solar disk, but meteorological parameters and aerosol optical and microphysical properties varied from site to site on the eclipse's day. The maximum obscuration of the solar disk, which was equal to 43.6, 42.8, and 45.1% at LE, LT, and CG, respectively, was responsible for the decrease of the downward SW irradiance up to 45, 44, and 45% at LE, LT, and CG, respectively. The upward SW irradiance decreased up to 45, 48, and 44% at LE, LT, and CG, respectively. Consequently, the eclipse SW direct radiative forcing (DRF) was equal to −307, −278, and −238Wm−2 at LE, LT, and CG, respectively, at the maximum obscuration of the solar disk. The downward and upward LW irradiance decrease was quite small (up to 4%) at the three sites. The time evolution of the meteorological parameters and aerosol optical and microphysical properties and their response strength to the solar eclipse impact varied from site to site, mainly because of the local meteorology and geographical location. Nevertheless, the solar eclipse was responsible at the study sites for a temperature decrease within 0.5–0.8K, a relative humidity increase within 3.5–4.5%, and a wind speed decrease within 0.5–1.0ms−1, because of its cooling effect. The solar eclipse was also responsible at all the sites for the increase of near surface particle scattering coefficient (σsp) and scattering color ratio (CRσ), mainly for the increase of both ultrafine and fine mode particle concentrations. In more detail, σsp, CRσ, and number concentration increased up to 2Mm−1, 0.2, and 9·103cm−3, respectively. The atmospheric turbulence weakening, driven by the eclipse cooling effect and revealed by the decrease of turbulent kinetic energy and potential temperature flux, mainly contributed to the changes of near surface particle concentrations and size distributions.
•The effects of the 20 March 2015 solar eclipse over southern Italy have been investigated.•SW and LW irradiance, meteorological parameters, and aerosol properties have been analyzed.•The response strength and time evolution of the tested parameters varied from site to site.•The dependence of the atmospheric response on geographical location and local meteorology has been studied.•An increase of the fine-mode particle concentration has been observed during the course of the eclipse.
In this work, new particle formation events (NPFs)
occurring at two locations in southern Italy, the urban background site of
Lecce (ECO station) and the coastal site of Lamezia Terme (LMT station), ...are
identified and analyzed. The study aims to compare the properties of NPF
events at the two sites, located 225 km away from each other and
characterized by marked differences in terms of emission sources and local
weather dynamics. Continuous measurements of particle number size
distributions, in the size range from 10 to 800 m, were performed at
both sites by a mobility particle size spectrometer (MPSS). The occurrence
of NPF events, observed throughout the study period that lasted 5 years,
produced different results in terms of frequency of occurrence: 25 % of
the days at ECO and 9 % at LMT. NPF events showed seasonal patterns:
higher frequency during spring and summer at the urban background site and the autumn–winter period at the coastal site. Some of these
events happened simultaneously at both sites, indicating the occurrence of
the nucleation process on a large spatial scale. Cluster analysis of 72 h
back trajectories showed that during the NPF events the two stations were
influenced by similar air masses, most of which originated from the
north-western direction. Local meteorological conditions characterized by
high pressure, with a prevalence of clear skies, low levels of relative
humidity (RH < 52 %), and moderate winds (3–4 m s−1)
dominated the NPF events at both sites. Notable differences were observed in
SO2 and PM2.5 concentrations and H2SO4 proxy levels,
resulting in ∼65 %, ∼80 %, and 50 %
lower levels at LMT compared to ECO, respectively. It is likely that the lower
level of that which is recognized as one of the main gas precursors involved in the
nucleation process could be responsible for the smaller NPF frequency of
occurrence (∼60 % less than ECO) observed in LMT.
Methane (CH
) is an important climate forcer, contributing about 17% of the total radiative forcing by long living greenhouse gases. The Po basin is one of the most polluted and densely populated ...areas in Europe representing an important source region for CH
. The aim of this work was to test an inter-species correlation approach to derive estimates of anthropogenic CH
emissions for the period 2015-2019 from the Po basin by combining CO bottom-up inventory data and continuous CH
and CO observations from a mountain site in the northern Italy. The tested methodology suggested lower emissions in respect to EDGAR (-17%) and the Italian National Inventory (-40%) for the Po basin. However, despite the two bottom-up inventories, the emissions derived from the atmospheric observations reported an increasing tendency from 2015 to 2019 for the CH
emissions. A sensitivity study revealed that using different subsets of the atmospheric observations implied a difference of 26% in the CH
emission estimates. The highest agreement with two bottom-up CH
inventories (EDGAR and the Italian national inventory) were obtained when atmospheric data were strictly selected for periods representative of air mass transport from the Po basin. Our study identified various challenges when using this methodology as a benchmark to verify bottom-up CH
inventories. Issues could be attributed to the annual aggregation of the proxies used to derive the emission amounts, to the CO bottom-up inventory used as input information and to the relatively high sensitivity of the results to the different subsets of the atmospheric observations. However, the use of different bottom-up inventories as input data for CO emissions can potentially provide information that should be carefully considered for the purpose of integrating CH
bottom-up inventories.
Reliable measurements of vertical profiles of wind speed and direction are needed for testing models and methodologies of use for wind energy assessment. In particular, modelling complex terrain such ...as coastal areas is challenging due to the coastal discontinuity that is not accurately resolved in mesoscale numerical model. Here, we present a unique database from a coastal site in South Italy (middle of the Mediterranean area) where vertical profiles of wind speed and direction have been collected during a two-year period from a wind-lidar ZEPHIR-300® at a coastal-suburban area. We show an overview analysis on two-year 10-minute averaged wind profiles.
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