Interaction of the Sea Breeze with the Urban Area of Rome: WRF Mesoscale and WRF Large-Eddy Simulations Compared to Ground-Based Observations

Abstract

The Weather Research and Forecast (WRF) model is used to simulate atmospheric circulation during the summer season in a coastal region of central Italy, including the city of Rome. The time series of surface air temperature, wind speed, and direction are compared with in situ observations in urban Rome and its rural surroundings. Moreover, the vertical wind profiles are compared to sodar urban measurements. To improve the WRF model’s ability to reproduce the local circulation, and the onset and propagation of the sea breeze, several simulations are carried out modifying the land use and the thermal and physical properties of the surfaces. Based on the results of the correlation coefficient and the RMSE, the heat capacity and albedo are the parameters mostly influencing the daily temperature cycle. Particularly, the temperature in the urban area is reproduced more realistically when the heat capacity is increased. Hence, the best simulations are used to initialize a large-eddy simulation at high spatial resolution to analyze the interaction between the sea breeze and the urban heat island and to investigate the interaction of the sea breeze front with orography and surface roughness. As confirmed by observations collected by in situ weather stations in the surroundings of Rome, the front, entering the city, splits into three branches: (i) a west component in the western flank of the city, closer to the sea; (ii) a north-west component in the northern, inland side, and (iii) a south-west component in the south area of the city.

Formaldehyde Continuous Monitoring at a Rural Station North of Rome: Appraisal of Local Sources Contribution and Meteorological Drivers

“…These latter are sea breezes coming from the direction of the Tyrrhenian Sea, which is about 50 km far from the measurement site. The advection of air masses due to the periodic sea-land circulation is of great importance for the transport of polluted air masses from Rome [45,46]. From August (see Figure S1h), the prevalent wind direction slowly returned to be northerly, and during the following autumnal months, it was accompanied by an easterly component.…”

“…The transport from Rome during the summer was due to the presence of sea breezes, which, entering inland, gradually decreased in strength [45,46] but could still be effective in transporting the urban plume downwind in the northeastern rural areas.…”

Simulating Atmospheric Characteristics and Daytime Astronomical Seeing Using Weather Research and Forecasting Model

“…In order to increase the resolution, mesoscale models of the atmosphere and methods for parametrization of turbulent characteristics are being developed in the world. The Weather Research and Forecasting (WRF) model is widely used in simulations of atmospheric movements and pollution [12][13][14][15][16][17]. In recent years, the WRF model has been used to diagnose and predict optical turbulence as well as astronomical image quality characteristics (including seeing) [18][19][20][21][22][23].…”

Assessment of the urban pollution island intensity in Rome (Italy) from in-situ PM measurements

“…5 measured in Rome (Italy) over the period 2018-2023 are analysed to evaluate the UPII. Since the correct selection of the stations used to evaluate the representative concentration in the urban area is still an open question, this study compares three different methods.…”