## 2 Material and Methods  
This study is based on integrated data sets and methods including analysis of meteorological data acquired by weather stations, wave measures by sea buoy, wind and wave analyses, and interpretation of detailed digital elevation model (DEM) and orthophoto derived by UAS (Unmanned Aircraft System) surveys. The first step in the analysis of the 28 December 2020 sea storm event has been the reconstruction of the meteorological scenario both at a large scale (Europe and central Mediterranean area) and at a local scale. The large-scale meteorological study has been carried out based on forecasting and reanalysis maps derived by meteorological models and EUMETSAT satellite images (see link at: [[https://www.eumetsat.int](https://www.eumetsat.int)]([https://www.eumetsat.int](https://www.eumetsat.int)), accessed on 6 September 2021). These data are available from open access International Meteorological Service (2021) and have been used to reconstruct the main features and evolution of the atmospheric systems that caused the storm event discussed in this study, with particular attention to the evolution of wind intensity through time. Local meteorological  
Figure 1: Location of the study area. Large scale—Italy (**a**), regional scale—Campania (**b**), local scales—Gulf of Naples (**c**), and Naples seafront (**d**) maps. Names of major localities cited in the text are also reported. data, along with tidal and wave data used for this research, have been collected from various institutions:  
- \"Consiglio Nazionale delle Ricerche-Istituto di Scienze Marine\" (CNR-ISMAR)-meteorological data by a Campi Flegrei network [23];  
- \"Istituto Superiore per la Protezione e la Ricerca Ambientale\" (ISPRA)-\"Rete Mareografica Nazionale\" [24]; meteorological and tidal data in the Port of Naples;  
- \"Istituto Nazionale di Geofisica e Vulcanologia-Osservatorio Vesuviano\" (INGV-OV)-\"MEDUSA Project\"-tidal data by instrumented buoys operating in the Gulf of Pozzuoli [25]; and  
- University of Naples \"Parthenope\"-waves data by instrumented buoy operating in the Gulf of Naples (courtesy of prof. [PERSON], Parthenope University). The CNR-ISMAR meteorological monitoring network (Table 1) is composed of four weather stations, equipped with Davis Instruments-Vantage Pro2 model [26], located along the coastal area of the Naples district (Figure 2). The network has been implemented to investigate the influence of meteorological factors on geomorphological coastal processes, such as cliff retreat, landslides, beach erosion, and sea storms. The four weather stations (WS) are described in Tables 2 and 3. The Integrated Sensor suite detects temperature, relative humidity, barometric pressure, rain, and wind (speed and direction). The sensors of ISPRA meteorological and tidal station WS-05-Port of Naples (40\({}^{\circ}\)50'29.06\" N-14\({}^{\circ}\)16'09.10\" E) are described on the institutional ISPRA website and include an ultrasonic anemometer [27]. The characteristics of the tide gauge sensor of the INGV-OV buoy in the Gulf of Pozzuoli (40\({}^{\circ}\)48'32.47\" N, 14\({}^{\circ}\)8'39.33\" E) are documented on the institutional INGV-OV website (Medusa Project) [25]. Sea waves data are recorded by an active buoy managed by the University of Naples \"Parthenope\", located in the southern part of the Gulf of Naples (Figure 2) off the coast of Massalubrense (40\({}^{\circ}\)37.127\" N, 14\({}^{\circ}\)19.415\" E; bathymetry: \(-\)50 m). The buoy has a floating body in polyethylene and includes a central metal structure on which the different modules are installed. The system is equipped with a datalogger for data acquisition; it records the measurements on the internal memory and transmits data in real time to a remote computer through a UTMS (Universal Mobile Telecommunications System) modem. The sensor mounted on the turret of the buoy body is based on a GNSS (Global Navigation Satellite System) receiver for the detection of height and direction of the waves.