Replication data for: "Detection of atmospheric rivers affecting the Mediterranean and producing extreme rainfall over northern-central Italy"

<b> Content </b> <br>
This dataset contains atmospheric rivers (ARs) identified over the Mediterranean and impacting northern Italy. ARs have been identified as objects and the dataset contains shape, axis, date and time of each identified object. <br>
ERA5 gridded reanalyses (0.25°) provide the Integrated Vapour Transport (IVT) every 6 hours. The algorithm of Guan and Walliser (2015) has been adopted to identify ARs as objects characterized by adiacent grid points with IVT exceeding the 85th percentile, and satisfying geometrical requirements (lenght > 2000 km, aspect ratio >2). The algorithm was slighly modified to adapt to the Mediterranean (see Davolio et al., 2025 for further details).<br>
Among all the ARs identified over the full domain (-30 to 30 E; 20 to 60 N), only those affecting the target area of northern/central Italy (Italian peninsula north of about 42.5N) and at the same time extending well ouside the Mediterranean basin (defind as an arc-shaped area, see againg Davolio et al., 2025, Figure 3), have been selected. This latter requirement is devised to intercept ARs reaching the Mediterranean from either Africa tropical areas or the North Atlantic and assures a length of at least 2000 km.
Also, a temporal requirement is imposed: an AR must persist for at least three 6-hourly time steps. It means that only AR objects persisting longer than 12 hours are considered in the dataset.
<br>
The dataset covers the period 1961-2024.
<br>
Data are provided on a regular lat-lon grid, 0.25° grid-spacing, on the domain -30 to 30 E; 20 to 60 N

<br><br>
<b>Files</b> <br>
Data are in <b>netcdf format</b> and divided in decades. <br>
Naming is as yyyy_YYYY_AR.nc where
yyyy is the initial year
YYYY is the final year of the decades.
<br>
<b> Figures </b> of the IVT field and the shape identifying the AR object are also provided in png format. All the AR instants of the netcdf files have been plotted. Figures are grouped for decades (as the netcdf files) in a tgz file.
<br>
A list of the events is also provided as pdf, with initial/final time of each event, max IVT and duration.

<br><br>
<b>Software: </b><br>
- The code developed by Guan and Walliser (2015) has been adopted "Global Atmospheric River Detection" v2016.07.02 <br>
- The selection of AR satisfying our requirements was performed through python codes. <br>
- Finally, a careful manual check was necessary to remove some objects that did not resemble AR (but survived the selection for "bugs" in the code).

<br><br>
This dataset has been produced within the <b>PRIN2022 Project ARMEX</b> "Exploring Atmospheric Rivers in the Mediterranean and their connection with EXtreme hydrometeorological events over Italy: observation, modelling and impacts"
Project Next Generation EU, Mission 4, Component 1, CUP B53D23007490006 funded by Ministero dell'Università e della Ricerca<br>
https://sites.google.com/view/armexproject <br>
This research received also the support of the project “Geosciences for society: resources and their evolution” supported by the Italian Ministry of University and Research (MUR) through the funds “Dipartimenti di Eccellenza 2023/2027”.

<br><br>
<b>References:</b><br>
- Davolio, S., Sala, I., Comunian, A., Mastrangelo, D., Miglietta, M. M., Drago Pitura, L., and Grazzini, F.: Detection of atmospheric rivers affecting the Mediterranean and producing extreme rainfall over northern-central Italy, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2025-3447, 2025. <br>
- Guan, B. and Waliser, D. E.: Detection of atmospheric rivers—evaluation and application of an algorithm for global studies. J. Geophys. Res. (Atmosphere), 120, 12514–12535, https://doi.org/10.1002/2015JD0245257, 2015.