{"references": ["Dee, D. P., Uppala, S. M., Simmons, A., Berrisford, P., Poli, P., Kobayashi, S., Andrae, U., A. Balmaseda, M., Balsamo, G., Bauer, P., Bechtold, P., C. M. Beljaars, A., van de Berg, L., Bidlot, J., Bormann, N., Delsol, C., Dragani, R., Fuentes, M., J. Geer, A., Haimberger, L., B. Healy, S., Hersbach, H., V. Holm\u00b4 , E., Isaksen, L., Kallberg, P., Kohler , M., Matricardi, M., McNally, A. P., Monge-Sanz, B. M., Morcrette, J-J., Park, B-K., Peubey, C., de Rosnay, P., Tavolato, C., Thepaut, J-N., & Vitart, F. (2011). The ERA-interim reanalysis: Configuration and performance of the data assimilation system. Quarterly Journal of the royal meteorological society, 137 (656), 553\u2013597.", "Van der Ent, R., Tuinenburg, O., K\u00f1che, H.-R., Kunstmann, H., & Savenije, H. (2013). \u00a0 Should we use a simple or complex model for moisture recycling and atmospheric moisture tracking? Hydrology and Earth System Sciences, 17 (12), 4869\u20134884.", "Van der Ent, R., Wang-Erlandsson, L., Keys, P. W., & Savenije, H. (2014). Contrasting roles of interception and transpiration in the hydrological cycle\u2013part 2: Moisture recycling. Earth System Dynamics, 5 (2), 471\u2013489."]}

The WAM-2layers is an Eulerian moisture tracking numerical model. We used the Python version available on the GitHub repository (https://github.com/ruudvdent/WAM2layersPython). For a detailed description of the WAM-2layers, we refer the reader to van der Ent et al. (2013, 2014). Moisture tracking was conducted forward in time, focusing on the fate of evapotranspiration contributing to Terrestrial Moisture Recycling to calculate the amount of precipitation with continental origin. Our tracking experiment spans from 1979 to 2018. The model domain covers a global grid from 79.5ºN to 79.5ºS latitude. Calculations use data of specific humidity, zonal and meridional wind speeds at 24 pressure levels, surface pressure at 6-h intervals, and 3-h accumulated precipitation and evaporation, from the ERA-Interim reanalysis (Dee et al., 2011) on a 1.5º grid with 25,680 cells total (nx=240, ny=107). This set-up is based on previous studies indicating that it is adequate to track moisture spatially, both forward and backward in time and at regional and global scales.

The P_track_continental_full1979-2018.mat file was built using the python version of The WAM-2layers model available on the GitHub repository (https://github.com/ruudvdent/WAM2layersPython). To continue, variables in the file are described: E_per_year_per_month: Total evaporation in m3/month, P_track_per_year_per_month: Recycled precipitation in m3/month, P_per_year_per_month: Total precipitation in m3/month. Our tracking experiment spans from 1979 to 2018. Calculations were performed on a 1.5º grid with 25,680 cells total (nx=240, ny=107). Thus, the file has the next dimensions [year=40,month=12,lat=107,lon=240]. Examples of posproccessing scripts can be found in https://github.com/ruudvdent/WAM2layersPython. For a detailed description of the WAM-2layers and variables, we refer the reader to van der Ent et al. (2013, 2014).