How much rain is too much for a GPR survey? Results of the Borre Monitoring Project - Schneidhofer, Petra; Tonning, Christer; Cannell, Rebecca J. S.; Nau, Erich; Hinterleitner, Alois; Verhoeven, Geert J.; Gustavsen, Lars; Paasche, Knut; Neubauer, Wolfgang; Gansum, Terje (2023)