The Swider Geophysical 0bservatory (SWI) used in the GloCAEM project is operated by the Institute of Geophysics, Polish Academy of Sciences. It is located 25 km South-Southeast of the Polish capital, Warsaw, and 2.5 km North-Northwest of the Otwock town, a small resort and local administrative center (population 15, 000). The bounded premises of the Observatory, some 7 ha (0.7 km3) of the surface area, are overgrown by pine and deciduous trees with a few clearings. One of these, approximately 0.7 ha, is the site of the atmospheric electricity and meteorological station. The height of the site is 96 m a.s.l.