Fig. 4From: 2D PWV monitoring of a wide and orographically complex area with a low dense GNSS networkPWV map from the G4M procedure (a). The orographic effect is evident in elevated areas. b represents the WRF PWV map and c depicts the PWV difference map (G4M-WRF). Large differences are mainly observed in elevated areas (Alps and Apennines). The maps refer to November 4, 2011, 10:00 UTC. The contour lines correspond to PWV values of 20, 25, 30, and 35 mmBack to article page