Fig. 9

GNSS stations in snowy regions often show unrealistically large subsidence. a Red, green, and blue dots in the time series indicate daily up positions of stations 0852, 0871, 0013 in Hokkaido, Japan (data from NGL/UNR). We select three such cases within pairs of vertical lines and magnify them in (b). They are artificial subsidence due to the delay of microwave signals in snow accreted to these antenna radomes, and not due to real subsidence of these stations. Such fake subsidence signals can be discriminated from real ones by plotting SNR (L2), whose decrease shows good correlations with the apparent subsidence (b)