Crustal response to heavy snowfalls in Hokkaido, Japan, 2018-2022

Abstract

Lands covered with snow often subside in winter by amounts detectable with modern space geodetic surveys. Such seasonal crustal subsidence would consist of numerous subsidence episodes associated with large and small snowfalls. To verify this, we study crustal subsidence of global navigation satellite system receiving stations associated with four heavy snowfall episodes 2018–2022 in Hokkaido, northern Japan. After removing common mode errors, we have detected step-like subsidence up to ∼2.5 mm of these stations. We also calculated their expected subsidences using the snow depth data from dense meteorological sensors and the load Green’s function. They are consistent with each other when we assume the average snow density of 400 kg/m³. Hence, snow loading signals are basically removable if adequate snow depth data are available. We also show that snow accretion to antenna radomes causes significant false subsidence signals, which can be distinguished by monitoring signal-to-noise ratios of the microwave signals from satellites.