Two origins of the winter subsidence in and around the Arabian Peninsula

Hydrological surface loads, such as snowpack and soil moisture, are the main drivers of seasonal crustal movements as seen by space geodetic techniques. In addition to that, seawater sometimes exerts additional forces for coastal stations, and the atmosphere often plays an important role for stations within continents. Here we report a case in and around the Arabian Peninsula. Despite little seasonal hydrological changes there, stations show fairly uniform seasonal vertical crustal movements, characterized by ~ 1 cm winter subsidence, over the entire region. We found that they are mainly driven by the atmospheric loading. Differences in their amplitudes are compensated by large and moderate seasonal ocean mass changes in the Red Sea and the Persian Gulf (also called the Arabian Gulf), respectively, resulting in fairly uniform amplitudes of the winter subsidence in this region.