Impact of Typhoon Vongfong (2014) on subdaily deformation from GNSS observations

Millimeter-level transient displacements caused by extreme natural disasters are crucial for studying their dynamic processes. However, at present, such signals are rarely captured in Chinese mainland by GNSS. In October 2014, the passage of Typhoon Vongfong generated a significant storm surge, causing sea levels to rise rapidly within hours. Using 3-h displacements from GNSS stations of the Crustal Movement Observation Network of China (CMONOC) along the eastern coast of China, we evaluated non-tidal ocean loading (NTOL) effects during October 2014 by comparing the GNSS observations with model predictions. According to the NTOL predictions, vertical deformation in coastal areas in eastern China reached 2 cm, but subsidence could only be marginally detected by GNSS. Only at the Zhejiang Zhoushan station (ZJZS), the root mean square (RMS) in the vertical was reduced by 1.64 mm after removing the NTOL predictions. In the future, to capture transient signals, we will focus on integrating multi-GNSS to improve the accuracy of high-rate GNSS positioning.