What Cause the Common-Mode Error in Array GPS Displacement Fields: Case Study for Taiwan in Relation to Atmospheric Mass Loading

Abstract

We analyze 47 best-quality, 10-year-long daily Global Positioning System (GPS) position time series of Taiwan, to understand the origin of the GPS's common-mode error (CME) whose seasonality in the standard deviation evidences a meteorological origin. We employ the empirical orthogonal function analysis to efficiently extract the CME as the leading island-wide mode for all three components (whereas the second mode relates to the El Niño Southern Oscillation). We find that the CME correlates well with the acquired variations in the atmospheric mass loading (AML) displacement field for Taiwan courtesy of NASA Goddard Space Flight Center for the vertical component with high coherence around 11-14 cycles per year. Further regression analysis shows that the maximum 90% of the non-seasonal AML displacements in Taiwan are evident in the CME variations. Plain Language SummaryThe extracted common-mode error-long period, high amplitude, in-phase daily fluctuations-from the continuous GPS data is compared with the atmospheric mass loading displacements in Taiwan. The time and frequency domain correlation study reveals a significant correlation between the two in between 26 and 33 days/cycle with lag around or less than 1 day. Up to 90% of the common-mode error variations can be explained by the quantitative variations in atmospheric mass loading.