Stationary and Nonstationary Influences of Teleconnections on Terrestrial Water Storage Anomalies in Vietnam

ABSTRACT Previous studies of teleconnection (TC) impacts on Terrestrial Water Storage Anomalies (TWSA) rarely focus on Vietnam or on the nonstationary nature of TC–TWSA relationships. This study addresses these gaps by examining both stationary and nonstationary TC influences on TWSA using correlation analysis (Pearson and cross‐spectral methods) and TC‐related TWSA extraction. The extracted TC‐related TWSA is consistent with correlation patterns: absolute zero‐lag (lagged) correlations are 0.18–0.51 (0.18–0.62), with TCs leading TWSA by 0–8 months and explaining 20%–64% of TWSA variance. Dominant TCs differ by region and are generally stronger in the south. Nonstationarity is evident from (i) large correlation shifts between 2003–2012 and 2013–2022 (e.g., from none to 0.80 or from −0.19 to 0.76) and (ii) time–frequency variability in TC–TWSA strength. Separating TCs into interannual and decadal components improves TWSA modeling, especially when distinct TCs are used for each scale; decadal influences dominate in the north, interannual in the south. These results highlight the value of timescale‐specific TC integration for TWSA reconstruction and forecasting and caution against transferring nonstationary TC–TWSA links between periods.