Spatio-temporal evolution and teleconnection factor analysis of groundwater drought based on the GRACE mascon model in the Yellow River Basin

Gravity Recovery and Climate Experiment (GRACE) gravity satellite can provide data for large-scale drought assessment, making up for the disadvantage that the traditional groundwater drought monitoring methods cannot accurately obtain groundwater drought information. In this study, the GRACE mass concentration (mascon) model was adopted for exploring the multi-timescale groundwater drought variations. Taking the Yellow River Basin (YRB) as the study area, the spatiotemporal evolution law and trend of groundwater drought during 2003–2020 were comprehensively investigated by the model; the relations between groundwater drought and teleconnection factors were disclosed by the cross wavelet transform technology, in which the analysis highlighted four key findings: (1) the data obtained by GRACE were verified to be credible, contributing to the evaluation of groundwater drought; (2) the standardized groundwater drought index (SGDI) was –0.65 in 2006, indicating the serious groundwater drought appeared in that year; (3) the groundwater droughts in both monthly and seasonal scales were increasing during 2003–2020; and (4) the influence of teleconnection factors, especially the El Nino-Southern Oscillation (ENSO), cannot be ignored in formation of groundwater drought in the YRB. The evaluation of groundwater drought variations was realized by GRACE mascon model, providing a technical reference for similar studies in other watersheds.