Uncertainty of GRACE-borne long periodic and secular ice mass variations in Antarctica

Glacial ice mass balance of Antarctica can be observed by the twin satellites of the gravity recovery and climate experiment (GRACE). The gravity fields with monthly resolution enable efficient detection of annual, long periodic and secular variations. The present study delivers an error estimation of the long-periodic and secular variations by determining the linear trend of the observed surface mass anomaly series. Among the error sources, the error of the timing of the trend fitting, the error of the glacial isostatic adjustment correction, and the error of the atmospheric correction of the GRACE monthly solutions are discussed. The investigation concludes that apart from West Antarctica, Wilkes Land, Queen Maud Land and Enderby Land no reliable trend estimates of ice mass variation can be expected, thus any results should be treated with care.