GRACE estimates of sea surface height anomalies in the Gulf of Carpentaria, Australia

The Gulf of Carpentaria in northern Australia has a weather-driven annual periodic amplitude in sea surface height of ~ 0.4 m. Such a signal generates a mass variation that is readily detected by the GRACE mission. We used this naturally occurring phenomenon over a region of ~ 2.6 × 105 km2 to evaluate the accuracy of the GRACE estimates of temporal mass variation. Comparison of the Groupe de Recherche de Géodesie Spatiale 10-day GRACE solutions and observations from a nearby tide gauge show a correlation of 0.93, indicating that the GRGS GRACE solutions capture well the regional signal. On the other hand, the MOG2D-G barotropic model accounts for only ~ 50% of the non-gravitational annual signal, suggesting either deficiencies in the model or that some other non-barotropic process is occurring.