Gravity Changes Due to Continental Water Storage

Five years of global continental water storage variations are used to predict the effects of long-wavelength, long-period variability in water storage on gravity obser vations. At the sites of existing superconducting gravimeters, the modeled gravity changes have root-mean-square (RMS) values of as much as 7 Gals, with ranges of up to 22 uGals. Variations much larger than these values can be found over large regions the globe. We find that the gravity effects are predominantly annual in char acter. We also find that the modeled responses to water loading exhibit long-period variations that could be mistaken for secular tectonic trends when observed over a time span of a few years.