Hydrological loading

Hydrological loading are estimated from GLDAS/Noah (versions 1 and 2.1) [Rodell et al., 2004], ECMWF operational and reanalysis (ERA interim) models, MERRA-land [Reichle et al., 2011], MERRA2 [Reichle et al., 2017] and GRACE iterated global mascons [Luthcke et al., 2013; Bryant and Loomis, 2016; Loomis et al., 2019] (RL06v1.0). GIA effects are removed using ICE6G_D model (Peltier et al., 2018).

The spatial and temporal resolutions of the GLDAS/Noah models are respectively 0.25° and 3 hours. Permanently ice-covered areas (Greenland, Alaska and mountain glaciers) have been removed. The conservation of the total water mass has been enforced by adding/removing a uniform oceanic layer compensating any lack/excess of water over land.

The spatial and temporal resolutions of hydrological ERA interim model are about 0.7° (reduced Gaussian grid) and 6 hours. The total mass conservation has also been inforced.

The spatial resolution of the ECMWF operational varies through time, from about 0.35° in 2000 to 0.15° after 2010.

The spatial and temporal resolution of MERRA-land are respectively 0.5° and 2/3° (MERRA-land) or 0.625° (MERRA2) in latitude and longitude and 1 hour.

NASA/GSFC GRACE global iterated mascons are provided at monthly and 1° (equal area) resolutions

In each files, three different products/columns (unit: nm s^-2) are provided:

a "local" contribution (simple Bouguer approximation), which could be replaced by more precise local measurements, and more precise modelling (by taking into account the topography),
a "non-local" contribution,
the sum of the previous two, i.e. the complete loading model.

The local contribution is exactly equal to:

±4.2677 nm.s^-2 / cm (the sign depends on the location of the station with respect to the ground). We here assume that the gravimeter is always installed above the ground.

The filename gives the station name, the starting year and last year. Access to the files.