Home > Displacements > Displacements maps

Surface displacement maps
(ECMWF, TUGO-m, GLDAS)

We provided 3-hourly global displacement maps at 0.5-degree resolution due to atmospheric (ECMWF operational model), induced oceanic (Inverted Barometer or TUGO-m) and hydrological (GLDAS/Noah) loading, 6-hourly atmospheric and hydrological loading from ERA interim and 12-hourly non-tidal oceanic loading from ECCO (kf080i) model. The displacements are provided in the Center of Figure (CF) & in the Center of Mass (CM) reference frame in both ascii and netcdf format.

We use a land/sea mask model at 0.05-degree resolution for all the different loading computations, derived from the GMT (Generic Mapping Tools) database.
A model of ocean response to pressure forcing is required in order to compute atmospheric loading effects. The Inverted Barometer is classically choosen, but as it neglects the ocean dynamics, the IB model is only valid for periods exceedings typically 1-month.
We also provide an atmospheric loading model in which a dynamic ocean response to atmospheric forcing is included: we use TUGO-m (Carrere and Lyard, 2003) barotropic model forced by air pressure and winds.
Monthly tar files are provided in 7 different subdirectories:

• GLDAS: Continental hydrology loading, modeled from GLDAS/Noah.
• ATMIB: Atmospheric loading, modeled using ECMWF surface pressure, assuming an Inverted Barometer (IB) ocean response.
• ATMMO: Atmospheric (ECMWF) and induced oceanic (TUGO-m) loading.
• ERAin: Atmospheric (ERA interim) loading, assuming an IB ocean at 6-hourly time samples. Air tides (S1 & S2) have been removed by adjusting a mean monthly model.
• ERAin_hydro: Continental hydrology (ERA interim) loading at 6-hourly time samples.
• ECCO: Non-tidal ocean loading, using ECCO (kf080i) ocean general circulation model (12-hourly samples). All ECCO products have been replaced Sept. 21, 2015, and should be downloaded again.
• ECCO2: Non-tidal ocean loading using ECCO2 (0.25 degree resolution) ocean model (daily).

Figure 1: Annual vertical displacements due to atmospheric (ECMWF) and induced oceanic (TUGO-m) (left) and hydrological (GLDAS/Noah) (right) loading effects in the Center of Figure (CF) reference frame.

Careful: As TUGO-m model is forced not only by atmospheric pressure but also by surface winds, loading estimates from classical ocean general circulation model (such as ECCO) should not be added to the (ECMWF+TUGO-m) loading computations.