estimate name   : ECCO version 4 release 2 ocean state estimate
estimate source : Gael Forget, on behalf of the ECCO consortium
support contact : ecco-support@mit.edu
references      : Forget, G., J.-M. Campin, P. Heimbach, C. N. Hill, R. M. Ponte,
                  and C. Wunsch, 2015: ECCO version 4: an integrated framework for
                  non-linear inverse modeling and global ocean state estimation.
                  Geoscientific Model Development, 8, 3071-3104, doi:10.5194/gmd-8-3071-2015

released files history :
   2016/03/24 : second release of ECCO v4 (GF)
   2014/02/04 : initial release of ECCO v4 (GF)

state estimate revision history (see Forget et al 2015):
   rev4it12   : include geothermal heating, targeted bottom
     viscosity, and 2000-2011 wind stress adjustments that
     were omitted in r4it11; adjust global mean precipitation
     to closely match aviso global mean time series; put
     adjusted forcing fields on llc90 grid (GF).
   rev4it11   : reduce background vertical viscosity (GF).
   rev4it10   : cleanup control vector adjustments (GF).
   rev4it9    : optim. global mean sea level alone (GF).
   rev4it0-8  : full adjoint iterations, omitting global 
     mean sea level altimetry constraint (GF).
   rev1,rev2,rev3 : preliminary adjoint iterations (GF).