The re-analyses of past land-atmosphere conditions constitute a major numerical modelling and data assimilation undertaking, involving the use of supercomputers and supported by dedicated research programs. Therefore the pace at which a global multi-decadal reanalysis can be re-run, and benefit from model and data assimilation advances, is normally of the order of 5 to 10 years. A computationally affordable method to reactualize only the land surface component of a given reanalysis is proposed and its merits and limitations are presented in the framework of the latest ECMWF reanalysis covering the period 1979-2011 (ERA-Interim). In the land-surface only runs the ERA-Interim reanalysis is used in conjunction with other datasets (e.g. GPCP precipitation) to force a new version of the ECMWF land surface model. Recently available ground-based networks with high frequency observations covering several years are used to verify this approach in particular for the variables of soil moisture, snow depth and turbulent latent and sensible fluxes at the surface.