ERA5-Land: a state-of-the-art global reanalysis dataset for land applications
Authors: Muñoz-Sabater Joaquín , Dutra Emanuel , Agustí-Panareda Anna , Albergel Clément , Arduini Gabriele , Balsamo Gianpaolo , Boussetta Souhail , Choulga Margarita , Harrigan Shaun , Hersbach Hans , Martens Brecht , Miralles Diego G. , Piles María , Rodríguez-Fernández Nemesio J. , Zsoter Ervin , Buontempo Carlo , Thépaut Jean-Noël 
Published: September 2021

Abstract. Framed within the Copernicus Climate Change Service (C3S) of the European Commission,
the European Centre for Medium-Range Weather Forecasts (ECMWF) is producing an enhanced global dataset for the land component of the fifth generation of European ReAnalysis (ERA5), hereafter referred to as ERA5-Land. Once completed, the period covered will span from 1950 to the present, with continuous updates to support land monitoring applications. ERA5-Land describes the evolution of the water and energy cycles over land in a consistent manner over the production period, which, among others, could be used to analyse trends and anomalies.
This is achieved through global high-resolution numerical integrations of the ECMWF land surface model driven by the downscaled meteorological forcing from the ERA5 climate reanalysis, including an elevation correction for the thermodynamic near-surface state. ERA5-Land shares with ERA5
most of the parameterizations that guarantees the use of the state-of-the-art land surface modelling applied to numerical weather prediction (NWP) models.
A main advantage of ERA5-Land compared to ERA5 and the older ERA-Interim is the horizontal resolution, which is enhanced globally to 9 km compared to 31 km (ERA5) or 80 km (ERA-Interim), whereas the temporal resolution
is hourly as in ERA5. Evaluation against independent in situ observations
and global model or satellite-based reference datasets shows the added value
of ERA5-Land in the description of the hydrological cycle, in particular
with enhanced soil moisture and lake description, and an overall better agreement of
river discharge estimations with available observations. However, ERA5-Land snow depth fields present a mixed performance when compared to those of ERA5, depending on geographical location and altitude.
The description of the
energy cycle shows comparable results with ERA5. Nevertheless, ERA5-Land reduces the global averaged root mean square error of the skin temperature, taking as
reference MODIS data, mainly due to the contribution of
coastal points where spatial resolution is important.
Since January 2020, the ERA5-Land period available has extended from January 1981 to the near present, with a
2- to 3-month delay with respect to real time. The segment prior to 1981 is in production, aiming for a release of the whole dataset in summer/autumn 2021.
The high spatial and temporal resolution of ERA5-Land, its extended period, and the consistency of the fields produced makes it a valuable dataset to support hydrological studies,
to initialize NWP and climate models,
and to support diverse applications dealing with water resource, land, and environmental management. The full ERA5-Land hourly (Muñoz-Sabater, 2019a) and monthly (Muñoz-Sabater, 2019b) averaged datasets presented in this paper are available through the C3S Climate Data Store at https://doi.org/10.24381/cds.e2161bac and https://doi.org/10.24381/cds.68d2bb30, respectively.