A revised hydrology for the ECMWF model: Verification from field site to terrestrial water storage and impact in the Integrated Forecast System

The Tiled ECMWF Scheme for Surface Exchanges over Land (TESSEL) is used
operationally in the Integrated Forecast System (IFS) for describing the evolution of
soil, vegetation and snow over the continents at diverse spatial resolutions. A revised
land surface hydrology (HTESSEL) is introduced in the ECMWF operational model,
to address shortcomings of the land surface which appeared in the absence of surface
runo and in the choice of a global uniform soil texture. New inltration and
runo schemes are introduced with their dependency on soil texture and standard
deviation of orography datasets. A set of experiments in stand-alone mode allows
assessing the improved prediction of soil moisture at local scale against field site
observations. Comparison with Basin-Scale Water Budget (BSWB) and Global
Runo Data Centre (GRDC) datasets indicate a consistently larger dynamical range
of land water mass over large continental areas, and an improved prediction of river
runoff while being largely invariant with respect to atmospheric
uxes. Finally the
ECMWF data assimilation and prediction systems are used to verify the impact on
surface and near-surface quantities in atmospheric-coupled mode. A mid-latitude
error reduction is registered both in soil moisture and in 2m temperature.