Advantages of a Gridded
Precipitation Analysis to Verify ECMWF Precipitation Forecasts over Europe
High-density
rain-gauge reports have been used to build a gridded precipitation analysis over
Europe. Both deterministic and perturbed forecasts (Ensemble Prediction System)
are assessed against this analysis. Comparisons between verification using
local observations and verification against the analysis will also be shown.
The time evolution of the bias score shows a
slight but consistent improvement, with a progressive reduction of
over-forecasting of rainy events. The European rainy season (October to March)
is investigated in some detail. Results show that the Equitable Threat Score
has an annual cycle with the rainy months (October to March) scoring better
than the summer ones.
The
results achieved so far underline the need for high-density data for any
verification procedure that wants to ascertain the performance of a forecasting
system. In this way spatial scales of the model are compared to similar spatial
scales in the precipitation analysis. The representativeness problem associated
with individual station location becomes negligible.