TITLE:
A Study of Precipitation Climatology and Its Variability over Europe Using an Advanced Regional Model (WRF)
AUTHORS:
Hari Prasad Dasari, Venkata Srinivas Challa
KEYWORDS:
Regional Climate, Rainfall, Europe, WRF-ARW, Threat Score
JOURNAL NAME:
American Journal of Climate Change,
Vol.4 No.1,
March
6,
2015
ABSTRACT: In recent
years long-term precipitation trends on a regional scale have been given
emphasis due to the impacts of global warming on regional hydrology. In this
study, regional precipitation trends are simulated over the Europe continent
for a 60-year period in 1950-2010 using an advanced regional model, WRF, to
study extreme precipitation events over Europe. The model runs continuously for
each year during the period at a horizontal resolution of 25 km with initial/ boundary
conditions derived from the National Center for Environmental Prediction (NCEP)
2.5 degree reanalysis data sets. The E-OBS 0.25 degree rainfall observation
analysis is used for model validation. Results indicate that the model could
reproduce the spatial annual rainfall pattern over Europe with low amounts (250
- 750 mm) in Iberian Peninsula, moderate to large amounts (750 - 1500 mm) in
central, eastern and northeastern parts of Europe and extremely heavy falls
(1500 - 2000 mm) in hilly areas of Alps with a slight overestimation in Alps
and underestimation in other parts of Europe. The regional model integrations
showed increasing errors (mean absolute errors) and decreasing correlations
with increasing time scale (daily to seasonal). Rainfall is simulated
relatively better in Iberian Peninsula, northwest and central parts of Europe.
A large spatial variability with the highest number of wet days over eastern,
central Europe and Alps (~200 days/year) and less number of wet days over
Iberian Peninsula (≤150 days/year) is also found in agreement with
observations. The model could simulate the spatial rainfall climate variability
reasonably well with low rainfall days (1 - 10 mm/days) in almost all zones,
heavy rainfall events in western, northern, southeastern hilly and coastal
zones and extremely heavy rainfall events in northern coastal zones. An
increasing trend of heavy rainfall in central, southern and southeastern parts,
a decreasing trend in Iberian Peninsula and a steady trend in other zones are
found. Overall, the simulated rainfall climatology was reproduced well for the
low and heavy rainfall followed by very heavy and extremely heavy rainfall in
Europe and the simulation is better in the Iberian west coast, central northern
Europe and Alps Mountains.