| In the framework of the European VOLTAIRE project (Fifth Framework Programme),
simulations of relatively heavy precipitation events, which
occurred over the island of Cyprus, by means of numerical
atmospheric models were performed. One of the aims of the project
was indeed the comparison of modelled rainfall fields with
multi-sensor observations. Thus, for the 5 March 2003 event, the
24-h accumulated precipitation BOlogna Limited Area Model (BOLAM)
forecast was compared with the available observations
reconstructed from ground-based radar data and estimated by rain
gauge data.
Since radar data may be affected by errors depending on the
distance from the radar, these data could be range-adjusted by
using other sensors. In this case, the Precipitation Radar aboard
the Tropical Rainfall Measuring Mission (TRMM) satellite was used
to adjust the ground-based radar data with a two-parameter scheme.
Thus, in this work, two observational fields were employed: the
rain gauge gridded analysis and the observational analysis
obtained by merging the range-adjusted radar and rain gauge
fields.
In order to verify the modelled precipitation, both non-parametric
skill scores and the contiguous rain area (CRA) analysis were
applied. Skill score results show some differences when using the
two observational fields. CRA results are instead quite in
agreement, showing that in general a 0.27° eastward shift
optimizes the forecast with respect to the two observational
analyses. This result is also supported by a subjective inspection
of the shifted forecast field, whose gross features agree with the
analysis pattern more than the non-shifted forecast one.
However, some open questions, especially regarding the effect of
other range adjustment techniques, remain open and need to be
addressed in future works. |