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| Titel |
Estimating rainfall erosivity from daily precipitation records in Campania region (Southern Italy) |
| VerfasserIn |
Giovanni Battista Chirico, Melania De Falco, Nazzareno Diodato, Nunzio Romano, Alessandro Santini |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250037807
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| Zusammenfassung |
| The assessment of rainfall erosivity, as defined by the RUSLE R-factor, depends on
availability of sub-hourly rainfall intensity time-series which are seldom available for a
significant temporal extent. Even in areas where significant sub-hourly time-series have been
recorded, their spatial distribution is too coarse to be interpolated with an acceptable level of
uncertainty.
We present a four-parameter model for estimating monthly values of the R-factor (Ri)
from mean values of the maximum daily rainfall (di) and accumulated rainfall (mi) in each
i-th month of the year. The model has been calibrated and validated by using sub-hourly
rainfall data from a set of 110 automatic raingauges which have been operating for more than
8 years in Campania Region (Southern Italy).
Ri values are estimated by power functions of di and mi, scaled by a two-parameter
periodic function. This periodic function has been specifically designed to account for the
meteorological conditions affecting the temporal variability of Ri across the year in
Mediterranean regions.
Ri is mainly controlled by the occurrence of single rainfall events of high intensity and
short duration within each month and is highly correlated with the average value of the
maximum hourly rainfall of the month (hi). Both Ri and hi exhibit marked peak values in
September, while di and mi are relatively more uniformly distributed across the rainy season,
from September to April.
Meteorological conditions in late summer and early autumn enhance the occurrence of
convective storms, characterized by high intensity and short duration, which drop almost the
entire rainfall depth observed in one month. In the rest of the rainy season rainfall
events are characterized by longer duration and lower average rainfall intensity. Thus
the functional relation between Ri and (di, mi) changes from one month to the
other. The model simulates this inter-monthly variability by the periodic scaling
function.
Tests have been performed in the calibration and validation stages, to verify the
model efficiency not only at monthly scale, but also at seasonal and annual scales. |
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