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| Titel |
On the role of atmospheric forcings and local soil moisture on precipitation |
| VerfasserIn |
Helio Camargo, Bart van den Hurk |
| 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 |
250040081
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| Zusammenfassung |
| The impact of land surface processes in the recent heat waves in Europe has been extensively
studied in the last couple of years, particularly after the summer 2003 episode.
Albeit the onset of a heat wave is caused by anomalous atmospheric circulation, the
amount of water in the soil (soil moisture) affects the intensity and duration of
such episodes via the control of the surface energy fluxes. In this work, we use a
conceptual model to estimate the role of the atmospheric forcings and soil moisture on
precipitation for each 4.5- x4.5- grid boxes in Europe and Africa during the JJA season.
In a control simulation (CTRL), the conceptual model was forced with realistic
moisture convergence and radiation calculated from extended time series (10,000
years) of ERA-INTERIM. The role of the forcings was assessed by calculating the
change in asymmetry and scale of the precipitation distribution between CTRL
and an idealized experiment where perfect gaussian forcings (GAU) were created
with identical mean and standard deviation as in CTRL. The role of the soil was
assessed by turning off the soil-atmosphere interaction by repeating CTRL and
prescribing daily soil moisture climatology (PRESC) derived from CTRL. In southern
Europe, soil moisture does affect the precipitation probability distribution. This
also applies for the Sahel and the central part of Africa. For the same areas, these
feedbacks increase the standard deviation of precipitation, but this effect is much
smaller than the influence of the skewed forcing. Both factors affect the likelihood of
extreme precipitation, but soil-atmosphere interaction plays a relatively minor role. |
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