 |
| Titel |
Temporal dynamics of hydrological threshold events |
| VerfasserIn |
G. S. McGrath, C. Hinz, M. Sivapalan  |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1027-5606
|
| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 11, no. 2 ; Nr. 11, no. 2 (2007-02-26), S.923-938 |
| Datensatznummer |
250009224
|
| Publikation (Nr.) |
 copernicus.org/hess-11-923-2007.pdf |
|
|
|
|
|
| Zusammenfassung |
| The episodic nature of hydrological flows such as surface runoff and
preferential flow is a result of the nonlinearity of their triggering and the
intermittency of rainfall. In this paper we examine the temporal dynamics of
threshold processes that are triggered by either an infiltration excess (IE)
mechanism when rainfall intensity exceeds a specified threshold value, or a
saturation excess (SE) mechanism governed by a storage threshold. We use
existing and newly derived analytical results to describe probabilistic
measures of the time between successive events in each case, and in the case
of the SE triggering, we relate the statistics of the time between events
(the inter-event time, denoted IET) to the statistics of storage and the
underlying water balance. In the case of the IE mechanism, the temporal
dynamics of flow events is found to be simply scaled statistics of rainfall
timing. In the case of the SE mechanism the time between events becomes
structured. With increasing climate aridity the mean and the variance of the
time between SE events increases but temporal clustering, as measured by the
coefficient of variation (CV) of the IET, reaches a maximum in deep stores
when the climatic aridity index equals 1. In very humid and also very arid
climates, the temporal clustering disappears, and the pattern of triggering
is similar to that seen for the IE mechanism. In addition we show that the
mean and variance of the magnitude of SE events decreases but the CV
increases with increasing aridity. The CV of IETs is found to be
approximately equal to the CV of the magnitude of SE events per storm only in
very humid climates with the CV of event magnitude tending to be much larger
than the CV of IETs in arid climates. In comparison to storage the maximum
temporal clustering was found to be associated with a maximum in the variance
of soil moisture. The CV of the time till the first saturation excess event
was found to be greatest when the initial storage was at the threshold. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|