Poltoradnev, M. and Ingwersen, J. and Streck, T.
(2017)
Spatial and temporal variability of soil water content in two regions of Southwest German.
In: Jahrestagung der DBG 2017: Horizonte des Bodens, 02.-07.09.2017, Göttingen.
Abstract
Soil water content (SWC) plays a key role in partitioning of energy and water fluxes on the land surface. Knowledge about spatial and temporal variability of topsoil water content is crucial for understanding land surface processes, improving climate and hydrology modeling. In recent study, we investigated SWC variability, its relation to the mean spatial soil water content (qm) and variability of rainfall on the regional spatial and event temporal scales. To accomplish this, we used a multi-year high resolution data set, obtained from two soil moisture sensor networks (spatial extent of 25 km ×25 km), set up at croplands in Kraichgau and Swabian Alb regions in Southwest Germany. The relationship of SWC standard deviation (sq) versus áqñ was studied (sq-qm). It was found that the initial location of sq in relation to the sq at the permanent wilting point (sq-qwp) and the sq at saturation (sq-qs) – the anchor points – as well as the upper and lower bounds of the sq-qm envelope determine whether SWC variability increases or decreases upon a change in qm. sq-qm relationship forms combinations of concave and convex hyperbolas reflecting the variability of soil texture and depending on sq in relation to the anchor points. The majority of sq-qm clockwise hysteresis cases were observed in intermediate and intermediate/wet state of SWC. The sq phase-space can be used to test whether hydrological or land surface models capture the reasonable range of soil water heterogeneity.
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