Browsing by Subject "LAPSUS"

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    Modelización en Geografía Física.-Erosion in a landscape evolution context: LISEM and LAPSUS
    Baartman, J.E.M.; Schoorl, J.M.; Veldkamp, A.; Ritsema, C.J.; Universidad de Murcia
    ABSTRACT In many erosion studies only contemporary erosion is assessed, assuming this to be the direct or indirect effect of human influence. In geomorphological studies, erosion is viewed as a naturally occurring process in the context of landscape evolution. This study aims to bridge the gap between these contrasting views. In the study area (Guadalentin; SE Spain) two models are applied: the short-term, event-based model LISEM (Limburg Soil Erosion Model) and the long-term landscape evolution model LAPSUS (Landscape Process Modelling at Multi-Dimensions and Scales). LISEM needs relatively many and detailed input parameters and rainfall data. LAPSUS uses relatively simple process descriptions, input maps and average rainfall. Theoretically LISEM is expected to perform better than LAPSUS due to more detailed processes and input variables. However, spatial variability of the required characteristics is high in the study area, giving rise to high uncertainty in input and output. Therefore, LAPSUS may give better results despite the simpler process descriptions and input maps. Currently, this issue is being explored for the Guadalentin Basin on various spatial scales. Preliminary results will be presented when available. Eventually, we aim to combine the two models in a modelling framework adapted to the Guadalentin and assessing multiple scales
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    Modelización en Geografía Física.-Landscape Evolution Modelling - LAPSUS
    Baartman, J.E.M.; Temme, A.J.A.M.; Schoorl, J.M.; Claessens, L.; Viveen, W.; van Gorp, W.; Veldkamp, A.
    ABSTRACT Landscape evolution modeling can make the consequences of landscape evolution hypotheses explicit and theoretically allows for their falsification and improvement. Ideally, landscape evolution models (LEMs) combine the results of all relevant landscape forming processes into an ever-adapting digital landscape (e.g. DEM). These processes may act on different spatial and temporal scales. LAPSUS is such a LEM. Processes that have in different studies been included in LAPSUS are water erosion and deposition, landslide activity, creep, solifluction, weathering, tectonics and tillage. Process descriptions are as simple and generic as possible, ensuring wide applicability. Vegetation-effects can be included. Interactions between processes are turn-based: volumes of one process are calculated and used to update the DEM before another process starts. LAPSUS uses multiple flow techniques to model flows of water and sediment over the landscape. Though computationally costly, this gives a more natural result than steepest descent methods. In addition, the combination of different processes may create sinks during modelling. Since these sinks are not spurious, the model has been adapted to deal with them in natural ways. This is crucial for several purposes, for instance when studying damming of valleys by landslides, and subsequent infilling of the resulting lake with sediments from upstream.