Sektion 5.5: Erdoberflächenprozess-Modellierung

Orographically-enhanced precipitation for landscape evolution modeling

The goal of this project is to evaluate the effectiveness of coupling an existing model of orographic precipitation to a landscape evolution model. Precipitation in mountainous terrain can vary dramatically over short distances, and frequently varies an order of magnitude from the windward to leeward sides of a mountain range. Moreover, we see a distinct contrast in terrain slope on opposing sides of mountain ranges today, suggesting a correlation between orography and precipitation. Most landscape evolution studies do not account for the spatial variability in precipitation. This project evaluates whether the Linear Theory (LT) of Orographic Precipitation (Smith and Barstad, 2004) effectively simulates the asymmetric pattern of precipitation as compared to modern rainfall estimates from the Tropical Rainfall Measurement Mission (TRMM). Preliminary results suggest that the LT model can do a remarkably good job of reproducing rainfall statistics *if* the number of yearly events can be adequately estimated.

Project Investigators: Dominik Schneider and Jean Braun.

Development of open-source software for interactive and exploratory modelling

Implementation of fast and extensible landscape evolution models

In geomorphology as well as in many other areas of scientific research, the growing use of computer programs, notably for running simulations, is affected by issues of reproducibility and reusability. In these areas, a lot of numerical experimentation often leads to full-featured model implementations with complex codes and interfaces that become hard to maintain. Following good software engineering practices, we try to overcome these issues by providing a common,generic framework for building computational models and running simulations. This framework encourages model creation or extension using a fine-grained modular approach, which is suited for development of scalable implementations and which leaves much room for experimentation. Highly connected to the Python scientific ecosystem,this software is also designed to increase interactivity. We use the framework to implement a set of efficient algorithms (FastScape) into versatile models of landscape evolution that will potentially include many different erosion processes (e.g., bedrock river incision, hillslope erosion, marine transport and sedimentation, glacial erosion, etc.) and their control by climate or tectonic factors. 

Project investigators: Benoît Bovy and Jean Braun

Collaborators: open to external contributions (open-source software)

xarray-simlab: https://github.com/benbovy/xarray-simlab

xarray-topo: https://gitext.gfz-potsdam.de/sec55-public/xarray-topo

 

 

Understanding the interactions between climate and fluvial erosion

There is a need to improve our understanding and modeling of how surface relief and topography affect rainfall patterns and the distribution of rainfall events both spatially and temporally, and in turn how this affects discharge distributions and patterns of erosion. In particular, it is important to develop a better understanding of the link between rainfall variability and mean, and discharge variability and mean in mountainous river catchments in order to build predictable models of long-term evolution of mountain belts, but also to predict the magnitudes and frequencies of natural hazards (e.g. landslides, floods). Currently, our understanding is limited by the assumption of uniformity of rainfall mean and variability in any catchment, which cannot be taken lightly in mountainous river catchments where the control of rainfall by orography cannot be neglected, as the mean rainfall intensity and variability varies greatly with altitude. Therefore, the main focus of this project is to answer these questions i.e. to overcome these severe limitations, and to improve the current model of the relation of rainfall to discharge characteristics by taking into account the orographic effect on precipitation, and also the effect of finite storm size in large catchments. The acquired knowledge would be used to predict how these forcings affect erosional processes characterized by a threshold (e.g. river incision, landsliding).

Project Investigators: Igor Lisac, Jean Braun, Niels Hovius.

Forschungsziele

Unsere Priorität ist die Entwicklung bzw. Verbesserung der Parametrisierung von Gleichungen zur Beschreibung von Prozessen, die die Erdoberfläche formen, sowie die Entwicklung und Bereitstellung von Methoden, um diese Gleichungen zu lösen. Dies bedeutet auch, dass wir uns der Entwicklung von Computermodellen widmen, um eine große Spannweite von Prozessen unter diversen tektonischen und klimatischen Rahmenbedingungen zu simulieren.

Das zweite Forschungsziel ist die Anwendung dieser Modelle, um zu verstehen, wie die Dynamik der Erdoberfläche auf Änderungen von Rahmenbedingungen reagiert. Solche Rahmenbedingungen umfassen tektonische Hebung und Senkung, durch Mantelkonvektion erzeugte Oberflächentopographie, Klimaveränderungen, und speziell die Auswirkungen glazialer Zyklen des Quartärs und der menschliche Einfluss während des "Anthropozäns".

Unsere aktuellen Forschungsgebiete:

  • Entwicklung eines Modells, um fluviale Erosion und Transport mit chemischer Verwitterung in angeschlossenen Hängen zu koppeln
  • Entwicklung eines quantitativen Modells der lithologischen Steuerung von Erosionsprozessen
  • Entwicklung einer effizienten und wirklichkeitsnahen Abbildung von Niederschlag- und Abflussvariabilität als Steuermechanismus für Erosionseffektivität
  • Entwicklung eines Modells für Sedimenttransport im marinen Milieu und dessen Kopplung mit einem kontinentalen Oberflächen-Prozess-Modell, um stratigraphische Ablagerungsarchitekturen vorhersagen zu können und diese in Bezug mit tektonischen und klimatischen Events zu setzen
  • Quantifizierung der Erosion im Kontinentinneren nach großskaliger Hebung und Senkung durch Mantelkonvektion (Dynamische Topographie)
  • Untersuchung des Zusammenhangs von Wasserscheidenverlagerung und geomorphologischen Prozessen und Formen.

Sie können zu unseren aktuellen Forschungsaktivitäten hier mehr erfahren.