Tropentag 2020, September 9 - 11, virtual conference, Germany "Food and nutrition security and its resilience to global crises"

Calibration and Validation of the LandscapeDNDC Model for Simulating Biomass Production in West African Savannah Ecosystems

¹Karlsruhe Institute of Technology (KIT), Inst. of Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU), Germany
²Université d’Abomey-Calavi (UAC), Lab. d’Hydraulique et de Maîtrise de l’Eau, Benin
³University of Copenhagen, Department of Geography and Geology, Denmark
⁴University of Montpellier, CIRAD, France
⁵University of Bonn, Inst. Crop Sci. and Res. Conserv. (INRES), Germany
⁶Deutscher Wetterdienst (DWD), Germany
⁷Géosciences Environnement Toulouse (GET), France
⁸International Livestock Research Institute (ILRI), Burkina Faso

Abstract

Savannah ecosystems, as a valuable component of the West Africa’s vegetation types, cover more than 80% of its area and provide a wide range of ecosystem services from both ecological (e.g. regulating climate) and economical (e.g. producing biomass for humans and animals) perspectives. According to the recent surveys, West African savannahs are experiencing rapid land cover and climatic changes and these changes will at the end affect their biodiversity and productivity. However, from modelling perspectives, there is still a need for parameterisation of process based biogeochemical models for modelling the behaviour of these highly dynamic ecosystems. Here, we report simultaneous calibration of LandscapeDNDC model, which is a process-based ecosystem model that simulates C, N and water cycling, using multiple observation types from flux towers and satellite images and for various typical land cover types (i.e. grasslands, shrublands, arable lands, and woodlands) in West African Sudanian and Sahelian zones. Model performance of the newly parameterised vegetation module of LandscapeDNDC was assessed on basis of several in situ above-ground biomass production measurements gathered from different sources across the Sudanian and Sahelian agro-ecological zones. Our results indicate that the LandscapeDNDC model is able to simulate biomass growth as well net ecosystem CO₂ exchange (NEE) and Leaf Area Index (LAI) realistically over periods of several years. In addition, potential applications of the LandscapeDNDC model for managed and natural ecosystems in semi-arid environments, such as impacts of climate change on seasonal biomass production and changes of regional C exchange due to land use change will be discussed.

Keywords: Calibration, landscapeDNDC model, savannah, West Africa

Contact Address: Jaber Rahimi, Karlsruhe Institute of Technology (KIT), Inst. of Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU), 82467 Garmisch-Partenkirchen, Germany, e-mail: jaber.rahimikit.edu