The development of reliable strategies for an adapted land management that can cope with climate change in West Africa requires a detailed analysis of the feedback mechanisms between the components of the land surface and the atmosphere. However, the process descriptions of land surface – atmosphere interactions are poorly represented in atmospheric models and state-of-the-art models cannot be used for a suitable feedback analysis. The current land surface schemes in atmospheric models used for the description of the exchange of water and energy between soil, vegetation and atmosphere have at least two shortcomings:
- The information used to describe the land surface is usually time-invariant. But certain features of the land surface such as e.g. the vegetation cover are characterized by a high intra- and inter-annual variability.
- A further weakness is the poor representation of subsurface fluxes. To tackle these problems, the process descriptions of atmospheric models must be refined and have to be specifically adapted to the land surface and atmospheric processes of West Africa. To realize this goal, a high resolution regional climate modeling system for the West African region will be designed in this WP.
This modeling system consists of three main components:
- Data assimilation schemes based on statistical techniques for integrating atmospheric and dynamic land surface information into the modeling system;
- A two-way coupled atmospheric-hydrological modeling system using process-based algorithm to describe the majority of processes of the West African climate system;
- Statistical techniques for local refinement and bias correction of the outcomes of the atmospheric-hydrological modeling system.
The primary focus of this Work Package is the establishment of the dynamical component of the regional modeling system and the specific adaptation of the process descriptions of this model to the processes of the West African climate system. The land surface scheme of a state-of-the art regional climate model will be parameterized by dynamic land surface properties derived from enhanced remote sensing technique. It will be also coupled with a distributed process-based hydrological model that allows for a two-way coupling required for feedback analysis. This modeling system will be used to provide high resolution climate information for a recent period. This information is of utmost importance to describe long-term changes of climate variables in the Sudanian Savanna.
A further major task of this Work Package is the installation of climate stations and eddy covariance stations in the focal watersheds. The climate information provided by the stations is crucial for the analysis of the West African climate system, in particular to improve the process understanding of the feedback mechanisms between the atmosphere and the land surface. The climate information plays also a key role for the evaluation of the regional climate modeling system. Furthermore, the regional climate modeling system and the stations will deliver crucial information needed for the field experiments proposed in the Core Research Programme.
Finally, the climate information provided by the modeling system and stations can be used to determine key indicators describing the state of the ecological subsystem in that region and that are needed to assess the resilience of the SES for the watersheds selected in WASCAL. Thus, the development of a regional climate modeling system specifically adapted to the processes of the West African climate system and the installation of climate and eddy covariance stations plays a key role in WASCAL. In the end of the project, a workshop and training course will be given to transfer the outcomes of the proposed research activities to practice and to offer the novel techniques to the members of the Competence Centre and further partners involved in WASCAL.