A New Land Surface Hydrology within the Noah-WRF Land-Atmosphere Mesoscale Model Applied to Semiarid Environment: Evaluation over the Dantiandou Kori (Niger)

B. Decharme (1, 2) , Catherine Ottle (2) , S. Saux-Picart (3) , N. Boulain (4) , B. Cappelaere (4) , David Ramier (4, 5) , Mehrez Zribi (6)

1 CNRM - Centre national de recherches météorologiques
2 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
3 CETP - Centre d'étude des environnements terrestre et planétaires
4 HSM - Hydrosciences Montpellier
5 IRD/Niamey
6 CESBIO - Centre d'études spatiales de la biosphère

Land-atmosphere feedbacks, which are particularly important over the Sahel during the West African Monsoon (WAM), partly depend on a large range of processes linked to the land surface hydrology and the vegetation heterogeneities. This study focuses on the evaluation of a new land surface hydrology within the Noah-WRF land-atmosphere-coupled mesoscale model over the Sahel. This new hydrology explicitly takes account for the Dunne runoff using topographic information, the Horton runoff using a Green-Ampt approximation, and land surface heterogeneities. The previous and new versions of Noah-WRF are compared against a unique observation dataset located over the Dantiandou Kori (Niger). This dataset includes dense rain gauge network, surfaces temperatures estimated from MSG/SEVIRI data, surface soil moisture mapping based on ASAR/ENVISAT C-band radar data and in situ observations of surface atmospheric and land surface energy budget variables. Generally, the WAM is reasonably reproduced by Noah-WRF even if some limitations appear throughout the comparison between simulations and observations. An appreciable improvement of the model results is also found when the new hydrology is used. This fact seems to emphasize the relative importance of the representation of the land surface hydrological processes on the WAM simulated by Noah-WRF over the Sahel.

Domaines: Hydrologie; Milieux et Changements globaux

B. Decharme, Catherine Ottle, S. Saux-Picart, N. Boulain, B. Cappelaere, et al.. A New Land Surface Hydrology within the Noah-WRF Land-Atmosphere Mesoscale Model Applied to Semiarid Environment: Evaluation over the Dantiandou Kori (Niger). Advances in Meteorology, 2009, 2009, ID 731874 (13 p.). ⟨10.1155/2009/731874⟩. ⟨hal-00485075⟩