DATE2022-06-21 21:31:31
TITLETowards an improved representation of the surface-atmosphere coupling over Moroccan semi arid plains with the LMDZ-ORCHIDEE climate model
AUTHORSKhadija Arjdal (1,2) ,Fatima Driouech (1) ,Étienne Vignon (3) ,Frédérique Chéruy (3) ,Adriana Sima (3) ,Philippe Drobinski (2) ,Abdelghani Chehbouni (1) ,Salah Er-raki (1,4)
  1. 1) Mohammed Vi Polytechnic University, International Water Research Institute (iwri)/center For Remote Sensing Applications (crsa), Benguerir (Morocco) ,2) Lmd/ipsl, École Polytechnique, Institut Polytechnique De Paris, Ens, Psl Research University, Sorbonne Université, Cnrs, Palaiseau (France) ,3) Laboratoire De Météorologie Dynamique (lmd), Ipsl, Sorbone Université, Cnrs, Umr 8539, Paris (France) ,4) Procede, Département De Physique Appliquée, Faculté Des Sciences Et Techniques, Université Cadi Ayyad, Marrakech (Morocco)
ABSTRACTThe Haouz plain in Morocco suffers from several changes in land use, coupled with water scarcity and exacerbated by climate change. Assessing the parameterisation of the surface couplings over semi-arid plains in climate models is critical to improve the reliability of future scenarios. The objective of this work is to assess and improve the representation of the physical processes driving the surface-atmosphere couplings over the Haouz plain in the IPSL-CM climate model. We set-up a simulation with the atmosphere-surface LMDZ-ORCHIDÉE component, with a grid refined over the Haouz plain. The model is nudged towards atmospheric reanalysis outside of the region of interest to guarantee consistent large scale meteorological fields. Model outputs are evaluated with local observations collected at 3 meteorological stations in the plain. Results show overall good performances of the model on reproducing rainfall events with a reasonable representation of the climate over the region. However, in-depth analyses hold an underestimated soil moisture, near-surface humidity and latent heat flux that can be primarily attributed to the absence of a parameterization of irrigation in the model. Hence, our current work is based on setting the new irrigation module of the ORCHIDÉE surface model with a routing version consistent with our zoomed configuration. Moreover, since the monitoring stations with orange (Agafay) and olive (Agdal) crops are not totally representative of the mesh-size region, a sensitivity test of land cover effect on near surface climate was performed. Results showed a significant decrease of wind speed biases attributed to the increase of roughness height, however, there was no significant impact on near surface temperature and humidity nor the energy and the radiative balances. We also investigate the surface dynamical and thermal couplings in order to explain the wind and temperature biases.