1. MM5 studies at Wageningen University (NL) Title Jordi Vilà (Group 4) NL North sea Radar MM5 NL North sea

2. MM5 research based on 4 components: Validation with detailed observations physical processes Improving physical representations Specific research studies to understand mesoscale phenomena BSc/MSc Education

3. Validation physical processes Land-surface schemes Planetary boundary layer schemes Deep Convection Microphysics Method: Intensive use of observations Sensitivity analysis

4. Energy budget R n = H + L v E + G H RnRn LvELvE G Partition of the sensible heat flux (H) and latent heat flux (E) depends on the soil moisture availability

5. Energy budget + Observations - MM5 results

6. Improving physical representations Surface and boundary layer processes Interaction land-atmosphere Entrainment

7. Are we able to improve the Nocturnal BL representation in mesoscale models? (Gert-Jan Steenveld et al., WUR) Implementation of a vegetation layer to improve representation of the surface radiative cooling Limit the turbulent mixing in stable stratifications (local scaling)

8. Temporal evolution of the surface temperature + CASES99 Observations Continuous Standard scheme Dotted Vegetation layer Dashed Veg. layer + local mixing IntermittentTurbulentRadiative Best agreement with observations after introducing vegetation lager and local turbulent mixing=> Potential impact on LLJ formation

9. + CASES99 Observations Cont. Standard scheme Dot. Vegetation layer Das. Veg.layer + local mixing Temporal evolution of the vertical profiles potential temperature Turbulent mixing decreases Radiative cooling is more effective

10. Research studies: Mesoscale phenomena strongly coupled with surface and boundary layer Method: Case studies (costal fronts, cloud formation and development,...)

11. Development of costal fronts (September-November) (Malda et al., 2007) Frictional convergenceThermal convection Backing up of the winds due to higher roughness length Convection trigger by sea/land thermal differences (accentuated at night)

12. Precipitation (dependence on land z o ) (24-hours accumulated) NL North sea NL z o (original ≈ 15 cm) z o =100 cm z o = 0.01 cm

13. Education ●MSc course (6 ECTS) Mesoscale Meteorlogical Modelling Learning emphasis on: To do research using mesoscale model Critical interpretation MM5 results ●Master thesis based on MM5 More info at: http://www.met.wau.nl/