Atmospheric Dispersion by yurtgc548

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									                   MM5 studies at
Title          Wageningen University (NL)

                                                  North sea
North sea



                   NL                                          NL



              Radar                                           MM5



                               Jordi Vilà (Group 4)
  WA G E N I N G E N U N I VE R S I T Y
  M E TE O R O L O G Y A N D A I R Q U A L I TY
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
Validation physical processes

Land-surface schemes
Planetary boundary layer schemes
Deep Convection
Microphysics


Method:
Intensive use of observations
Sensitivity analysis
                 Energy budget

Partition of the sensible heat flux (H) and latent heat
flux (E) depends on the soil moisture availability



                            Rn = H + LvE + G


                       Rn


                              H      LvE
                                           G
                 Energy budget

+ Observations
- MM5 results
      Improving physical representations

      Surface and boundary layer processes
                                 Entrainment




Interaction
land-atmosphere
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)
         Temporal evolution of the
           surface temperature

                                       + CASES99 Observations
                                       Continuous Standard scheme
                                       Dotted     Vegetation layer
                                       Dashed     Veg. layer + local
                                                   mixing



                                       Best agreement with
                                       observations after
                                       introducing vegetation
                                       lager and local turbulent
Intermittent   Turbulent   Radiative   mixing=>
                                       Potential impact on LLJ
                                       formation
       Temporal evolution of the
vertical profiles potential temperature



                        + CASES99 Observations
                        Cont. Standard scheme
                        Dot. Vegetation layer
                        Das. Veg.layer + local
                              mixing

                         Turbulent mixing
                         decreases

                         Radiative cooling
                         is more effective
Research studies:

Mesoscale phenomena strongly coupled with
surface and boundary layer




Method:
Case studies (costal fronts, cloud formation
and development, ...)
            Development of costal fronts
            (September-November) (Malda et al., 2007)


   Frictional convergence        Thermal convection




Backing up                   Convection trigger by
of the winds due to          sea/land thermal differences
higher roughness length      (accentuated at night)
     Precipitation (dependence on land zo)
                    (24-hours accumulated)

zo (original ≈ 15 cm)       zo=100 cm            zo= 0.01 cm
 North sea              North sea            North sea




               NL                   NL                    NL
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/

								
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