1. Activities WG-MWFR
Help set up/involvement in RDP’s/FDP’s (COPS, Sochi, HYMEX, …)
Push mesoscale research cooperation / proposals on:
Mesoscale modelling aspects
Mesoscale DA experimentation
LAM EPS experimentation …
WMO symposia, dedicated workshops on specific topics
(Use of NWP in Nowcasting, Oct 2011; Modelling in complex terrain, spring 2012; under consideration: Physiographic data for high-resolution models)
Other activities on:
consider/promote worldwide standards for (routine) mesoscale model quality assessment
Start inventory of available mesoscale training material/activities, gaps therein
Many of these activities have important verification aspects!
JWGFVR - WG-MWFR meeting, 10 September 2011

2. Mesoscale modelling aspects
Complex terrain: steep orography, urban aspects
V2010, Sochi 2014, Tokyo Metropolitan Convection Study, Workshop HiRCoT2012
Treatment of deep/shallow convection, turbulence at various resolutions (“grey zone” aspects, role of stochasticity, etc)
Cooperation WGNE, WG-MWFR, GCSS on idealized grey zone experiments involving LES and mesoscale models
Coupling/interaction with non-atmospheric ES components: surface modelling, chemistry and aerosols, hydrology/ocean, …
Basic underlying physiographic data: good enough?
Extreme weather forecasting (e.g. typhoon)
Verification/validation: verification difficult over complex terrain (representativeness of observations); verification over urban areas; probabilistic verification; verification of extremes
JWGFVR - WG-MWFR meeting, 10 September 2011

3. Mesoscale data assimilation
How to make best use of / add value to large scale nesting analysis?
Which observations are best to use? At which density and frequency?
Surface, boundary layer, moisture and cloud information, …
How to get greatest/longest impact from moisture data?
How complex does DA technique have to be?
Hybrid ens/DA systems: how to best exploit uncertainty information for DA purposes?
How to deal with model error, imbalances, non-linearity?
New techniques needed for structure assimilation/, correction for phase errors/displacements
Cycling strategies, practical constraints/use for nowcasting applications
Etc etc …
Verification aspects: obs/model error characteristics, potential of new types of observation, cloud verification, spinup properties, verification aspects of nowcasting, …
JWGFVR - WG-MWFR meeting, 10 September 2011

4. LAM EPS research 5-10km scale LAM EPS:
Added value over global EPS clearly shown, but still suboptimal?
Do we understand the sources of uncertainty? (e.g. multi-model LAM EPS vs single-model systems with multi-physics or stochastic physics)
Hybrid ens DA: how to optimize for EPS purposes?
Potential of performance enhancement by calibration?
Push towards application on shorter time scales, more extreme events …
Towards convection-permitting EPS: scientifically huge challenge!
How to deal with uncertainty at these scales? Limits of predictability? Technology moves faster than the science!
Ease of interpretation by users:
Use of ensembles for interpretation of rare/extreme events
Training on LAM EPS use: how to interpret?
Coupling to downstream applications (hydrology, …)
Verification aspects: probabilistic verification and how to assess limits of predictability, significance, verification of extremes, …
JWGFVR - WG-MWFR meeting, 10 September 2011

5. Mesoscale verification: some general aspects
Unlike global models, no commonly accepted “gold standards” to assess and intercompare mesoscale model quality (routinely)
Experiences: There is no such thing as “the” model performance, this is strongly impacted by domain choice. Important to apply models to variety of regions (or different models to the same region), but this is rarely done.
Spatial/object-based verification methods required, in particular for precipitation (slowly entering into use) and clouds/microphysics properties (hardly done yet quantitatively).
Mesoscale models seen as particularly useful for detection of severe events. Traditional verification useless for this. Aspects of uncertainty/ probability and significance need to be addressed more.
In-depth validation/verification against supersites very useful, but this often not done due to focus on specific domains. Organize such exercises?
Common aim of our WG’s:
Define/promote recommended basic set of mesoscale quality measures
Define/promote verification methods/practices to be used in routine verification of mesoscale models, assessment of their behaviour for extreme events;
JWGFVR - WG-MWFR meeting, 10 September 2011