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Emerging Issues in the next 20 years of relevance to WWRP and GAW

Emerging Issues in the next 20 years of relevance to WWRP and GAW. Philippe Bougeault , Météo-France. The expectations from government and society as seen from Météo-France.

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Emerging Issues in the next 20 years of relevance to WWRP and GAW

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  1. Emerging Issues in the next 20 years of relevance to WWRP and GAW Philippe Bougeault, Météo-France

  2. The expectations fromgovernment and society as seenfrom Météo-France • Improve the accuracy of short-range forecasts for security of people and properties, health, transport,defense and energymarket • Intense rainfall and flash floods • Severewindgusts • Visibility (in visible wavelengths but alsoinrared) • Risks of coastal submersion • Snowfalls and snowatground • Healththreatsfrom air quality • Developclimate services, ieimproveseasonalprediction and demonstratedecadalprediction • Frequency and severity of heatwaves and droughts • Sealevelchanges • Expertise in geo-engineering

  3. Trends for NWP systems • Integrated NWP systems (for efficiency) • nowcasting, short-range, medium-range, monthly, seasonal and decadalshouldbe part of an integrated set of codes • Seamlessforecasts (more easy to explain to users) • transition smoothlyfrom on time range to the next • Continued trend in increasedresolution • global grid <10km, regionalgrid < 500m • Generalization of ensembles • Ensembles of impact models • Towards the end of the « deterministicforecasts »?

  4. Model dynamics • Revisiting the basic equations for non-hydrostaticdynamics • More scalabledynamicalcores, optimizing the data flux between processors • More « local » discretizations, • Possiblygiving up the SI-SL and the spectral approach(???) • Towardsunstructuredgrids to betterrepresentsteeporography (like in oceanmodels)

  5. Model physics • Towards more conservative variables • Marquet’s « entropicpotentialtemperature » Θs • More advancedmicrophysics • two-moment schemeswillbecome the minimum complexity for a microphysicsscheme • Accounting for horizontal exchanges by turbulence and radiation for grids < 1km • Parametrization of convection remains a difficultproblem for grids > 5km • More « grey zone » problems as the integratedforecastssystemswillbeusedatvariousresolutions

  6. New couplingrequirements(Earth system) • Couplingwithatmospheric composition • MACC project as a forerunner • Aerosolsfirst for cloud/aerosol interactions, fogforecasts, then ozone, CO2, etc… • More requirements in mass conservation • Couplingwith continental surfaces • Emergence of tiled surface models as independant (complex) systems, coupled to the atmosphere, and in need of theirown data assimilation • Need for more realisticrepresentations of urban surfaces and boundarylayers • Couplingwith the ocean and the sea-ice • Alsoincreasingly for short-range NWP • Possiblywith an explicit description of the oceanwaves

  7. Data assimilation techniques • Evolution driven by progress in science and constraintsfrommassivelyparallel machine architectures • Increasinglyhybridmethods (ensembles-variational) • 4D-EN-VAR nowexplored in several centres • Avoids the need for TL and AD models • Requires more storage of data

  8. New observations • High spectral resolution IR sounders on geostationnary satellites (MTG in 2020) • Spacewind lidars (Aeolus in 2015) • Advanced usage of met radars • Doppler, polarimetry, refractivity • More international exchange of radar data • Towards radars/windfarms cohabitation, specific issues to explore • New types of observations • Surface wind lidars, Mode S aircraft data, opportunity data fromtelecom networks, etc….

  9. Ensembles • Work on improving description of model uncertainty • Improvelinkbetweendeterministic and stochasticphysics • Developsuitableverification techniques • Couple atmospheric ensemble with impact models • Hydrology (flood ensemble forecasts), oceanwaves, air quality (MACC regional ensemble), accidentalpollution, etc..

  10. Verification techniques • Classic NWP scores are saturatingat 24-48h forecast ranges • High resolutionrequiresprobabilisticapproach to verification • The development of ensemble requires more effort in ensemble verification techniques

  11. Upstreamresearch • Observation techniques • Drones, integratedprofilingsystems, turbulence profilingfrom doppler lidars • Field campaigns • Mediterranean (HYMEX, CHARMEX, etc…) • Atlantic (T-Nawdex) • Arcticcampaigns • Urban surface energy budget and structure of the urbanboundary layer

  12. Thankyou!

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