2 Priorities for convection parametrization Main Systematic Errors:Diurnal cycleMJOMonsoonsAEW couplingTransient responseto boundary layerFeedback with`large-scale’environment
3 Interaction with large scale Ascent generates CAPEHeating generates ascentDepth and amplitude of convective response key to improving monsoon, MJO, AEW coupling
4 Interaction with large scale progress and further work: Increased entrainment improvescoupling between convection andlarge-scale (Klingaman et al 2013)…but it can’t behigh all the time…Introduce physically realisticentrainment dependence:(stability and cloud area)Explore effects of large scale on other parts of schemeUM high resolution convection simulations over a large domain allows circulations resulting from convection to develop.
5 Interaction with boundary layer Introduce energetics of boundary layer thermalsModify triggering and closure to have dependence on thisCold poolsImportant for:1. Triggering and closureAdditional KE to overcome CINTemperature and moisture differencesallow CAPE to be present locally even when the mean state is stableEnhanced lifting2. Entrainmentaffects cloud area(and therefore buoyancyand vertical velocity)Two zones of temperature and moistureRequires memory of previous precipitation eventsMOAP secondment to work on cold pools
6 Research areas 1. Entrainment / detrainment Dependence on cloud areaDependence on stabilityAdaptivity2. Interaction with large scaleWhat is the profile of ascent caused by convective heating?How does ascent affect closure and at what levels is it important?3. Interaction with boundary layerRepresenting energetic response to CINRepresenting cold pools4. MemoryRelative importance of cloud area, rh variability, BL variabilityPrognostic for cloud area5. ClosureHow do surface processes and upper level processes combine?
7 Higher resolutions Convection position available! SeeClosing date: 14th July 2013Higher resolutionsMass flux: Separate into component partsvertical velocity, cloud area, and cloud numberMultiple plume: Quantify the need for a multi-plume approachAllows:grid-size sensitivity,inclusion of microphysicsbetter coupling with PC2stochasticityApplications submitted for Reading and Leeds CASE students to work on different aspects of grey-zone problem.
9 UnificationGive each component of the existing convection scheme an improved physical basis.Entrainment: Include dependence on stability and cloud areaDetrainment: Reformulate to be adaptive all the way up the cloud, and let the level of adaptivity depend on cloud areaTriggering and closure: Base on energetics of boundary layer processes and large-scale ascent
10 Unification details Research areas include: Cloud area representation Cold pool representationBoundary layer thermal energeticsConvective response to large-scale ascent
11 UM run Stu Webster Indian Ocean 200m from 2.2km b.c.s 4000 x 2600 points3 days
12 What controls convective depth? Vertical extent of CAPEEntrainmentDetrainmentCloud area?Boundary layer processes? (e.g. cold pools)High entrainment increases coupling to LS ascent/ descent, but it can’t be high all the time!
13 What controls heating amplitude? Rate of CAPE creation?ClosureInversion removal?Ascent?