Woolnough Alision Stirling WP21ab High Resolution Simulations of Convection GOAL To inform parametrization development and in particular improve the temporal evolution of convection convective memory ID: 615812
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Natalie Harvey, Steve
Woolnough, Alision Stirling
WP2.1a,b High Resolution Simulations of Convection
GOAL: To inform parametrization development and in particular improve the temporal evolution of convection (“convective memory”)Slide2
Idealised cloud-resolving simulations
2
“Radiative” Equilibrium ConvectionImposed “radiation”Interactive “radiation”500km x 500km at ~100m resolution
500km x 500km
at ~
100m
resolution
Diurnal cycle over land
Homogeneous surface
Heterogenous
surface
500km x 500km
at ~
100m
resolution
500km x 500km
at ~
100m
resolution
Also companion simulations at 4km, 12km and ~40km resolutionSlide3
Natalie Harvey, Steve
Woolnough, Alision Stirling
WP2.1a,b High Resolution Simulations of Convection
TODAY: Development of tools to analyse the TKE budget of an idealised diurnal cycle Slide4
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Analysis methods and tools
Reynolds averaged budgets: TKE, w’
2
, w’
θ
’
Whole domain, steady state flow
Sub-domains – extra terms
Which terms control departures from local steady state?
Conditionally-sampled diagnostics
Spectral diagnostics
e.g. look at buoyant cloudy updrafts only
Scales for dissipation and production
Upscale and down scale transportsSlide5
TKE budget equation
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TKE: Horizontal homogeneity and neglect subsidence
I: Tendency
III: Buoyancy
IV: Shear
V: turbulent transport
VI: pressure correlation
VII: DissipationSlide6
Diurnal cycle
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Using LEM 2D Horizontal grid: 512 x 1kmVertical grid: 76 levels with 20 km top Surface forcing based on EUROCS, balanced by large scale cooling 20 days with 10 minute output Time (hours)Wm-2Slide7
How different?
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Time (hours)
Height (km)Slide8
How different?
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Time (hours)Height (km)Height (km)Vertically integrated qxVertically integrated qx
Cycle 3
Cycle 12Slide9
How different?
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Time (hours)precipitationVertically integrated TKESlide10
TKE budget terms
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Time (hours)
Time (hours)Slide11
TKE budget terms
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Composite of 18 diurnal cycles Slide12
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TKE budget terms:
vertical integralsSlide13
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TKE budget terms:
vertical integrals
Time (hours)
Vertically integrated TKE
Vertically integrated budget term
Wm
-2Slide14
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TKE budget terms:
regression on to vertically integrated TKE Slide15
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Conditionally sampled diagnostics
How does TKE relate to conditionally averaged diagnostics? Time of vertically integrated TKE maximumSlide16
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Spectral diagnostics
Spatial spectra2D vertical velocity - instantaneous every 10 minsTransports? Slide17
Next steps?
Continue the development of tools to analyse the diurnal cycle
Reynolds averaged budgetsExtend to: Conditional samplingSpectral diagnostics
Design and perform the high resolution simulations (MONC or idealised UM?)
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