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© Crown copyright Met Office High resolution COPE simulations Kirsty Hanley, Humphrey Lean MetOffice@Reading, UK
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© Crown copyright Met Office COPE Field campaign to study the production of precipitation in organised convective systems over SW England during July and August 2013
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© Crown copyright Met Office Aims of COPE Understand the physical processes involved in convective precipitation. Improve the representation of microphysical processes in operational km-scale NWP. Improve the exploitation of data used for operational assimilation. Leading to improved forecast of convective precipitation that can cause flash flooding.
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© Crown copyright Met Office COPE IOPs Sea breeze
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© Crown copyright Met Office UKV – 1.5km grid length, 70 levels, 2D subgrid turbulence scheme, BL mixing in vertical. 500m model – 500x400 km 200m model – 300x200 km 100m model – 150x100 km High res models: 140 vertical levels, 3D subgrid turbulence scheme, RH crit is 0.97 (0.91) in 1 st few layers decreasing smoothly to 0.9 (0.8) at ~3.5km. Set of nested models. Model setup – UM vn8.2 PS32
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© Crown copyright Met Office 18 July – popcorn convection up to 9km
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© Crown copyright Met Office 25 July – line of showers up to 3km
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© Crown copyright Met Office 29 July – organised convective line over SW peninsula
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© Crown copyright Met Office 3 August – convergence line
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© Crown copyright Met Office Summary 1 Saw quite high rainrates from warm rain. Cells appear to get smaller as grid length is reduced – this agrees with work done for DYMECS. The high resolution models maybe produce too much rain. Lines appear to break up in 200m and 100m model – why? Are the cells getting smaller a result of the updrafts getting narrower or is it a micophysics issue? Look at a sea breeze case without precipitation to isolate vertical velocity.
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© Crown copyright Met Office July 5 – sea breeze convergence
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© Crown copyright Met Office July 5 – sea breeze convergence
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© Crown copyright Met Office July 5 – sea breeze convergence FAAM obs Different colours are different times
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© Crown copyright Met Office July 5 – sea breeze convergence Vertical velocity at 325m 13Z UKV 500m 100m200m Different scale!
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© Crown copyright Met Office July 5 – sea breeze convergence Vertical velocity at 13Z UKV 500m 100m 200m 1.5 6 6 6-2 -0.5 0 0 0 0 4 1 4 4 2 0.5 2 2 0 0 0 0 1000
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© Crown copyright Met Office Westerly wind at 13Z UKV 500m 100m 200m 5 5 5-5 0 0 0 0 5 July 5 – sea breeze convergence 1000 0 0 0 0
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© Crown copyright Met Office July 5 – sea breeze convergence
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© Crown copyright Met Office Summary 2 and Future Work Updraft magnitude and width compares reasonably well between the observations and the high resolution models – how does cloud width compare? Compare simulations with lidar and King Air measurements. Identify key areas of difference between models and observations: Timing, location, size and intensity of cells.
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