1 / 16

High resolution COPE simulations

High resolution COPE simulations. Kirsty Hanley, Humphrey Lean MetOffice@Reading, UK. Model setup – UM vn8.2 PS32. 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

eydie
Télécharger la présentation

High resolution COPE simulations

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. High resolution COPE simulations Kirsty Hanley, Humphrey Lean MetOffice@Reading, UK

  2. Model setup – UM vn8.2 PS32 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, RHcrit is 0.97 (0.91) in 1st few layers decreasing smoothly to 0.9 (0.8) at ~3.5km. Set of nested models.

  3. 18 July – popcorn convection up to 9km

  4. 15 Aug – intense warm rain showers

  5. 25 July – line of showers up to 3km

  6. 25 July – line of showers up to 3kmScale-aware microphysics package Scheme includes new autoconversion, subgrid variability of cloud & rain, new drop-size distribution. See Boutle et al 2014, MWR for more details.

  7. 25 July – line of showers up to 3kmIan’s microphysics package New package reduces precipitation but lines still break up in 200m and 100m simulations.

  8. 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 produce too much rain. • Lines appear to break up in 200m and 100m model – why? • More cases can be seen in the report sent out last Friday. • Are the cells getting smaller a result of the updrafts getting narrower or is it a microphysics issue? • Look at a sea breeze case without precipitation to isolate vertical velocity.

  9. July 5 – sea breeze convergence

  10. July 5 – sea breeze convergence Vertical velocity at 500m amsl Different scale! Extended 200m and 100m domains by 50km to north

  11. July 5 – sea breeze convergence – FAAM obs

  12. July 5 – sea breeze convergence – FAAM obs

  13. July 5 – sea breeze convergence - Davidstow Lidar data provided by Barbara Brooks

  14. July 5 – sea breeze convergence - Davidstow

  15. 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? • What determines front propagation speed? Roll spacing/depth? • Working with Lindsay, Phil and John N on this case. • Why do high res models break up lines and produce too much precipitation? • Compare simulations with other measurements – FAAM, King Air, Radar, Lidar, surface stations. • Identify key areas of difference between models and observations: • Timing, location, size and intensity of cells. • Cases of particular interest: • 5 July, 18 July, 25 July, 3 August, 15 August

  16. July 5 – sea breeze convergence More low cloud in UKV -> lower surface temperatures -> sea breeze convergence moves slower.

More Related