1. © Crown copyright Met Office How will we COPE in Summer 2013? - The COnvective Precipitation Experiment Phil Brown

2. © Crown copyright Met Office Table of Contents Aims Background Observations Modelling Summary

3. © Crown copyright Met Office Aims and Background

4. © Crown copyright Met Office Aims of COPE To study the production of precipitation in organized convective systems over SW England To improve the exploitation of data used for operational assimilation To improve the representation of microphysical processes in operational km-scale NWP Leading to the improvement of quantitative precipitation forecasts

5. © Crown copyright Met Office Some science questions What are the impacts of large- and meso-scale dynamics on convective precipitation? What is the representivity of line-of-sight Doppler winds from network radars and what can we learn to improve the way they are assimilated? What is the role of supercooled rain in the growth of precipitation in UK summertime convection? Which ice nucleation processes are active in these clouds, and why is -10C a magic number? What are the impacts of aerosol changes on precipitation formation and how well are these represented in the UM? Does the UM generate realistic precipitation-driven downdrafts and cold pools? Does it evaporate rain correctly? What are the relative importances of resolution, microphysics and other sub-grid processes in producing good forecasts?

6. © Crown copyright Met Office Background: Boscastle floods, 16 Aug 2004 Meteosat, high-res visible 1130Z 1530Z 1330Z1530Z Downdrafts triggering new convection Convergence line over N.Cornwall

7. © Crown copyright Met Office Background: Boscastle floods, 16 Aug 2004 Golding et al., 2005, Weather High accumulations resulted from intensity and duration of precipitation Slow-moving cells organized in along- wind lines These were not spectacular convective clouds – tops probably reaching -15 to -20C Significant involvement of both warm- rain and ice-phase processes New convection triggered by downdrafts

8. © Crown copyright Met Office Background: ICEPIC B200, 18/05/2006 Lack of precip in the upwind end of shower line – probably warm rain Excessive precip rates from cells further downwind – probably ice- phase

9. © Crown copyright Met Office Background: ICEPIC B200, 18/05/2006 UM – 4km UM – 1.5kmRadar Region of flight operations, 1100-1330Z

10. © Crown copyright Met Office Background: ICEPIC B200, 18/05/2006 Tracking single cells in a 1.5km UM simulation Liquid Ice Rain -10 -5 0 +5 -10 -5 0 +5 -10 -5 0 +5 -10 -5 0 +5 -10 -5 0 +5 -10 -5 0 +5

11. © Crown copyright Met Office Background: ICEPIC B200, 18/05/2006 Insufficient warm-rain in early stages of cloud growth Excessive precipitation rates following onset of ice-phase Ice-phase transition occurs very rapidly in 1.5km model – within 10 min similar to Phillips et al. (2001) LES study of orographically-triggered convections Aircraft observations continue to show largely unglaciated updrafts Resolution or microphysics?

12. © Crown copyright Met Office Observations

13. © Crown copyright Met Office Observations: What stuff? Plus: - MO network radars (with dual- polarization and Doppler capability) - additional radiosondes (Camborne and MRU mobile) - Doppler lidar (MRU van) - aerosol surface site (including our INCounter...) FAAM U.Wyoming King Air with WCR/WCL FGAM transportable X-band Doppler radar

14. © Crown copyright Met Office OBR priority instruments 1.The IN counter 2.The IN counter ! 3.The IN counter !!! 4.The IN counter !!!!!!!

15. © Crown copyright Met Office Modelling

16. © Crown copyright Met Office Models UKV 1.5km resolution, 36hr forecasts every 6hr 3D-VAR UKV Ensemble (2.2km) resolution High-resolution UM 100m resolution for case studies Nowcasting Demonstration Project 1.5km resolution 12hr forecasts every hour 4D-VAR

17. © Crown copyright Met Office NDP domain Focus on Olympics sites and period, 2012 Doppler weather radars in S.England 1.5km resolution Run every hour, for 12hr duration 4D-VAR with sharper error covariance matrices NDP UKV

18. © Crown copyright Met Office NDP: 29/08/2012 06Z cycle T+8

19. © Crown copyright Met Office An ideal case

20. © Crown copyright Met Office 10 May 2011

21. © Crown copyright Met Office Flight strategies Boundary-layer sampling Aerosols Cold-pool strength Gust-front – real-time winds for assimilation? Repeated penetration of single cells Updraught evolution Onset of precipitation – warm-rain First ice Ice evolution – graupel, secondary ice multiplication Penetration of multiple cells at fixed levels Life cycle of single cells

22. © Crown copyright Met Office Flight strategies Runs parallel to line at a range of altitudes / temperatures Runs perpendicular to line following a rising cloud top Sub-cloud runs sampling aerosols and boundary-layer dynamics and thermodynamics

23. © Crown copyright Met Office Field campaign questions Support for a 2-month campaign – Jul/Aug 2013 Instrument operators Operations base for 146 and King-Air Hangarage Weekend operations Operations centre at Exeter Communications to aircraft and ground sites Locations for ground sites Aerosol – incl. IN counter FGAM radar – Davidstow Moor ? MRU AWS/raingauge – Brown Willy MRU Doppler lidar - van

24. © Crown copyright Met Office FGAM radar. Possible site at Davidstow airfield MRU automatic weather station and raingauge at Brown Willy

25. © Crown copyright Met Office Questions and answers