1. © Crown copyright Met Office Cloud observations at Cardington Simon Osborne (OBR, Cardington) OBR Conference, 11 th -13 th December 2012

2. © Crown copyright Met Office Roach et al., 1976 The physics of radiation fog. QJRMS, vol 102, pp 313-333 Fog drop size distributions on slides, 1971–1972 Start of modern era… Slingo et al., 1982 A field study of nocturnal stratocumulus. QJRMS, vol 108, pp 103-123 Tethered balloon ASSP data from 1976–1978

3. © Crown copyright Met Office Instruments– present day… In situ instruments: DMT Cloud Droplet Probe (CDP) Modified for ground use Fog: 2 metre surface mount with aspirator, ~8 m s -1 Fog/St/Sc: tethered helium balloon, up to 5000ft, ambient wind Partnered with lightweight turbulence probe Ground use only e.g. fog/visibility work: Optec NGN-3a nephelometer (total scatter coeff) Grimm 1.109 aerosol spectrometer (0.2–30  m)

4. © Crown copyright Met Office Instruments— remote sensing Microwave radiometers (Radiometrics, Hatpro) Column vapour & liquid water Halo Doppler lidar, 1.5  m scanning SN 1ceiling  7 km SN 30de-polarising ( ,  ), 9 km SN 35de-polarising, 14 km for volcanic ash Vaisala LD40 ceilometer, 0.855  m (b scat only) Jenoptik CHM15k lidar, 1.064  m (b scat only)

5. © Crown copyright Met Office Halo Lidars

6. © Crown copyright Met Office Example Halo calibration red data filtered for e.g. cloud height, peak backscatter mean S = 18.53 (theory=20) Therefore scale backscatter by 1.08 S = lidar ratio (extinction to backscatter ratio) Need optically thick liquid cloud.

7. © Crown copyright Met Office Use of lidar data to measure drizzle rates below cloud… Start with calibrated backscatter, 27 th Nov 2011 “Colour ratio” = 1.5  m Halo backscatter gridded 1.5  m Halo backscatter 0.855  m LD40 backscatter gridded 0.855  m LD40 backscatter colour ratio

8. © Crown copyright Met Office Potential to look at precipitation susceptibility to aerosol concentration Mie theory to retrieve drop size, water content etc Westbrook et al (2010) Atmos. Meas. Tech., 3, 671-681 D 0 retrieval LWC retrieval Drizzle rate retrieval Drizzle rate (red=observed at 2m, black=retrieved peak) aerosol conc (black), LWP (red)

9. © Crown copyright Met Office COALESC-2012, May 29 th, Halo lidar turbulence beneath sheet of stratocumulus (TKE, m 2 s -2 per unit mass) 0.900 0.675 0.450 0.225 0.000 0.900 0.675 0.450 0.225 0.000 0.900 0.675 0.450 0.225 0.000 0.900 0.675 0.450 0.225 0.000 270 km, Chilbolton TKE 60 km, Denver Sluice TKE 0 km, Weybourne TKE 140 km, Cardington TKE

10. © Crown copyright Met Office COALESC-2011

11. © Crown copyright Met Office COALESC, March 2011 Case studies of evolution of stratocumulus over land 1–4 March Denver Sluice: ceilometer cloud base and modelled cloud depth sonde tops 1 March 1245 UTC 2 March 1245 UTC

12. © Crown copyright Met Office COALESC 16 March 2011 example of turbulence probe and CDP data from tethered balloon at Cardington

13. © Crown copyright Met Office 2 March: balloon (Cardington) and aircraft (coast) droplet size distributions equal sample volumes: balloon data = 15 min, aircraft data = 60 sec

14. © Crown copyright Met Office COALESC-2011 Profiles of droplet concentration: aircraft (off coast) balloon (Cardington) 300-600 cm -3 in moderate to high pollution, no significant drizzle

15. © Crown copyright Met Office LWP: observed and modelled (4km, 1km, 333m, 100m resolutions) 1–2 March 2011 Weybourne Denver Chilbolton Figure from Ian Boutle & Jack Eyre

16. © Crown copyright Met Office Radiation fog: overnight deployment of CDP at 2 m 24 March 2011

17. © Crown copyright Met Office Radiation fog: balloon flight on morning of 24 March 2011

18. © Crown copyright Met Office Radiation fog: droplet size distributions during profiles number volume

19. © Crown copyright Met Office Future instrument work Fog: use of CAPS (CAS bit) for looking at small fog drops: error in LWC is large <10  m Hertfordshire lightweight OPC (aerosol/cloud): balloon, UAS, ground scatter deployment Hot-wire device for measuring LWC directly ? How good are these for <10  m droplets?

20. © Crown copyright Met Office Future science work Cloud top entrainment: measure TKE and buoyancy flux profiles at top ± 100 m. Long porpoise runs with balloon video camera. Compare balloon and lidar vertical winds below cloud (and just within cloud base- viz. droplet generation region) Night-time stratocumulus: full 24 hr cycle ? Day/night turbulent structure. No night aircraft Sc flights in recent years…? Closing paragraph of Wood (2012) review paper. Doppler lidar data in general under-used regardless of meteorology / cloud conditions.