1. OBR: Cloud Physics Research
Phil Brown 11/12/12

2. Table of Contents Who we are and what we do Future activities:
Coming soon to a field campaign near you
Key instruments

3. Who we are – with 1st field campaigns 
Phil Brown
First flight H335
RICO
Steve Abel
Richard Cotton
INTACC
Paul Barrett
VOCALS
Kirsty McBeath
CONSTRAIN

4. What we do Ice-phase cloud processes
deposition and aggregation growth (CONSTRAIN, PIK&MIX)
ice nucleation
Altitude
Development of parametrizations of key microphysical processes
drizzle / rain fallspeed
aerosol activation and cloud droplet number
ice crystal mass vs. size
ice crystal fallspeed vs. size
Mixed-phase cloud processes
(CONSTRAIN, PIK&MIX)
Altostratus structure and dynamics
maintenance of supercooled water layers – turbulence / ice nucleation)
Cold-air outbreak convection
cellular structures and stratiform cloud breakup
Observation comparisons with high-resolution model simulations
Unified Model
LES
KiD
Warm-cloud microphysics
Aerosols and droplet numbers (VOCALS, COALESC)
Drizzle and rain
(RICO, VOCALS, COALESC)
Temperature

5. Obtaining ice particle model parameters with in-situ aircraft observations
Often requires unique flight path.
Lagrangian descent following an evolving population of ice particles falling through the depth of cirrus.
Measure just nucleated small ice crystals near top, to large snow aggregates near base.
Extract directly from observations, model parameters that define the ice particle fall-speed as a function of size.

6. Ice bulk density as a function of particle size.
Test current UM ice density function.
Nevzorov TWC bulk water ‘truth’
Integrate PSD (with trial density) to derive predicted IWC.
Improved ice density via mass-dimension relation:
m(D)= D2.0 for D>70μm
Constant density 0.7 g cm-3 for D<70μm
© Crown copyright Met Office

7. Future field campaigns
COPE – Convective Precipitation Experiment (Jul/Aug 2013)
Prestwick (Nov/Dec 2013)
ICE-D – Ice in Clouds Experiment – Dust (Summer 2015?)
NAMSTRABBA – Namibian Stratocumulus and Biomass-Burning Aerosols (Autumn 2015?)

8. 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

9. COPE Background: Boscastle floods, 16 Aug 2004
Meteosat, high-res visible
1530Z
1130Z
Convergence line over N.Cornwall
Downdrafts triggering new convection
1330Z
1530Z

10. COPE Background: Boscastle floods, 16 Aug 2004 Golding et al
COPE Background: Boscastle floods, 16 Aug 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

11. COPE Observations: What stuff?
FGAM transportable X-band Doppler radar
FAAM
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...)
U.Wyoming King Air with WCR/WCL

12. Other campaigns Prestwick Nov/Dec 2013 ICE-D Summer 2015
Ice cloud characterisation in support of ISMAR
Ice- and mixed-phase clouds around UK
ICE-D Summer 2015
Cape Verde
Mineral dust ice nucleation and impacts on convective clouds
NAMSTRABBA Autumn 2015
Namibia
Biomass-burning aerosols and impacts on stratocumulus

13. Key instruments IN counter TWC probe
continuous-flow diffusion chamber currently under development
TWC probe
still a unique way to measure a variable that is conserved in the absence of precipitation
CVI - Counterflow Virtual Impactor
to provide alternative source of bulk ice mass
to sample ice crystal residuals
Microphysics suite
Nevzorov – bulk water
AIMMS-20
Winds / turbulence in supercooled clouds

14. Questions and answers