Page 1 Met Office © Crown copyright 2007 CAMM model performance assessed during DODO2 Steph Woodward – climate model dust scheme Glenn Greed – implementation of dust in the CAMM model – Running of operational forecasts for use in DODO2 flight planning Mark Harrison– NAME model forecasts Jim Haywood– Analysis of aircraft data Sundar Christopher– Satellite retrievals/validation

Page 2 Met Office © Crown copyright 2007 Description of the CAMM:  Non-hydrostatic  Two-time level semi-implicit semi- Lagrangian scheme  Charney-Philips staggering in the vertical  Arakawa C grid in the horizontal  Data assimilation (4-D var) satellite, sonde, surface, and data from commercial aircraft

Page 3 Met Office © Crown copyright 2007 Description of the CAMM:  Domain:-  Resolution: 0.18°x0.18° resolution (~20km)  38 levels in the vertical  13 levels in the boundary layer.

Page 4 Met Office © Crown copyright 2007 Description of the dust scheme:  Dust scheme based on Woodward (2001)  6 size bins in the range μm radius  Dust emission is based on the scheme by Marticorena and Bergametti (1995)  Dust flux a function of: clay, silt, and sand fraction, vegetative fraction, soil moisture, friction velocity threshold, and surface layer friction velocity.  Convection, turbulent mixing, gravitational settling accounted for  Dry and wet deposition

Page 5 Met Office © Crown copyright 2007 Description of the dust optical properties:  Mie scattering  Spherical particles  6-wavebands in the solar spectrum  9- wavebands in the long-wave  AOD diagnostic developed at 0.55μm

Page 6 Met Office © Crown copyright 2007 Modifications when moving from climate model:  Soil data set in climate model - Wilson and Henderson-Sellers (1985) at 3.75 o replaced by International Geosphere Biosphere Programme (IGBP, Loveland and Belward, 1998) at 1kmx1km.

Page 7 Met Office © Crown copyright 2007 Additional modifications:  The threshold friction velocities were reduced by 0.15ms -1 and is now defined for all particle sizes spanning 0.06 to 2000μm diameter (rather than 0.06 to 60μm as in W2001).  Horizontal dust flux calculations now include sand particles. The vertical flux is still assumed to consist only of particles between.06 and 60μm.  A correction to the dust uplift code have also been introduced which inhibits emissions of dust from steep slopes.

Page 8 Met Office © Crown copyright 2007 CASE STUDY – AUG 23rd

Page 9 Met Office © Crown copyright 2007 The dust forecast from the 21 st August

Page 10 Met Office © Crown copyright 2007 The dust forecast from the 21 st August

Page 11 Met Office © Crown copyright 2007 The dust forecast from the 21 st August

Page 12 Met Office © Crown copyright 2007 The dust forecast from the 21 st August Tropical storm Debbie Dust storm within range of BAe146

Page 13 Met Office © Crown copyright 2007 A t+9 forecast: Tropical storm Debbie Dust storm within range of BAe146

Page 14 Met Office © Crown copyright 2007 The problems of model validation are shown by the MISR coverage:

Page 15 Met Office © Crown copyright 2007 Therefore correlative methods of MISR-OMI are developed (Christopher et al):

Page 16 Met Office © Crown copyright 2007

Page 17 Met Office © Crown copyright 2007 Comparison of dust event with Dakar AERONET

Page 18 Met Office © Crown copyright 2007 Flight pattern on the 23 rd August 2006

Page 19 Met Office © Crown copyright 2007 Comparison of the vertical profile from aircraft against the CAMM vertical profiles for two aircraft deep profiles.

Page 20 Met Office © Crown copyright 2007 MONTHLY MEAN COMPARISONS

Page 21 Met Office © Crown copyright 2007 Can also look at the monthly means:

Page 22 Met Office © Crown copyright 2007 Monthly mean comparisons:

Page 23 Met Office © Crown copyright 2007 AERONET monthly means:

Page 24 Met Office © Crown copyright 2007 Conclusions: Case study:  The CAMM model shows SKILL up to (and beyond?) 42hours.  The horizontal position and vertical extent of the dust is well represented  The optical depth is reasonably well represented Monthly means:  The OMI/MISR comparisons show a reasonable agreement  AERONET shows a reasonable agreement