volcanic aerosol within COSP?

[Alex Hoffmann]

Dear All,

we've recently implemented an interface between COSP and our CRM ATHAM.
A colleague has also successfully ingested ATHAM data into the SDSU
simulator (http://cloud.gsfc.nasa.gov/index.php?section=14), in a form
adapted to simulate volcanic ash, and suggested an intercomparison.

This may well be a totally uniformed approach, but are there any
straightforward issues suggesting that this is impossible? I'd think
that within COSP, this could maybe only be implemented for the radar
since it is the only package that allows recomputing the scattering
coefficients?

The approach would be to:
a) implement two new large-scale microphysics categories (to avoid
SCOPS), if the vectors and matrices can easily be adapted to have
further categories
b) describe the ash distributions on the HCLASS table in cosp_constants.F90
c) add further functions that compute the refractive index of ash
particles, (assuming spherical scatterers)
d) run the simulator with modelled Mie scattering

I'd assume this to work only (if at all) away from the source (vent)
where the particle distribution is such that their diameter is small
enough for only Mie scattering to occur. I'd think non-selective
scattering to be prevalent close to the thick plume.

My questions would be:
1) is the above nonsense?
2) if not, does quickbeam within COSP have a different heritage to the
core within SDSU? Else, we'd be comparing the interfaces, not the core
simulators.
3) could this be extended for CALIPSO, i.e. could actsim be easily
adapted for aerosols, or even for other simulators?

Thanks a lot, and with my very best wishes,

Lex

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Alex HOFFMANN PhD Student
Centre for Atmospheric Science
Department of Geography University of Cambridge
Downing Place, Cambridge CB2 3EN, UK
e-mail: ah519 AT cam.ac.uk tel: +44 (0)1223 766581
www.geog.cam.ac.uk/people/hoffmann/
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