Optimisation of the simulation particle number in a Lagrangian ice microphysical model
This paper presents various techniques to speed up the Lagrangian ice microphysics code EULAG-LCM. The amount of CPU time (and also memory and storage data) depends heavily on the number of simulation ice particles (SIPs) used to represent the bulk of real ice crystals. It was found that the various...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-04-01
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| Series: | Geoscientific Model Development |
| Online Access: | http://www.geosci-model-dev.net/7/695/2014/gmd-7-695-2014.pdf |
| Summary: | This paper presents various techniques to speed up the Lagrangian ice
microphysics code EULAG-LCM. The amount of CPU time (and also memory and
storage data) depends heavily on the number of simulation ice particles
(SIPs) used to represent the bulk of real ice crystals. It was found that the
various microphysical processes require different numbers of SIPs to reach
statistical convergence (in a sense that a further increase of the SIP number
does not systematically change the physical outcome of a cirrus simulation).
Whereas deposition/sublimation and sedimentation require only a moderate
number of SIPs, the (nonlinear) ice nucleation process is only well
represented, when a large number of SIPs is generated. We introduced a new
stochastic nucleation implementation which mimics the stochastic nature of
nucleation and greatly reduces numerical sensitivities. Furthermore several
strategies (SIP merging and splitting) are presented which flexibly adjust
and reduce the number of SIPs.
These efficiency measures reduce the computational costs of present cirrus
studies and allow extending the temporal and spatial scales of upcoming
studies. |
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| ISSN: | 1991-959X 1991-9603 |