Difference between pages "Direct effect from GLOMAP-mode aerosol to the Edwards-Slingo radiation scheme" and "ARCHER porting"
From UKCA
(Difference between pages)
Line 1: | Line 1: | ||
+ | Several of the [[UKCA Release Jobs]] have been ported from HECToR to ARCHER, and their [[UKCA_Release_Jobs#Job_List|jobids]] are detailed on that page. |
||
− | The UKCA model is configured into the HadGEM3 climate model |
||
− | with a double call to the radiation scheme to allow the |
||
− | direct radiative effect from the GLOMAP-mode aerosol to be |
||
− | calculated online in the model. |
||
+ | ==Timings== |
||
− | For the existing CLASSIC aerosol scheme used |
||
− | in HadGEM2-ES and previous HadGEM versions, |
||
− | the aerosol is considered as an external |
||
− | mixture of different aerosol types (sulphate, |
||
− | biomass, soot, biogenic and sea-salt). |
||
− | Then, for the direct aerosol forcing, the optical properties |
||
− | from each of these types was considered separately. |
||
− | The interface to the Edwards-Slingo radiation scheme used |
||
− | in HadGEM is based on look-up tables (from Mie calculations) |
||
− | for the optical properties of each particle type |
||
− | as a function of relative humidity. |
||
+ | [[File:CCMI_timings_ARCHER.png|300px|thumb|right|Scaling and efficiency profiling for N48L60 UKCa CheS+ on ARCHER]] |
||
− | In contrast to CLASSIC, GLOMAP-mode assumes each mode |
||
− | consists of an internal mixture of the different aerosol |
||
− | components (e.g. sulphate, black carbon and organic carbon). |
||
− | The water content is evaluated within this assumption using |
||
− | the ZSR algorithm (Stokes and Robinson, 1966), using water activity data from Jacobson et al. (1996). |
||
+ | The plot shows how UKCA scales when ported to ARCHER. The most efficient number of nodes to use is 3 (8x9), although the model will run fastest on 6 nodes (e.g. 16x9 or 12x12). Moving to 3 nodes from 6 will increase the run-time by 50%. |
||
− | Whereas the look-up tables for the CLASSIC aerosol scheme were |
||
− | based only on relative humidity and wavelength; for GLOMAP-mode, the |
||
− | information on mean particle radius and composition for each |
||
− | of the internally-mixed size modes is used. A volume-average |
||
− | mixing rule is used over the components present (including water) |
||
− | to calculate the real and imaginary parts of the refractive |
||
− | index. The particle size determines the Mie parameter in |
||
− | relation to the wavelength. The look-up tables have been |
||
− | calculated based on the integrals across each of the |
||
− | spectral bands for the short-wave and long-wave used by HadGEM. |
||
+ | ==Code Changes== |
||
− | For more details about the interface to the Edwards-Slingo |
||
+ | |||
− | radiation scheme and the calculations of the optical properties |
||
+ | ===Cray cce Fortran Compiler=== |
||
− | of the aerosol, please contact Nicolas Bellouin (UK Met Office) |
||
+ | |||
− | nicolas.bellouin@metoffice.gov.uk. |
||
+ | Corrections required for the Cray cce compiler on archer can be found on the [[Bugfixes#Cray_compiler_on_ARCHER|bugfixes page]]. |
Revision as of 16:12, 14 January 2014
Several of the UKCA Release Jobs have been ported from HECToR to ARCHER, and their jobids are detailed on that page.
Timings
The plot shows how UKCA scales when ported to ARCHER. The most efficient number of nodes to use is 3 (8x9), although the model will run fastest on 6 nodes (e.g. 16x9 or 12x12). Moving to 3 nodes from 6 will increase the run-time by 50%.
Code Changes
Cray cce Fortran Compiler
Corrections required for the Cray cce compiler on archer can be found on the bugfixes page.