Advantage of bulk lightning models for predicting lightning frequency over Japan

Progress in Earth and Planetary Science

Table 3 Elapsed times for calculating physical components in SCALE, evaluated by simulations of five time steps from 03 UTC on 5 July, 2017 for S1

Component	WO	GS	SGS	ILU
Microphysics	3.58	3.62	3.56	3.60
Turbulence	0.85	0.81	0.84	0.85
Lightning (Mean iteration number of Bi-CGSTAB*)	155.50 (2137)	29.81 (193)	21.38 (105)	24.20 (119)
Radiation	4.14	4.12	4.10	4.08
Land/Surface	0.052	0. 052	0.053	0.053
Total	171.06	45.42	37.11	40.19

*The mean iteration number means the number of iterations per every call of subroutine for Bi-CGSTAB. For this test, the iteration was finished when the relative residual norm becomes 10^–10 or smaller
WO Without preconditioning; GS With Gauss–Seidel preconditioning; SGS With symmetric Gauss–Seidel preconditioning; ILU With incomplete lower–upper factorization preconditioning. For the calculation, the radiation processes was called once, and other physical processes were called five times