Twentieth Century Winter Changes in Southern Hemisphere Synoptic Weather Modes

Table 2

Periods 𝑇^𝑑𝑟 and growth rates 𝜔^𝑑𝑖 of selected modes for the 1949–68 NCEP/NCAR basic state with standard parameterizations (𝐾^𝑑=2.338×10¹⁶m⁴ s⁻¹, 𝑄^𝑑𝐹=1500K, 𝐶^𝑑𝐹=5×10⁻⁴K m⁻¹), their mode number, and class of mode. Also shown are the largest pattern correlations 𝐴_𝑐 between a given mode and the modes for the 1997–2006 NCEP/NCAR basic state with standard parameterizations and the 1997–2006 mode for which the pattern correlation is largest as well as the change in the growth rate Δ𝜔^𝑑𝑖.

Class	Mode	𝑇^𝑑𝑟	𝜔^𝑑𝑖	𝑇^𝑑𝑟	𝜔^𝑑𝑖	𝐴𝑐	Mode	Δ𝜔^𝑑𝑖
	1949–68	(days)	(day^−1)	(days)	(day^−1)		1997–2006
SH cyclogenesis	1	1.20	0.4250	1.33	0.2663	0.8960	12	−37.3%
ML blocking	30	6.11	0.2566	6.27	0.2074	0.6399	26	−19.2%
HL blocking	8	7.40	0.3495	8.01	0.3500	0.7644	5	+0.1%
HL blocking	11	5.22	0.3184	4.99	0.3060	0.8028	6	−3.9%
NWCB	43	8.01	0.2100	7.97	0.3054	0.6374	7	+45.4%
Antarctic	6	13.08	0.3624	20.0	0.3810	0.9071	3	+4.9%
Antarctic	26	52.1	0.2746	∞	0.2850	0.6475	10	+3.8%
ISO	57	59.0	0.1444	25.4	0.1886	0.5744	33	+30.6%
African EW	22	4.14	0.2881	3.86	0.3035	0.7638	8	+5.3%