The Variability of Arctic Sea Ice Extent from Spring to Summer and Its Linkage to the Decline of SIE in September

Table 1

Statistical analyses of the five sea ice extent (SIE) differences (unit: millions of square kilometers (Mkm²)) for April minus May (AM), May minus June (MJ), June minus July (JJ), July minus August (JA), and August minus September (AS) during 1979–2012 and the correlation between September SIE and these five SIE differences. Trends significant at 95% and 99% confidence level are indicated with asterisks as (5) and (1); correlation coefficients higher than 0.339 and 0.435 are defined as at 95% (5) and 99% (1) confidence levels, respectively.

Statistics valueSIE difference	Apr-May	May-Jun	Jun-Jul	Jul-Aug	Aug-Sept
Mean (Mkm^2)	1.37	1.53	2.24	2.48	0.72
Standard variance (Mkm^2)	0.19	0.34	0.41	0.29	0.27
Liner trend rate (per year)	−0.0047	0.0139	0.0263	0.0062	0.0135
Maximum (Mkm^2)/year	1.76/1983	2.28/2010	3.37/2007	3.22/2012	1.32/2008
Minimum (Mkm^2)/year	0.98/2007	0.66/1989	1.45/1983	1.75/2001	0.19/1980
The corr. of SIE in Sept	0.163	−0.499	−0.786	−0.477	−0.691
The corr. after detrending	−0.092	−0.323	−0.625	−0.517	−0.598