100
Chapter 6: Analysing the Boreal Summer Relationship
Figure 6.1: Top four diagrams ((a) and (b)): EOFs p" (derived from
all seasons, 1901-80 data) and time eoeflicients a,,(t) for k = 2,3 and
t = all JAS-seasons 1949 - 1990. Smooth line is low pass filter (see text).
These two EOFs are statistieally distinet aeeording to the test of North et
al. (1982), but see diseussion of effeetive sampIe size for the test in FolIand
et al. (1991). p2 represents 7.8% of varianee and p3 3.8%.
Bottom two diagrams (e): 2nd Varimax-rotated EOF piv derived from the
raw EOFs p4 to p13, and its time series a~(t). Plt represents 2.5% oE the
original variance. Contour map units are in thousands.
7~r---~--~----~--~----,
(a)
-7.1 1.-__ ......... __ - - ' ____ .......... __ --1-__ ----'
llMt
''''
, .
1m
,...
'IU
-I
-..I
-3
llMt
'111
''''
'171
,. ,",
4
I
2
I
0
-I
-..I
-3
llMt
,MI
,tu
"11
'"
,tH
Chapter 6: Analysing the Boreal Summer Relationship
Figure 6.1: Top four diagrams ((a) and (b)): EOFs p" (derived from
all seasons, 1901-80 data) and time eoeflicients a,,(t) for k = 2,3 and
t = all JAS-seasons 1949 - 1990. Smooth line is low pass filter (see text).
These two EOFs are statistieally distinet aeeording to the test of North et
al. (1982), but see diseussion of effeetive sampIe size for the test in FolIand
et al. (1991). p2 represents 7.8% of varianee and p3 3.8%.
Bottom two diagrams (e): 2nd Varimax-rotated EOF piv derived from the
raw EOFs p4 to p13, and its time series a~(t). Plt represents 2.5% oE the
original variance. Contour map units are in thousands.
7~r---~--~----~--~----,
(a)
-7.1 1.-__ ......... __ - - ' ____ .......... __ --1-__ ----'
llMt
''''
, .
1m
,...
'IU
-I
-..I
-3
llMt
'111
''''
'171
,. ,",
4
I
2
I
0
-I
-..I
-3
llMt
,MI
,tu
"11
'"
,tH