270
C)
model
65H
55N
SON
~
40N
~
30M
25M
2011
Figure 2: continued: c) Spatial distribution of correlation coefficients of the index time
series shown in (a) and 500 hPa height anomalies over the Pacific and North America.
2.2 Observational data
Various observational data sets will be used to describe the decadal variability observed. A short description of these data is given below. The data
were available at monthly intervals. Sea surface temperature (SST) data
were obtained from the SST data set of the British Meteorological Office
(UKMO) which is referred to as the "GISST" data set, covering the period
1949-1991, and 700 hPa height data were provided by the Climate Analysis Center. The latter were available for the Northern Hemisphere and
the period 1950-1991. Near surface air temperature over North America
was obtained from an update of the Climate Research Unit (CRU) product
(Jones et al. (1986)). This record will be used back to 1866. Inspection
of the individual monthly maps for the era showed a surprising amount of
information in the regions wherein the North Pacific decadal mode, that
we shall discuss in the next section, has maximum variance. So we have
some confidence in the results for the whole period 1866-1992. Rainfall, in
gridded field format, was also provided courtesy of the CRU (cf Hulme and
Jones (1993)). Comparison of these data with the US divisional data and
C)
model
65H
55N
SON
~
40N
~
30M
25M
2011
Figure 2: continued: c) Spatial distribution of correlation coefficients of the index time
series shown in (a) and 500 hPa height anomalies over the Pacific and North America.
2.2 Observational data
Various observational data sets will be used to describe the decadal variability observed. A short description of these data is given below. The data
were available at monthly intervals. Sea surface temperature (SST) data
were obtained from the SST data set of the British Meteorological Office
(UKMO) which is referred to as the "GISST" data set, covering the period
1949-1991, and 700 hPa height data were provided by the Climate Analysis Center. The latter were available for the Northern Hemisphere and
the period 1950-1991. Near surface air temperature over North America
was obtained from an update of the Climate Research Unit (CRU) product
(Jones et al. (1986)). This record will be used back to 1866. Inspection
of the individual monthly maps for the era showed a surprising amount of
information in the regions wherein the North Pacific decadal mode, that
we shall discuss in the next section, has maximum variance. So we have
some confidence in the results for the whole period 1866-1992. Rainfall, in
gridded field format, was also provided courtesy of the CRU (cf Hulme and
Jones (1993)). Comparison of these data with the US divisional data and