Geoscience Reference
In-Depth Information
FIGURE 9.3
(See color insert.)
Dominant. climate. indices. for. the. gridded. precipitation.
data,.determined.using.Maximum.Basic.Probability.Assignment.
Figure 9.2.have.been.categorized.into.areas.of.positive,.negative,.and.insigniicant.
correlation.. In. most. cases,. signiicant. correlation. varied. from. absolute. values. of.
about.0.20.to.0.40..Insigniicant.values.fell.between.-0.20.and.0.20..Although.not.
high.in.the.absolute.sense,.these.values.are.similar.to.other.values.reported.in.the.
literature. (van. Oldenborgh. and. Burgers. 2005).. It. should. also. be. noted. that. some.
of.the.highest.ρ-values.are.negative—this.does.not.necessarily.indicate.a.negative.
relationship.between.the.index.and.precipitation..All.of.the.circulation.indices.used.
here.have.both.negative.and.positive.values.depending.on.the.phase.of.the.climate.
mode.. Thus,. a. negative. correlation. value. might. mean. that. precipitation. amounts.
are.greater.when.a.climate.mode.is.in.its.negative.phase..The.meaning.of.the.phase.
varies. from. depending. on. the. mode. in. question,. thus. it. is. useful. to. consider. the.
absolute.value.of.correlation.when.evaluating.the.overall.importance.of.a.circula-
tion.index.
Correlation. between. gridded. precipitation. and. atmospheric. circulation. modes.
show. some. spatial. patterns. of. dominance;. however,. there. were. also. large. areas.
of. insigniicant. correlation. associated. with. each. circulation. index. (Figure 9.2)..
Signiicant. correlations. between. SOI. and. precipitation. were. found. over. most. of.
