' . .
1200~
L
i
r
' :::r
400
8
Figure 4: Monthly-median discharge from the Piura River, which flows westward from the
Andes to the Pacific in northern Peru. Each dot represents a particular year month. The
dots for a particular calendar are scattered along the x axis to make them more visible
and the calendar year is repeated. The circles represent months during the 1982-83 El
Nino. From Deser and Wallace (1987) .
.-------~~--~~~-------------,
•
() "0' ()
•
120>'-----.:.00'=-----""',.---±:----+.-----:0=-0 - - '
Figure 5: The total rainfall for a network of more than 100 stations in the United States
summarized according to the lunar synodic (29.53 day) month for the period of record
1900-62. From Brier and Bradley (1964).
stratosphere, first pointed out by Reed (1960) and Ebdon (1961). The
time required for the wind to execute a full easterly/westerly cycle ranges
from slightly less than two years to about three years: hence the term
quasi-biennial oscillation (QBO). This phenomenon dominates time series
of zonal wind at levels between 10 and 100 hPa (17 and 30 km) at stations
within 10 degrees of the equator, as illustrated in Figs. 6 and 7.
In comparison to the equatorial stratospheric QBO, time series related
to ENSO such as the one shown in Fig. 8, exhibit a less regular behaviour,
as evidenced by the greater breadth of its spectral peak in Fig. 9. The
1200~
L
i
r
' :::r
400
8
Figure 4: Monthly-median discharge from the Piura River, which flows westward from the
Andes to the Pacific in northern Peru. Each dot represents a particular year month. The
dots for a particular calendar are scattered along the x axis to make them more visible
and the calendar year is repeated. The circles represent months during the 1982-83 El
Nino. From Deser and Wallace (1987) .
.-------~~--~~~-------------,
•
() "0' ()
•
120>'-----.:.00'=-----""',.---±:----+.-----:0=-0 - - '
Figure 5: The total rainfall for a network of more than 100 stations in the United States
summarized according to the lunar synodic (29.53 day) month for the period of record
1900-62. From Brier and Bradley (1964).
stratosphere, first pointed out by Reed (1960) and Ebdon (1961). The
time required for the wind to execute a full easterly/westerly cycle ranges
from slightly less than two years to about three years: hence the term
quasi-biennial oscillation (QBO). This phenomenon dominates time series
of zonal wind at levels between 10 and 100 hPa (17 and 30 km) at stations
within 10 degrees of the equator, as illustrated in Figs. 6 and 7.
In comparison to the equatorial stratospheric QBO, time series related
to ENSO such as the one shown in Fig. 8, exhibit a less regular behaviour,
as evidenced by the greater breadth of its spectral peak in Fig. 9. The