|Data: NCEP reanalysis monthly streamfunction
(250 and 925 hPa) on a 2.5 x 2.5 deg. lat/lon grid.
Base Period: 1971-2000
Data Source: NCEP
The plot indicates the anomaly in the monthly streamfunction
at 250 (top) and 925 hPa (bottom) standardized by dividing by the standard
deviation for the base period 1971-2000. Grey (unlabelled) contours
indicate the climatological value of the streamfunction. Contour
interval for anomalies is 0.5 standard deviations. Positive anomalies
shown in red; negative anomalies in blue. NCEP is an acronym
for the National Centers for Environmental Prediction, US.