The time-longitude map was created from five months (1 October 1992-28 February 1993) of 0.5 deg x 0.5 deg resolution daily PHC maps. Each one day by 0.5 deg longitude point in the time-longitude map is color coded according to the value of the meridional summation between 20 deg S and 20 deg N of daily PHC values > 25%. The pattern is color coded at thresholds such that light dark blue represents less than 2 counts, light blue 2-9, green 10-19, yellow, 20-29 and red 30 or more counts. Patterns illustrated in the time-longitude map indicate the gross evolution and zonal migration of large areas of cold cloudiness across the longitudinal range 80 deg E to 160 deg W. Three episodes of the intraseasonal oscillation over the west Pacific are included.
A postscript version of this map is also available.