Thus, the amount of observational data in existence tends to be larger on Calendar days. Partial phases visible throughout Brazil, sub-Saharan and East Africa. Partial phases visible in the Pacific ocean, NW South America, Central America, continental U.S.A., western and southern parts of Canada. The dates are given in Note 1 under the Calendar.
Minimum program is PRWDs.
See Airglow and Aurora. During weeks with RWDs. S.T. Wu, Univ of Alabama, Huntsville Dept. The ISES coordinates the international aspects of the world days program and rapid data interchange. Similar Calendars have been issued annually beginning with the IGY, 1957-58, and have been published in various widely available scientific publications.