Notes on the wind flow at 50 mb in tropical and sub-tropical regions in January 1957 and January 1958



In January 1957 the mean 50 mb flow pattern was persistently E'ly over large areas near the Equator and this is compared with the flow pattern of January 1958 which was predominantly W'ly over much the same area. The mean vector winds for Canton Island for six Januarys show a remarkable 2-yr periodicity and suggest that either an E'ly or W'ly flow is equally likely to occur.