Response of the atmosphere to a tropical Atlantic ocean temperature anomaly

Abstract Observed tropical Atlantic temperature anomalies for January 1963 have been used in a hemispheric model in an attempt to assess the extratropical effects of a tropical ocean temperature anomaly and to compare them with the results of previously reported experiments on tropical forcing. Falls of surface pressure were obtained over the warmed tropical water and extended north at least to 60°N over the east Atlantic, the northward limit of the falls varying considerably between three 80‐day experiment pairs as was to be expected from the tropical forcing experiments. The maximum amplitude of the mid‐latitude response (up to 7mb) was also consistent with that expected. One of the three experiment pairs produced an Atlantic pressure anomaly pattern similar to the average for the winter (1962–1963) in which the ocean anomaly was observed. The model is shown to give results which compared well with observations in winters with anomalous tropical Atlantic temperatures.