Correlation between Zurich Sunspot Number and Prominence of Jupiter's Red Spot

Abstract

Graf, Smith and McDevitt1 have presented a graph which purports to show a correlation between the prominence of the Great Red Spot on Jupiter and the Zurich sunspot number between 1892 and 1947. They did not, however, quantitatively establish the significance of this correlation. More recently Argyle2 has shown the correlation coefficient from the data of Graf et al. to be 0.27 for the years 1892–1947, and from this concludes that the relationship is not established unless a better correlation is obtained. We have used and extended Peek's3 numerical rating of Red Spot prominence for the period 1892–1967 and have tested it for correlation with the Zurich sunspot number4,5. Our Red spot ratings for the years following 1947 (Table 1) are those compiled over the years by Mr Elmer J. Reese, using Peek's criteria. Standard statistical correlation methods were used, yielding a correlation coefficient of + 0.16 for the sixty-nine pairs. The probability is 0.15 that a correlation coefficient this large could result from chance alone. We may therefore conclude that the correlation level, and the that the correlation between Red Spot prominence and the Zurich sunspot number during the observed interval has not been established.