SOME INFERENCES FROM SATELLITE PICTURES OF TROPICAL DISTURBANCES

Abstract

The degree of organization and the size of the cloud patterns in TIROS pictures of tropical disturbances are good indicators of the maximum wind speed as observed by airplanes. The organization varies from unorganized bright cloud patterns, to highly organized spiral arrays of clouds with additional characteristic features, such as the sharp edge of cirrus clouds. Poorly organized clouds are associated with weak disturbances, the most highly organized ones with intense storms. In addition, within each category a relationship exists between the size of the cloud pattern and the maximum wind speed. Both the organization category and the size of the overcast cloud pattern are related statistically to the maximum wind speed, so that the maximum wind speed can be estimated from the picture of the storm alone. Tests with independent data show that a useful relationship has been obtained. Theoretical justification for the results obtained is necessary but is not yet available.