SCALING LAWS IN A TURBULENT BAROCLINIC INSTABILITY

This work provides an empirical investigation of scaling laws in a clo ud system generated and advected by a strong baroclinic instability. A n infrared satellite image with a spatial (horizontal) resolution of a bout 1 km has been analyzed. The presence of two sizeable and unmistak able scaling regions, one extending from 1 to 15 km and characterized by a power law with an exponent close to 1, the other stretching from 20 km up to 100 km and characterized by a power law with exponent clos e to 1/3, have been revealed by variogram analysis. These two scaling laws are in agreement with the idea of scale invariance of the turbule nt motion and also suggest the presence of a self-similar structure. T o explore this possibility, wavelet transform analysis at different sp atial scales has been used. Our findings are that self-similarity is p resent at the smallest scales, but this universal characteristic may b e masked by non-universal effects which influence the homogeneity of t he underlying turbulent motion. The implications of the two scaling ex ponents, 1 and 1/3, are also discussed.