Kelvin-Helmholtz billows superimposed on mesoscale rolls in stratocumulus

This NASA Worldview image shows Kelvin-Helmholtz (K-H) billows superimposed on mesoscale rolls in stratocumulus. The mesoscale rolls are oriented E-W, while the much shorter wavelength K-H billows are oriented WNW-ESE (at least toward the bottom of the image where the billows are most clearly seen).

The mesoscale rolls likely align with the shear vector across the PBL, whereas the billows likely align with the shear vector across the inversion atop the PBL. These two shear vectors need not be parallel.

KH_stratocumulus