Tropical easterlies

From Glossary of Meteorology

tropical easterlies

(Also called subtropical easterlies.) A term applied to the trade winds when they are shallow and exhibit a strong vertical shear.

With this structure, the easterlies give way at about 1.5 km to the upper westerlies (antitrades), which are sufficiently strong and deep to determine cloudiness and weather. The tropical easterlies occupy the poleward margin of the Tropics in summer and can cover most of the tropical belt in winter.
Compare equatorial easterlies.