ESS227
Prof. Jin-Yi Yu
Upper Tropospheric Flow Pattern
•Upper tropospheric flows are characterized by trough (low
pressure; isobars dip southward) and ridge (high
pressure; isobars bulge northward).
•The winds are in gradient wind balance at the bases of the trough
and ridge and are slower and faster,
respectively, than the geostrophic winds.
•Therefore, convergence and
divergence are created at different parts of the flow patterns, which contribute to the development of the low and high
systems.