ESS124
Prof.
Jin-Yi Yu
Physical Meanings
•The
thermal wind is a vertical shear in the geostrophic wind caused by a
horizontal temperature
gradient. Its name is a misnomer, because the thermal wind is not actually a wind, but rather a wind
gradient.
•The
vertical shear (including direction and speed) of geostrophic wind is related
to the
horizontal variation of temperature.
è The thermal
wind equation is an extremely useful diagnostic tool, which is often used to check analyses of the observed wind and
temperature fields for consistency.
èIt can
also be used to estimate the mean horizontal temperature advection in a
layer.
èThermal wind blows parallel to the isotherms with the warm
air to the right facing
downstream in the Northern Hemisphere.
