| Equation Name |
No. & Page |
Propagation Term |
Growth Term |
Comments |
| QGVE (Quasi-Geostrophic Vorticity Equation) |
(3.6a) p. 66 or
(4.2) p. 80 |
Horizontal
advection of absolute vorticity by geostrophic wind Also divergence term reinforces low
level advection but opposes upper level advection |
Divergence term: basically
it is vortex tube stretching. |
applies at any
level |
| EBVE (Equivalent Barotropic Vorticity Equation) |
(6.6)
p. 141 |
Horiz. advection
of vorticity at star level by star level wind. Has a
"divergence correction term" that slows long waves' retrograde motion |
none |
applies at star
level, roughly 500 mb. |
| BEBVE (Baroclinic Equivalent Barotropic Vorticity Equation) |
(7.3)
p. 161 or
(7.4a) p. 165 |
Horiz. advection
of vorticity at mean (or 500 mb) level by star (or 500 mb) level wind. Has
"divergence correction term" slows long waves' retrograde motion: ( s term ~  Ps/t) |
Horiz. advection
of "thermal vorticity" by the thermal wind: h min must be upstream from
upper level absolute vorticity max |
applies at mean
level or roughly 500 mb. thermal vorticity & thermal wind are greater when
temperature gradient is greater -- that is baroclinic instability |
| SPTE (Surface Pressure Tendency Equation) |
(4.11c) p. 97 |
Horiz. advection
of h by surface wind: storm moves parallel to the h contours by "reconstituing"
itself |
Horiz. advection
of 500 mb vorticity by 500 mb wind: upper level PVA |
applies only at
the surface. upper level vorticity max upstream from surface P min for growth |
| SDE (Sutcliffe's Development Equation) |
(8.7)
p. 183 |
Horiz. advection
of surface vorticity by thermal wind: storm moves parallel to the h contours from
direction of thermal wind. |
Horiz. advection
of "thermal vorticity" (which is mainly at the 500 mb level) by the thermal
wind. Roughly: upper level P"thermal" VA |
applies only at
the surface: h min upstream from surface level relative vorticity max for growth
links surface convergence to positive vorticity local change |