Baroclinic eddies baroclinic instability Baroclinic Instability-"is an instability that arises in rofating, stratified fluids that are subject to a horizontal temperature gradient. density increasing Energetics: p→k low density density decreasing Mathematics: nigh density low temperature Linear Baroclinic Instability Linear baroclinic system- ■Eady's model(1949) Charney's model (1947) 授课教师：张洋11授课教师：张洋 11 Baroclinic eddies - baroclinic instability n Baroclinic Instability - “is an instability that arises in rotating, stratified fluids that are subject to a horizontal temperature gradient”. i i i i i i i i ) ) ⇥ ￾ A B C high density low density low temperature high temperature density increasing density decreasing Fig. 6.9 A steady basic state giving rise to baroclinic instability. Potential density de￾creases upwards and equatorwards, and the associated horizontal pressure gradient is balanced by the Coriolis force. Parcel ‘A’ is heavier than ‘C’, and so statically sta￾ble, but it is lighter than ‘B’. Hence, if ‘A’ and ‘B’ are interchanged there is a release of potential energy. From Vallis (2006) From Vallis (2006) n Mathematics: n Energetics: n Linear Baroclinic Instability n Linear baroclinic system PE KE n Eady’s model (1949) n Charney’s model (1947)