TY  - JOUR
AU  - SIMMONDS, IAN
AU  - LIM, EUN-PA
Y2  - 2014/05/22
Y1  - 2009
SN  - 1944–8007
UR  - http://hdl.handle.net/11343/32754
AB  - The maximum Eady growth rate measure of baroclinic instability is very commonly used in the literature. Its average is usually calculated directly from the time-mean flow. It is suggested here that this approach is not entirely suitable, but rather one should obtain the Eady growth rates at all relevant synoptic times and average these. It is found at the 850 hPa level in the Southern Hemisphere that the time-mean of the instantaneous rates exceed those calculated from the time-mean field over much of the mid and high latitudes, and the difference is even more marked at 500 hPa. At both levels the axes of the maxima Eady growth rates are displaced to the south. Some implications are discussed, including the need for caution when diagnosing changes in cyclone properties from changes in Eady growth rate calculated directly from the time-mean flow in climate change model simulations.
LA  - eng
PB  - American Geophysical Union
KW  - Eady growth rate
KW  - baroclinicity
KW  - Southern Hemisphere extratropical cyclones
T1  - Biases in the calculation of Southern Hemisphere mean baroclinic eddy growth rate
IS  - Geophysical Research Letters
VL  - 36
L1  - /bitstream/handle/11343/32754/289339_Biases%20in%20the%20calculation_Geophysical%20Research%20Letters.pdf?sequence=1&isAllowed=y
ER  -