TY - JOUR
T1 - Rossby wave packets in baroclinic mean currents
AU - Chang, Ping
AU - Philander, S. G.H.
N1 - Funding Information:
Acknowledgements--Tiffs research was supported in part by the NOAA Equatorial Pacific Ocean Climate Studies (EPOCS) Program Grant NA87-EA-D00039 and NA84-EA-D00057 and by U.S. National Science Foundation Grant ATM82-18761. The authors wish to thank Drs Kirk Bryan and Isaac Held for reading the manuscript and making many useful suggestions.
PY - 1989/1
Y1 - 1989/1
N2 - A WKB description of the propagation of Rossby wave packets in a shallow water model of the tropical oceans indicates that the presence of the baroclinic mean currents can modify the characteristics of wave propagation significantly. For currents with weak latitudinal shear the effect of the current itself is less important than the effect of the associated variations in the depth of the thermocline, except near critical layers where waves are absorbed. For example, a westward current, and the associated shoaling of the thermocline towards the equator, can cause the speed of the long Rossby waves to decrease with decreasing latitude. (The speed increases towards the equator in the absence of mean currents.) Westward currents inhibit meridional propagation, but eastward currents enhance it. The amplification and decay of a wave packet as it propagates through a mean current are described in terms of these conservation of wave action. Implications of these results for the propagation of Rossby waves in the real ocean are discussed.
AB - A WKB description of the propagation of Rossby wave packets in a shallow water model of the tropical oceans indicates that the presence of the baroclinic mean currents can modify the characteristics of wave propagation significantly. For currents with weak latitudinal shear the effect of the current itself is less important than the effect of the associated variations in the depth of the thermocline, except near critical layers where waves are absorbed. For example, a westward current, and the associated shoaling of the thermocline towards the equator, can cause the speed of the long Rossby waves to decrease with decreasing latitude. (The speed increases towards the equator in the absence of mean currents.) Westward currents inhibit meridional propagation, but eastward currents enhance it. The amplification and decay of a wave packet as it propagates through a mean current are described in terms of these conservation of wave action. Implications of these results for the propagation of Rossby waves in the real ocean are discussed.
UR - http://www.scopus.com/inward/record.url?scp=0000337099&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0000337099&partnerID=8YFLogxK
U2 - 10.1016/0198-0149(89)90016-2
DO - 10.1016/0198-0149(89)90016-2
M3 - Article
AN - SCOPUS:0000337099
SN - 0198-0149
VL - 36
SP - 17
EP - 37
JO - Deep Sea Research Part A, Oceanographic Research Papers
JF - Deep Sea Research Part A, Oceanographic Research Papers
IS - 1
ER -