A53F-3272:
The Response to MJO-like Forcing in a Nonlinear Shallow-Water Model
Abstract:
This study examines the response to Madden-Julian Oscillation (MJO)-like heat forcing in a nonlinearshallow-water model, including monopolar heating source traveling eastward with an around the world period of
48 days and dipolar heating with zonal wave period of 48 days, with zonal wave number 2 confined in longitude
to the MJO active regions. A jet localized in the Pacific is compared to a zonally uniform boreal basic flow. The
results show that the Rossby wave response downstream exhibits intensified quasi-stationary anomalies in
the Pacific jet exit region when the MJO-like heat forcing passes the Maritime Continent, in accord with the
observational analysis by Adames and Wallace (2014). The dynamical mechanism suggested in this study can
be used to interpret the intraseasonal MJO-Pacific North American pattern coherence and other extratropical
intraseasonal events.