Formation mechanisms of PNA-like teleconnection pattern in response to the Madden-Julian oscillation
Abstract
Formation mechanisms of PNA-like teleconnection pattern in response to the Madden-Julian oscillation (MJO) have been investigated with the GFDL dry model simulations. For this, the Rossby wave source (RWS) has been identified first and wave seeding has been performed using Rossby wave dispersion relationship. Results show that initial MJO phase 2-like diabatic forcing generates negative PNA-like pattern through negative RWS to the north of the enhanced convection over the equatorial Indian Ocean (IO) and positive RWS to the north of the suppressed convection over the equatorial western Pacific. It is of interest that the dibatic forcing over the IO generates another +RWS region at the exit of the jet stream through advection of the climatological relative vorticity by the northerly MJO winds. Ray tracing demonstrates explicit Rossby wave energy propagation over the PNA region. A series of simulations with different monopole forcing indicates that MJO phase-2 structure is most effective for the generation of -PNA pattern. The mechanisms for the surface warming over NA are discussed with the integration of the temperature equation and Rossby wave propagation.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.A11K0152S
- Keywords:
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- 3319 General circulation;
- ATMOSPHERIC PROCESSESDE: 3362 Stratosphere/troposphere interactions;
- ATMOSPHERIC PROCESSESDE: 3367 Theoretical modeling;
- ATMOSPHERIC PROCESSESDE: 3373 Tropical dynamics;
- ATMOSPHERIC PROCESSES