Equatorward shift of annual Rossby waves in the Equatorial Pacific Ocean

2015 ◽  
Vol 34 (1) ◽  
pp. 212-218 ◽  
Author(s):  
Xiao Ma ◽  
Che Sun
Keyword(s):  
Pacific Ocean ◽  
Rossby Waves ◽  
Equatorial Pacific ◽  
Equatorial Pacific Ocean

scholarly journals Interdecadal Sea Surface Temperature Variability in the Equatorial Pacific Ocean. Part I: The Role of Off-Equatorial Wind Stresses and Oceanic Rossby Waves

2007 ◽  
Vol 20 (11) ◽  
pp. 2643-2658 ◽  
Author(s):  
Shayne McGregor ◽  
Neil J. Holbrook ◽  
Scott B. Power
Keyword(s):  
Pacific Ocean ◽  
Wind Stress ◽  
Rossby Waves ◽  
Wave Reflection ◽  
Equatorial Pacific ◽  
Sea Surface ◽  
Thermocline Depth ◽  
Equatorial Pacific Ocean ◽  
Equatorial Thermocline ◽  
The Western Pacific

Abstract The Australian Bureau of Meteorology Research Centre CGCM and a linear first baroclinic-mode ocean shallow-water model (SWM) are used to investigate ocean dynamic forcing mechanisms of the equatorial Pacific Ocean interdecadal sea surface temperature (SST) variability. An EOF analysis of the 13-yr low-pass Butterworth-filtered SST anomalies from a century-time-scale CGCM simulation reveals an SST anomaly spatial pattern and time variability consistent with the interdecadal Pacific oscillation. Results from an SWM simulation forced with wind stresses from the CGCM simulation are shown to compare well with the CGCM, and as such the SWM is then used to investigate the roles of “uncoupled” equatorial wind stress forcing, off-equatorial wind stress forcing (OffEqWF), and Rossby wave reflection at the western Pacific Ocean boundary, on the decadal equatorial thermocline depth anomalies. Equatorial Pacific wind stresses are shown to explain a large proportion of the overall variance in the equatorial thermocline depth anomalies. However, OffEqWF beyond 12.5° latitude produces an interdecadal signature in the Niño-4 (Niño-3) region that explains approximately 10% (1.5%) of the filtered control simulation variance. Rossby wave reflection at the western Pacific boundary is shown to underpin the OffEqWF contribution to these equatorial anomalies. The implications of this result for the predictability of the decadal variations of thermocline depth are investigated with results showing that OffEqWF generates an equatorial response in the Niño-3 region up to 3 yr after the wind stress forcing is switched off. Further, a statistically significant correlation is found between thermocline depth anomalies in the off-equatorial zone and the Niño-3 region, with the Niño-3 region lagging by approximately 2 yr. The authors conclude that there is potential predictability of the OffEqWF equatorial thermocline depth anomalies with lead times of up to 3 yr when taking into account the amplitudes and locations of off-equatorial region Rossby waves.

scholarly journals Interdecadal Sea Surface Temperature Variability in the Equatorial Pacific Ocean. Part II: The Role of Equatorial/Off-Equatorial Wind Stresses in a Hybrid Coupled Model

2008 ◽  
Vol 21 (17) ◽  
pp. 4242-4256 ◽  
Author(s):  
Shayne McGregor ◽  
Neil J. Holbrook ◽  
Scott B. Power
Keyword(s):  
Pacific Ocean ◽  
Wind Stress ◽  
Rossby Waves ◽  
Coupled Model ◽  
Equatorial Region ◽  
Equatorial Pacific ◽  
Research Centre ◽  
Equatorial Pacific Ocean ◽  
Hybrid Coupled Model

Abstract Many modeling studies have been carried out to investigate the role of oceanic Rossby waves linking the off-equatorial and equatorial Pacific Ocean. Although the equatorial ocean response to off-equatorial wind stress forcing alone tends to be relatively small, it is clear that off-equatorial oceanic Rossby waves affect equatorial Pacific Ocean variability on interannual through to interdecadal time scales. In the present study, a hybrid coupled model (HCM) of the equatorial Pacific (between 12.5°S and 12.5°N) was developed and is used to estimate the magnitude of equatorial region variability arising from off-equatorial (poleward of 12.5° latitude) wind stress forcing. The HCM utilizes a reduced-gravity ocean shallow-water model and a statistical atmosphere derived from monthly output from a 100-yr Australian Bureau of Meteorology Research Centre (now the Centre for Australian Weather and Climate Research) coupled general circulation model integration. The equatorial region wind stress forcing is found to dominate both the interannual and interdecadal SST variability. The equatorial response to off-equatorial wind stress forcing alone is insufficient to initiate an atmospheric feedback that significantly amplifies the original equatorial region variability. Consequently, the predictability of equatorial region SST anomalies (SSTAs) could be limited to ∼1 yr (the maximum time it takes an oceanic Rossby wave to cross the Pacific Ocean basin in the equatorial region). However, the results also suggest that the addition of off-equatorial wind stress forcing to the HCM leads to variations in equatorial Pacific background SSTA of up to almost one standard deviation. This off-equatorially forced portion of the equatorial SSTA could prove critical for thresholds of El Niño–Southern Oscillation (ENSO) because they can constructively interfere with equatorially forced SSTA of the same sign to produce significant equatorial region ENSO anomalies.

Testing the iron hypothesis in ecosystems of the equatorial Pacific Ocean

Nature ◽  
1994 ◽  
Vol 371 (6493) ◽  
pp. 123-129 ◽  
Author(s):  
J. H. Martin ◽  
K. H. Coale ◽  
K. S. Johnson ◽  
S. E. Fitzwater ◽  
R. M. Gordon ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Equatorial Pacific ◽  
Equatorial Pacific Ocean

Interannual variability and dynamics of intraseasonal wind rectification in the equatorial Pacific Ocean

2018 ◽  
Vol 52 (7-8) ◽  
pp. 4351-4369 ◽  
Author(s):  
Xia Zhao ◽  
Dongliang Yuan ◽  
Guang Yang ◽  
Jing Wang ◽  
Hailong Liu ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Interannual Variability ◽  
Equatorial Pacific ◽  
Equatorial Pacific Ocean
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