scholarly journals Satellites Reveal the Influence of Equatorial Currents and Tropical Instability Waves on the Drift of the Kon-Tiki in the Pacific

Oceanography ◽  
2004 ◽  
Vol 17 (4) ◽  
pp. 166-175 ◽  
Author(s):  
Richard Legeckis ◽  
Christopher Brown ◽  
Fabrice Bonjean ◽  
Eric Johnson
Keyword(s):  
Instability Waves ◽  
Tropical Instability Waves ◽  
The Pacific

The Role of the NECC in a Strong El Niño.

2020 ◽  
Author(s):  
David Webb
Keyword(s):  
Ocean Model ◽  
Warm Water ◽  
Ekman Transport ◽  
Global Ocean ◽  
Instability Waves ◽  
Tropical Instability Waves ◽  
The North ◽  
Ocean Science ◽  
The Pacific ◽  
North Equatorial Counter Current

<p>An analysis of archived data from the NEMO 1/12th degree global ocean model shows the importance of the North Equatorial Counter Current (NECC) in the development of the strong 1982–1983 and 1997–1998 El Niños.  The model results indicate that in a normal year the coreof warm water in the NECC is diluted by the surface Ekman transport, by geostrophic inflow and by tropical instability waves. During the development of the 1982–1983 and 1997–1998 El Niños, these processes had reduced effect at the longitudes of warmest equatorial temperatures. During the autumns of 1982 and 1997, the speed of the NECC was also increased by a stronger-than-normal annual Rossby wave and other changes in sea level in the western Pacific.  The resulting increased transport of warm water by the NECC resulted in water with temperatures above 28C reaching the eastern Pacific.  This appears to have been a major factor in moving the centre of deep atmospheric convection eastwards across the Pacific.</p><p>Note:  This is based on the paper published in Ocean Science.  An oral presentation is possible.</p>

scholarly journals On the role of the North Equatorial Counter Current during a strong El Niño

Ocean Science ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 633-660 ◽  
Author(s):  
David John Webb
Keyword(s):  
Ocean Model ◽  
Warm Water ◽  
Ekman Transport ◽  
Global Ocean ◽  
Instability Waves ◽  
Tropical Instability Waves ◽  
The North ◽  
The Pacific ◽  
North Equatorial Counter Current ◽  
Counter Current

Abstract. An analysis of archived data from the NEMO 1∕12th degree global ocean model shows the importance of the North Equatorial Counter Current (NECC) in the development of the strong 1982–1983 and 1997–1998 El Niños. The model results indicate that in a normal year the core of warm water in the NECC is diluted by the surface Ekman transport, by geostrophic inflow and by tropical instability waves. During the development of the 1982–1983 and 1997–1998 El Niños, these processes had reduced effect at the longitudes of warmest equatorial temperatures and to the west. During the autumns of 1982 and 1997, the speed of the NECC was also increased by a stronger-than-normal annual Rossby wave. The increased transport of warm water by the NECC due to these changes resulted in warm water reaching the far eastern Pacific and appears to have been a major factor in moving the centre of deep atmospheric convection eastwards across the Pacific.

Control of tropical instability waves in the Pacific

1995 ◽  
Vol 22 (19) ◽  
pp. 2581-2584 ◽  
Author(s):  
M. R. Allen ◽  
S. P. Lawrence ◽  
M. J. Murray ◽  
C. T. Mutlow ◽  
T. N. Stockdale ◽  
...  
Keyword(s):  
Instability Waves ◽  
Tropical Instability Waves ◽  
The Pacific

scholarly journals The influence of subseasonal wind variability on tropical instability waves in the Pacific

2001 ◽  
Vol 28 (10) ◽  
pp. 2041-2044 ◽  
Author(s):  
R. E. Benestad ◽  
R. T. Sutton ◽  
M. R. Allen ◽  
D. L. T. Anderson
Keyword(s):  
Instability Waves ◽  
Tropical Instability Waves ◽  
Wind Variability ◽  
The Pacific

scholarly journals Distinct 17- and 33-Day Tropical Instability Waves in Subsurface Observations*

2007 ◽  
Vol 37 (4) ◽  
pp. 855-872 ◽  
Author(s):  
John M. Lyman ◽  
Gregory C. Johnson ◽  
William S. Kessler
Keyword(s):  
Temporal Structure ◽  
Thermocline Depth ◽  
Subsurface Temperature ◽  
Instability Waves ◽  
Tropical Instability Waves ◽  
Meridional Velocity ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Half Degree ◽  
Temperature Time

Abstract Tropical instability waves (TIWs) within a half-degree of the equator in the Pacific Ocean have been consistently observed in meridional velocity with periods of around 20 days. On the other hand, near 5°N, TIWs have been observed in sea surface height (SSH), thermocline depth, and velocity to have periods near 30 days. Tropical Atmosphere–Ocean (TAO) Project moored equatorial velocity and temperature time series are used to investigate the spatial and temporal structure of TIWs during 3 years of La Niña conditions from 1998 through 2001. Along 140°W, where the TIW temperature and velocity variabilities are at their maxima, these variabilities include two distinct TIWs with periods of 17 and 33 days, rather than one broadbanded process. As predicted by modeling studies, the 17-day TIW variability is shown to occur not only in meridional velocity at the equator, but also in subsurface temperature at 2°N and 2°S, while the 33-day TIW variability is observed primarily in subsurface temperature at 5°N. These two TIWs, respectively, are shown to have characteristics similar to a Yanai wave/surface-trapped instability and an unstable first meridional mode Rossby wave. One implication of such a description is that the velocity variability on the equator is not directly associated with the dominant 33-day variability along 5°N.

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