The Relationship between Sea Surface Temperature and Thermocline Depth in the Eastern Equatorial Pacific

2004 ◽  
Vol 34 (3) ◽  
pp. 643-655 ◽  
Author(s):  
Hein Zelle ◽  
Gerrian Appeldoorn ◽  
Gerrit Burgers ◽  
Geert Jan van Oldenborgh
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Equatorial Pacific ◽  
Sea Surface ◽  
Eastern Pacific ◽  
Thermocline Depth ◽  
Subsurface Temperature ◽  
Central Pacific ◽  
Eastern Equatorial Pacific ◽  
Sst Anomalies

Abstract The time dependence of the local relation between sea surface temperature (SST) and thermocline depth in the central and eastern equatorial Pacific Ocean is analyzed for the period 1990–99, using subsurface temperature measurements from the Tropical Atmosphere–Ocean Array/Triangle Trans-Ocean Buoy Network (TAO/TRITON) buoy array. Thermocline depth anomalies lead SST anomalies in time, with a longitude-dependent delay ranging from 2 weeks in the eastern Pacific to 1 year in the central Pacific. The lagged correlation between thermocline depth and SST is strong, ranging from r > 0.9 in the east to r ≈ 0.6 at 170°W. Time-lagged correlations between thermocline depth and subsurface temperature anomalies indicate vertical advection of temperature anomalies from the thermocline to the surface in the eastern Pacific. The measurements are compared with the results of forced OGCM and linear model experiments. Using model results, it is shown that the delay between thermocline depth and SST is caused mainly by upwelling and mixing between 140° and 90°W. Between 170°E and 140°W the delay has a different explanation: thermocline depth anomalies travel to the eastern Pacific, where upwelling creates SST anomalies that in turn cause anomalous wind in the central Pacific. SST is then influenced by these wind anomalies.

Eastern Equatorial Pacific Forcing of ENSO Sea Surface Temperature Anomalies*

2008 ◽  
Vol 21 (22) ◽  
pp. 6070-6079 ◽  
Author(s):  
Xuebin Zhang ◽  
Michael J. McPhaden
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Wind Stress ◽  
Equatorial Pacific ◽  
Sea Surface ◽  
Eastern Pacific ◽  
Enso Cycle ◽  
Eastern Equatorial Pacific ◽  
Sst Anomaly ◽  
Sst Anomalies

Abstract Previous studies have described the impacts of wind stress variations in the eastern Pacific on sea surface temperature (SST) anomalies associated with the El Niño–Southern Oscillation (ENSO) phenomenon. However, these studies have usually focused on individual El Niño events and typically have not considered impacts on La Niña—the cold phase of the ENSO cycle. This paper examines effects of wind stress and heat flux forcing on interannual SST variations in the eastern equatorial Pacific from sensitivity tests using an ocean general circulation model over the period 1980–2002. Results indicate that in the Niño-3 region (5°N–5°S, 90°–150°W) a zonal wind stress anomaly of 0.01 N m−2 leads to about 1°C SST anomaly and that air–sea heat fluxes tend to damp interannual SST anomalies generated by other physical processes at a rate of about 40 W m−2 (°C)−1. These results systematically quantify expectations from previous event specific numerical model studies that local forcing in the eastern Pacific can significantly affect the evolution of both warm and cold phases of the ENSO cycle. The results are also consistent with a strictly empirical analysis that indicates that a wind stress anomaly of 0.01 N m−2 leads to ∼1°C SST anomaly in the Niño-3 region.

Cooling and freshening of the eastern equatorial Pacific over the last 2000 years

2020 ◽  
Author(s):  
Gerald Rustic ◽  
Athanasios Koutavas ◽  
Thomas Marchitto
Keyword(s):  
Stable Isotope ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Equatorial Pacific ◽  
Sea Surface ◽  
Eastern Pacific ◽  
Ice Age ◽  
Sea Surface Temperatures ◽  
Surface Temperatures ◽  
Eastern Equatorial Pacific

<p>Sea surface temperatures in the eastern equatorial Pacific exert powerful influence on the climate beyond the tropics through strong atmosphere-ocean coupling. Records of eastern Pacific sea surface temperatures are of vital importance for identifying the linkages between short-term climate variability and long-term climate trends. Here we reconstruct eastern equatorial Pacific sea surface temperature and salinity from paired trace metal and stable isotope analyses in foraminifera from a sediment core near the Galápagos Islands. Sea surface temperatures are correlated with reconstructed Northern and Southern hemisphere temperature records suggesting a common origin. We propose that this temperature signal originates in the extra-tropics and is transmitted to the eastern Pacific surface via its source waters. We find exceptions to this cooling during the Little Ice Age and during the last century, where notable sea surface temperature increases are observed. We calculate δ<sup>18</sup>O<sub>sw </sub>from paired stable isotope and trace element analyses and derive salinity, which reveals a significant trend toward fresher surface waters in the eastern equatorial Pacific. The overall trend toward cooler and fresher sea surface conditions is consistent with longer-term trends from both the Eastern and Western Pacific.</p>

scholarly journals Role of Mixed Layer Dynamics in Tropical North Atlantic Interannual Sea Surface Temperature Variability

2016 ◽  
Vol 29 (22) ◽  
pp. 8083-8101 ◽  
Author(s):  
Allyson Rugg ◽  
Gregory R. Foltz ◽  
Renellys C. Perez
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
North Atlantic ◽  
Sea Surface ◽  
Shortwave Radiation ◽  
Thermocline Depth ◽  
Equatorial Atlantic ◽  
Tropical North Atlantic ◽  
Sst Anomalies

Abstract This study examines the causes of observed sea surface temperature (SST) anomalies in the tropical North Atlantic between 1982 and 2015. The emphasis is on the boreal winter and spring seasons, when tropical Atlantic SSTs project strongly onto the Atlantic meridional mode (AMM). Results from a composite analysis of satellite and reanalysis data show important forcing of SST anomalies by wind-driven changes in mixed layer depth and shortwave radiation between 5° and 10°N, in addition to the well-known positive wind–evaporation–SST and shortwave radiation–SST feedbacks between 5° and 20°N. Anomalous surface winds also drive pronounced thermocline depth anomalies of opposite signs in the eastern equatorial Atlantic and intertropical convergence zone (ITCZ; 2°–8°N). A major new finding is that there is strong event-to-event variability in the impact of thermocline depth on SST in the ITCZ region, in contrast to the more consistent relationship in the eastern equatorial Atlantic. Much stronger anomalies of meridional wind stress, thermocline depth, and vertical turbulent cooling are found in the ITCZ region during a negative AMM event in 2009 compared to a negative event in 2015 and a positive event in 2010, despite SST anomalies of similar magnitude in the early stages of each event. The larger anomalies in 2009 led to a much stronger and longer-lived event. Possible causes of the inconsistent relationship between thermocline depth and SST in the ITCZ region are discussed, including the preconditioning role of the winter cross-equatorial SST gradient.

Mid-Pliocene equatorial Pacific sea surface temperature reconstruction: a multi-proxy perspective

2008 ◽  
Vol 367 (1886) ◽  
pp. 109-125 ◽  
Author(s):  
Harry J Dowsett ◽  
Marci M Robinson
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Temperature Reconstruction ◽  
Warm Pool ◽  
Equatorial Pacific ◽  
Sea Surface ◽  
Mean Annual Temperature ◽  
Meridional Heat Transport ◽  
Eastern Equatorial Pacific ◽  
Past Climate Change

The Mid-Pliocene is the most recent interval of sustained global warmth, which can be used to examine conditions predicted for the near future. An accurate spatial representation of the low-latitude Mid-Pliocene Pacific surface ocean is necessary to understand past climate change in the light of forecasts of future change. Mid-Pliocene sea surface temperature (SST) anomalies show a strong contrast between the western equatorial Pacific (WEP) and eastern equatorial Pacific (EEP) regardless of proxy (faunal, alkenone and Mg/Ca). All WEP sites show small differences from modern mean annual temperature, but all EEP sites show significant positive deviation from present-day temperatures by as much as 4.4°C. Our reconstruction reflects SSTs similar to modern in the WEP, warmer than modern in the EEP and eastward extension of the WEP warm pool. The east–west equatorial Pacific SST gradient is decreased, but the pole to equator gradient does not change appreciably. We find it improbable that increased greenhouse gases (GHG) alone would cause such a heterogeneous warming and more likely that the cause of Mid-Pliocene warmth is a combination of several forcings including both increased meridional heat transport and increased GHG.

scholarly journals Effects of Salinity Variability on Recent El Niño Events

Atmosphere ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 475 ◽  
Author(s):  
Hai Zhi ◽  
Rong-Hua Zhang ◽  
Pengfei Lin ◽  
Shiwei Shi
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
El Niño ◽  
El Nino ◽  
Equatorial Pacific ◽  
Sea Surface ◽  
Surface Salinity ◽  
Central Pacific ◽  
Salinity Variability ◽  
Central Equatorial Pacific

Ocean salinity variability provides a new way to study the evolution of the the El Niño-Southern Oscillation (ENSO). Comparisons between the salinity variation and related processes responsible for sea surface temperature anomaly (SSTA) were extensively examined for the two strong El Niño (EN) events in 1997/1998 and 2015/2016, and a special EN event in 2014/2015. The results show that the development of EN is significantly correlated with a sea surface salinity anomaly (SSSA) in the tropical western-central Pacific. In the spring of 1997 and 2015 with strong EN events, the western-central equatorial Pacific exhibited significant negative SSSA that propagated eastward to the west of the dateline. The negative SSSA induced increased barrier layer thickness (BLT) which enhanced sea surface temperature (SST) warming in the tropical central Pacific. In contrast, although a negative SSSA occurred during April of the 2014/2015 weak EN event in the western-central equatorial Pacific, this SSSA was mainly confined to between 160° E and 180° E without significant eastward movement, resulting in a weakened BLT thickening process and a weak modulation effect on SST. We also confirm that the surface forcing associated with fresh water flux (FWF: evaporation (E) minus precipitation (P)) plays a prominent role in the surface salinity tendency in the tropical Pacific during EN events. Moreover, the negative FWF anomaly leads a strong negative SSSA by two months. Compared with the two strong ENs, the early negative FWF anomaly in the weak 2014/2015 EN did not present distinct development and eastward propagation and weakened rapidly in the summer of 2015. We demonstrate that change in salinity can modulate the ENSO, and the variation of SSSA and associated physical processes in the tropical western-central Pacific and could be used as an indicator for predicting the development of ENSO.

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