Multidecadal Change of the South Pacific Gyre Circulation

2016 ◽  
Vol 46 (6) ◽  
pp. 1871-1883 ◽  
Author(s):  
Dean Roemmich ◽  
John Gilson ◽  
Philip Sutton ◽  
Nathalie Zilberman
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Ocean Circulation ◽  
South Pacific ◽  
Sea Surface Height ◽  
Sea Surface ◽  
Global Ocean ◽  
Depth Range ◽  
The South ◽  
South Pacific Gyre

AbstractMultidecadal trends in ocean heat and freshwater content are well documented, but much less evidence exists of long-term changes in ocean circulation. Previously, a 12-yr increase, 1993 to 2004, in the circulation of the South Pacific Subtropical Gyre interior was described. That analysis was based on differences between early Argo and 1990s hydrographic data and changes in sea surface height. Here, it is shown that the trend of increasing circulation continues through 2014, with some differences within the Argo decade (2005 to 2014). Patterns that indicate or are consistent with increasing equatorward transport in the eastern portion of the South Pacific Gyre are seen in Argo temperature and steric height, Argo trajectory velocity, altimetric sea surface height, sea surface temperature, sea level pressure, and wind stress. Between 2005 and 2014 the geostrophic circulation across 35°S, from 160°W to South America, was enhanced by 5 Sv (1 Sv ≡ 106 m3 s−1) of added northward flow. This was countered by a southward transport anomaly between the date line and 160°W. Corresponding temperature trends span the full 2000-m depth range of Argo observations. The 22-yr trend, 1993 to 2014, in sea surface height at 35°S, 160°W is 8 cm decade−1. Trends in sea surface temperature over 34 yr, 1981 to 2014, show a similar spatial pattern to that of sea surface height, with an increase of 0.5°C decade−1 at 35°S, 160°W. These multidecadal trends support the interpretation of the 40°S maximum in global ocean heat gain as resulting from anomalous wind forcing and Ekman convergence.

scholarly journals Observed modes of sea surface temperature variability in the South Pacific region

2017 ◽  
Vol 50 (3-4) ◽  
pp. 1129-1143 ◽  
Author(s):  
Ramiro I. Saurral ◽  
Francisco J. Doblas-Reyes ◽  
Javier García-Serrano
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
South Pacific ◽  
Temperature Variability ◽  
Sea Surface ◽  
Pacific Region ◽  
The South

scholarly journals The multifractal structure of satellite sea surface temperature maps can be used to obtain global maps of streamlines

2009 ◽  
Vol 6 (1) ◽  
pp. 129-151 ◽  
Author(s):  
A. Turiel ◽  
V. Nieves ◽  
E. Garcia-Ladona ◽  
J. Font ◽  
M.-H. Rio ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Turbulent Flows ◽  
Ocean Circulation ◽  
Singularity Analysis ◽  
Daily Basis ◽  
Dynamical Variable ◽  
Sea Surface ◽  
Global Ocean ◽  
Good Correspondence

Abstract. Nowadays Earth observation satellites provide information about many relevant variables of the ocean-climate system, such as temperature, moisture, aerosols, etc. However, to retrieve the velocity field, which is the most relevant dynamical variable, is still a technological challenge, specially in the case of oceans. New processing techniques, emerged from the theory of turbulent flows, have come to assist us in this task. In this paper, we show that multifractal techniques applied to new Sea Surface Temperature satellite products opens the way to build maps of ocean currents with unprecedented accuracy. With the application of singularity analysis, we show that global ocean circulation patterns can be retrieved in a daily basis. We compare these results with high-quality altimetry-derived geostrophic velocities, finding a quite good correspondence of the observed patterns both qualitatively and quantitatively. The implications of this findings from the perspective both of theory and of operational applications are discussed.

Decadal Spinup of the South Pacific Subtropical Gyre

2007 ◽  
Vol 37 (2) ◽  
pp. 162-173 ◽  
Author(s):  
D. Roemmich ◽  
J. Gilson ◽  
R. Davis ◽  
P. Sutton ◽  
S. Wijffels ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
World Ocean ◽  
South Pacific ◽  
Sea Surface Height ◽  
Subtropical Gyre ◽  
Sea Surface ◽  
The South ◽  
Maximum Increase ◽  
Large Spatial Scale ◽  
Dynamic Height

Abstract An increase in the circulation of the South Pacific Ocean subtropical gyre, extending from the sea surface to middepth, is observed over 12 years. Datasets used to quantify the decadal gyre spinup include satellite altimetric height, the World Ocean Circulation Experiment (WOCE) hydrographic and float survey of the South Pacific, a repeated hydrographic transect along 170°W, and profiling float data from the global Argo array. The signal in sea surface height is a 12-cm increase between 1993 and 2004, on large spatial scale centered at about 40°S, 170°W. The subsurface datasets show that this signal is predominantly due to density variations in the water column, that is, to deepening of isopycnal surfaces, extending to depths of at least 1800 m. The maximum increase in dynamic height is collocated with the deep center of the subtropical gyre, and the signal represents an increase in the total counterclockwise geostrophic circulation of the gyre, by at least 20% at 1000 m. A comparison of WOCE and Argo float trajectories at 1000 m confirms the gyre spinup during the 1990s. The signals in sea surface height, dynamic height, and velocity all peaked around 2003 and subsequently began to decline. The 1990s increase in wind-driven circulation resulted from decadal intensification of wind stress curl east of New Zealand—variability associated with an increase in the atmosphere’s Southern Hemisphere annular mode. It is suggested (based on altimetric height) that midlatitude gyres in all of the oceans have been affected by variability in the atmospheric annular modes on decadal time scales.

scholarly journals Evaluation of the South Pacific Convergence Zone in IPCC AR4 Climate Model Simulations of the Twentieth Century

2011 ◽  
Vol 24 (6) ◽  
pp. 1565-1582 ◽  
Author(s):  
Josephine R. Brown ◽  
Scott B. Power ◽  
Francois P. Delage ◽  
Robert A. Colman ◽  
Aurel F. Moise ◽  
...  
Keyword(s):  
Twentieth Century ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Interannual Variability ◽  
South Pacific ◽  
Sea Surface ◽  
South Pacific Convergence Zone ◽  
Convergence Zone ◽  
The South ◽  
Model Simulations

Abstract Understanding how the South Pacific convergence zone (SPCZ) may change in the future requires the use of global coupled atmosphere–ocean models. It is therefore important to evaluate the ability of such models to realistically simulate the SPCZ. The simulation of the SPCZ in 24 coupled model simulations of the twentieth century is examined. The models and simulations are those used for the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC). The seasonal climatology and interannual variability of the SPCZ is evaluated using observed and model precipitation. Twenty models simulate a distinct SPCZ, while four models merge intertropical convergence zone and SPCZ precipitation. The majority of models simulate an SPCZ with an overly zonal orientation, rather than extending in a diagonal band into the southeast Pacific as observed. Two-thirds of models capture the observed meridional displacement of the SPCZ during El Niño and La Niña events. The four models that use ocean heat flux adjustments simulate a better tropical SPCZ pattern because of a better representation of the Pacific sea surface temperature pattern and absence of cold sea surface temperature biases on the equator. However, the flux-adjusted models do not show greater skill in simulating the interannual variability of the SPCZ. While a small subset of models does not adequately reproduce the climatology or variability of the SPCZ, the majority of models are able to capture the main features of SPCZ climatology and variability, and they can therefore be used with some confidence for future climate projections.

scholarly journals Are Sea Surface Temperature satellite measurements reliable proxies of lagoon temperature in the South Pacific?

2017 ◽  
Vol 199 ◽  
pp. 117-124 ◽  
Author(s):  
Simon Van Wynsberge ◽  
Christophe Menkes ◽  
Romain Le Gendre ◽  
Teuru Passfield ◽  
Serge Andréfouët
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
South Pacific ◽  
Sea Surface ◽  
The South ◽  
Satellite Measurements

scholarly journals The multifractal structure of satellite sea surface temperature maps can be used to obtain global maps of streamlines

Ocean Science ◽  
2009 ◽  
Vol 5 (4) ◽  
pp. 447-460 ◽  
Author(s):  
A. Turiel ◽  
V. Nieves ◽  
E. Garcia-Ladona ◽  
J. Font ◽  
M.-H. Rio ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Turbulent Flows ◽  
Ocean Circulation ◽  
Singularity Analysis ◽  
Daily Basis ◽  
Dynamical Variable ◽  
Sea Surface ◽  
Global Ocean ◽  
Good Correspondence

Abstract. Nowadays Earth observation satellites provide information about many relevant variables of the ocean-climate system, such as temperature, moisture, aerosols, etc. However, to retrieve the velocity field, which is the most relevant dynamical variable, is still a technological challenge, specially in the case of oceans. New processing techniques, emerged from the theory of turbulent flows, have come to assist us in this task. In this paper, we show that multifractal techniques applied to new Sea Surface Temperature satellite products opens the way to build maps of ocean currents with unprecedented accuracy. With the application of singularity analysis, we show that global ocean circulation patterns can be retrieved in a daily basis. We compare these results with high-quality altimetry-derived geostrophic velocities, finding a quite good correspondence of the observed patterns both qualitatively and quantitatively; and this is done for the first time on a global basis, even for less active areas. The implications of this findings from the perspective both of theory and of operational applications are discussed.

scholarly journals Impact of projected sea surface temperature biases on tropical cyclones projections in the South Pacific

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
C. Dutheil ◽  
M. Lengaigne ◽  
M. Bador ◽  
J. Vialard ◽  
J. Lefèvre ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Tropical Cyclones ◽  
South Pacific ◽  
Sea Surface ◽  
The South
Sign in / Sign up

Export Citation Format

Share Document