Spatial and temporal scales of variability in Tropical Atlantic sea surface salinity from the SMOS and Aquarius satellite missions
Spatial and temporal scales of variability in Tropical Atlantic sea surface salinity from the SMOS and Aquarius satellite missions
Taking advantage of the spatially dense, multi-year time series of global Sea Surface Salinity (SSS) from two concurrent satellite missions, the spatial and temporal decorrelation scales of SSS in the Tropical Atlantic 30°N–30°S are quantified for the first time from SMOS and Aquarius observations. Given the dominance of the seasonal cycle in SSS variability in the region, the length scales are calculated both for the mean and anomaly (i.e. seasonal cycle removed) SSS fields. Different 7–10 days composite SSS products from the two missions are examined to explore the possible effects of varying resolution, bias corrections and averaging characteristics. With the seasonal cycle retained, the SSS field is characterized by strongly anisotropic spatial variability. Homogeneous SSS variations in the Tropics have the longest zonal scales of over ~ 2000 km and long temporal scales of up to ~ 70–80 days, as shown by both SMOS and Aquarius. The longest meridional scales, reaching over ~ 1000 km, are seen in the South Atlantic between ~ 10°–25°S, most discernible in Aquarius data. The longest temporal scales of SSS variability are reported by both satellites to occur in the North-West Atlantic region 15°–30°N, at the Southern end of the Sargasso Sea, with SSS persisting for up to 150–200 days. The removal of the seasonal cycle results in a noticeable decrease in the spatio-temporal decorrelation scales over most of the basin. Overall, with the exception of the differences in the South Atlantic, there is general agreement between the spatial and temporal scales of SSS from the two satellites and different products, despite differences in individual product calibration and resolution characteristics. These new estimates of spatio-temporal decorrelation scales of SSS improve our knowledge of the processes and mechanisms controlling the Tropical Atlantic SSS variability, and provide valuable information for a wide range of oceanographic and modelling applications.
Sea surface salinity variability, spatial and temporal decorrelation length scales, SMOS, Aquarius, Tropical Atlantic
418-430
Tzortzi, Eleni
eb21d805-0df9-4d09-aa1c-2deb9baa57a8
Srokosz, Meric A.
1e0442ce-679f-43f2-8fe4-9a0f0174d483
Gommenginger, Christine P.
f0db32be-34bb-44da-944b-c6b206ca4143
Josey, Simon A.
2252ab7f-5cd2-49fd-a951-aece44553d93
July 2016
Tzortzi, Eleni
eb21d805-0df9-4d09-aa1c-2deb9baa57a8
Srokosz, Meric A.
1e0442ce-679f-43f2-8fe4-9a0f0174d483
Gommenginger, Christine P.
f0db32be-34bb-44da-944b-c6b206ca4143
Josey, Simon A.
2252ab7f-5cd2-49fd-a951-aece44553d93
Tzortzi, Eleni, Srokosz, Meric A., Gommenginger, Christine P. and Josey, Simon A.
(2016)
Spatial and temporal scales of variability in Tropical Atlantic sea surface salinity from the SMOS and Aquarius satellite missions.
Remote Sensing of Environment, 180, .
(doi:10.1016/j.rse.2016.02.008).
Abstract
Taking advantage of the spatially dense, multi-year time series of global Sea Surface Salinity (SSS) from two concurrent satellite missions, the spatial and temporal decorrelation scales of SSS in the Tropical Atlantic 30°N–30°S are quantified for the first time from SMOS and Aquarius observations. Given the dominance of the seasonal cycle in SSS variability in the region, the length scales are calculated both for the mean and anomaly (i.e. seasonal cycle removed) SSS fields. Different 7–10 days composite SSS products from the two missions are examined to explore the possible effects of varying resolution, bias corrections and averaging characteristics. With the seasonal cycle retained, the SSS field is characterized by strongly anisotropic spatial variability. Homogeneous SSS variations in the Tropics have the longest zonal scales of over ~ 2000 km and long temporal scales of up to ~ 70–80 days, as shown by both SMOS and Aquarius. The longest meridional scales, reaching over ~ 1000 km, are seen in the South Atlantic between ~ 10°–25°S, most discernible in Aquarius data. The longest temporal scales of SSS variability are reported by both satellites to occur in the North-West Atlantic region 15°–30°N, at the Southern end of the Sargasso Sea, with SSS persisting for up to 150–200 days. The removal of the seasonal cycle results in a noticeable decrease in the spatio-temporal decorrelation scales over most of the basin. Overall, with the exception of the differences in the South Atlantic, there is general agreement between the spatial and temporal scales of SSS from the two satellites and different products, despite differences in individual product calibration and resolution characteristics. These new estimates of spatio-temporal decorrelation scales of SSS improve our knowledge of the processes and mechanisms controlling the Tropical Atlantic SSS variability, and provide valuable information for a wide range of oceanographic and modelling applications.
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Accepted/In Press date: February 2016
Published date: July 2016
Keywords:
Sea surface salinity variability, spatial and temporal decorrelation length scales, SMOS, Aquarius, Tropical Atlantic
Organisations:
Marine Systems Modelling, Marine Physics and Ocean Climate
Identifiers
Local EPrints ID: 387211
URI: http://eprints.soton.ac.uk/id/eprint/387211
ISSN: 0034-4257
PURE UUID: 43bf61a4-7b08-4e9a-bde0-ec92956f21c6
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Date deposited: 10 Feb 2016 16:42
Last modified: 14 Mar 2024 22:45
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Contributors
Author:
Eleni Tzortzi
Author:
Meric A. Srokosz
Author:
Christine P. Gommenginger
Author:
Simon A. Josey
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