SMOSSea Surface Salinity signals of tropical instability waves

Yin, Xiaobin; Boutin, Jacqueline; Reverdin, Gilles; Lee, Tong; Arnault, Sabine; Martin, Nicolas

doi:10.1002/2014jc009960

Cited by 31 publications

(19 citation statements)

References 48 publications

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“…Consequently, even if TIWs are less active during an El Niño phase than in a La Niña phase, it was interesting to investigate the TIW propagation signature in SSH. Moreover, Yin et al (2014) and Lee et al (2012) also show the capability of monitoring TIWs by Aquarius and SMOS data. Lyman et al (2007) show that TIWs, which have a 33-day period, are associated with the first meridional-mode Rossby wave.…”

Section: Impact Of Assimilating Smos Data During Elmentioning

confidence: 94%

Data assimilation of Soil Moisture and Ocean Salinity (SMOS) observations into the Mercator Ocean operational system: focus on the El Niño 2015 event

Tranchant¹,

Rémy²,

Greiner³

et al. 2019

Ocean Sci.

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Abstract. Monitoring sea surface salinity (SSS) is important for understanding and forecasting the ocean circulation. It is even crucial in the context of the intensification of the water cycle. Until recently, SSS was one of the less observed essential ocean variables. Only sparse in situ observations, mostly closer to 5 m depth than the surface, were available to estimate the SSS. The recent satellite ESA Soil Moisture and Ocean Salinity (SMOS), NASA Aquarius SAC-D and Soil Moisture Active Passive (SMAP) missions have made it possible for the first time to measure SSS from space and can bring a valuable additional constraint to control the model salinity. Nevertheless, satellite SSS still contains some residual biases that must be removed prior to bias correction and data assimilation. One of the major challenges of this study is to estimate the SSS bias and a suitable observation error for the data assimilation system. It was made possible by modifying a 3D-Var bias correction scheme and by using the analysis of the residuals and errors with an adapted statistical technique. This article presents the design and the analysis of an observing system experiment (OSE) conducted with the 0.25∘ resolution Mercator Ocean global analysis and forecasting system during the El Niño 2015/16 event. The SSS data assimilation constrains the model to be closer to the near-surface salinity observations in a coherent way with the other data sets already routinely assimilated in an operational context. This also shows that the overestimation of E–P is corrected by data assimilation through salting in regions where precipitations are higher. Globally, the SMOS SSS assimilation has a positive impact in salinity over the top 30 m. Comparisons to independent salinity data sets show a small but positive impact and corroborate the fact that the impact of SMOS SSS assimilation is larger in the Intertropical Convergence Zone (ITCZ) and South Pacific Convergence Zone (SPCZ) regions. There is little impact on the sea surface temperature (SST) and sea surface height (SSH) error statistics. Nevertheless, the SSH seems to be impacted by the tropical instability wave (TIW) propagation, itself linked to changes in barrier layer thickness (BLT). Finally, this study helped us to progress in the understanding of the biases and errors that can degrade the SMOS SSS data assimilation performance.

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Section: Impact Of Assimilating Smos Data During Elmentioning

confidence: 94%

Data assimilation of Soil Moisture and Ocean Salinity (SMOS) observations into the Mercator Ocean operational system: focus on the El Niño 2015 event

Tranchant¹,

Rémy²,

Greiner³

et al. 2019

Ocean Sci.

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“…Satellite missions have revealed that SSS anomalies associated with eddies can be monitored for months near river outflows (Fournier, Vandemark, et al, 2017;Fournier, Vialard, et al, 2017) and large anomalies can be seen in the tropical Pacific Ocean following El Niño and La Niña events (Hasson et al, 2014. Studies have also shown that remotely sensed SSS in the tropical Pacific Ocean be used to trace mesoscale features such as tropical instability waves (Lee et al, 2012;Melnichenko et al, 2017;Yin et al, 2014) and heavy rainfall associated with large convective cells in the ITCZ (Supply et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Intraseasonal Variability of Surface Salinity in the Eastern Tropical Pacific Associated With Mesoscale Eddies

et al. 2019

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Strong variability in sea surface salinity (SSS) in the Eastern Tropical Pacific (ETPac) on intraseasonal to interannual timescales was studied using data from the Soil Moisture and Ocean Salinity, Soil Moisture Active Passive, and Aquarius satellite missions. A zonal wave number‐frequency spectral analysis of SSS reveals a dominant timescale of 50–180 days and spatial scale of 8°–20° of longitude with a distinct seasonal cycle and interannual variability. This intraseasonal SSS signal is detailed in the study of 19 individual ETPac eddies over 2010–2016 identified by their sea level anomalies, propagating westward at a speed of about 17 cm/s. ETPac eddies trap and advect water in their core westward up to 40° of longitude away from the coast. The SSS signatures of these eddies, with an average anomaly of 0.5‐pss magnitude difference from ambient values, enable the study of their dynamics and the mixing of their core waters with the surroundings. Three categories of eddies were identified according to the location where they were first tracked: (1) in the Gulf of Tehuantepec, (2) in the Gulf of Papagayo, and (3) in the open ocean near 100°W–12°N. They all traveled westward near 10°N latitude. Category 3 is of particular interest, as eddies seeded in the Gulf of Tehuantepec grew substantially in the vicinity of the Clipperton Fracture Zone rise and in a region where the mean zonal currents have anticyclonic shear. The evolution of the SSS signature associated with the eddies indicates the importance of mixing to their dissipation.

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“…Satellite measurements of sea surface salinity (SSS) from NASA's Aquarius mission (August 2011 to June 2015) and ESA's Soil Moisture and Ocean Salinity (SMOS) mission (January 2010 to present) have provided global SSS measurements that have been applied to a wide range of investigations including ocean dynamics, linkages with climate variability and the water cycle, and biogeochemistry [e.g., Lagerloef et al, 2013;Reul et al, 2014a]. For examples, the data have been used to study tropical instability waves [Lee et al, 2012Yin et al, 2014], SSS associated with river plumes and marginal seas [e.g., Grodsky et al, 2012;Gierach et al, 2013;Zeng et al, 2014;Fournier et al, 2016], intraseasonal SSS variations associated with the Madden-Julian Oscillation [Grunseich et al, 2013;Guan et al, 2014;Li et al, 2015], mesoscale eddies [e.g., Reul et al, 2014b], Rossby waves [Menezes et al, 2014], and interannual variations associated with climate modes [e.g., Qu and Yu, 2014;Du and Zhang, 2015]. The data have also been used to improve ocean state estimation and seasonal climate prediction [e.g., Köhl et al, 2014;Vinogradova et al, 2014;Toyoda et al, 2015;Hackert et al, 2014].…”

Section: Introductionmentioning

confidence: 99%

Consistency of Aquarius sea surface salinity with Argo products on various spatial and temporal scales

Lee

2016

Geophysical Research Letters

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Understanding the accuracies of satellite‐derived sea surface salinity measurements in depicting temporal changes and their dependence on spatiotemporal scales is important to applications, capability assessment, and future satellite mission design. This study quantifies the consistency between Aquarius Version 4 monthly gridded sea surface salinity (SSS) with two Argo‐based monthly gridded near‐surface salinity products for describing temporal changes on 1° × 1°, 3° × 3°, and 10° × 10° scales. Globally averaged standard deviation values for Aquarius‐Argo salinity differences on these three spatial scales are 0.16, 0.14, and 0.09 practical salinity unit (psu), compared to those between the two Argo products of 0.10, 0.09, and 0.04 psu. The consistency between Aquarius and Argo is similar to that between the two Argo products in the tropics for seasonal signals, and in the tropics and midlatitudes for nonseasonal signals. Therefore, the uncertainties of Argo products for various scales need to be considered in evaluating satellite SSS. Innovative satellite technologies are needed to improve high‐latitude satellite SSS measurements.

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SMOSSea Surface Salinity signals of tropical instability waves

Cited by 31 publications

References 48 publications

Data assimilation of Soil Moisture and Ocean Salinity (SMOS) observations into the Mercator Ocean operational system: focus on the El Niño 2015 event

Data assimilation of Soil Moisture and Ocean Salinity (SMOS) observations into the Mercator Ocean operational system: focus on the El Niño 2015 event

Intraseasonal Variability of Surface Salinity in the Eastern Tropical Pacific Associated With Mesoscale Eddies

Consistency of Aquarius sea surface salinity with Argo products on various spatial and temporal scales

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