Vertical Variability of Near-Surface Salinity in the Tropics: Consequences for L-Band Radiometer Calibration and Validation

Hénocq, Claire; Boutin, Jacqueline; Reverdin, Gilles; Petitcolin, F.; Arnault, Sabine; Lattes, Philippe

doi:10.1175/2009jtecho670.1

Cited by 77 publications

(75 citation statements)

References 35 publications

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“…Table 1 shows the URLs where various datasets were accessed. SLS is defined here as the uppermost salinity measurement in a given profile as long as it is above 10 m, or a single bucket or thermosalinograph measurement. It differs from SSS which can be considered a skin value within 1 cm of the surface (Henocq et al, 2009;Yu, 2010).…”

Section: F M Bingham Et Al: the Seasonal Cycle Of Surface Layer Samentioning

confidence: 99%

Characteristics of the seasonal cycle of surface layer salinity in the global ocean

2012

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Abstract. The seasonal variability of surface layer salinity (SLS), evaporation (E), precipitation (P ), E − P , advection and vertical entrainment over the global ocean is examined using in situ salinity data, the National Centers for Environmental Prediction's Climate System Forecast Reanalysis and a number of other ancillary data. Seasonal amplitudes and phases are calculated using harmonic analysis and presented in all areas of the open ocean between 60 • S and 60 • N. Areas with large amplitude SLS seasonal variations include: the intertropical convergence zone (ITCZ) in the Atlantic, Pacific and Indian Oceans; western marginal seas of the Pacific; and the Arabian Sea. The median amplitude in areas that have statistically significant seasonal cycles of SLS is 0.19. Between about 60 • S and 60 • N, 37 % of the ocean surface has a statistically significant seasonal cycle of SLS and 75 % has a seasonal cycle of E −P . Phases of SLS have a bimodal distribution, with most areas in the Northern Hemisphere peaking in SLS in March/April and in the Southern Hemisphere in September/October.The seasonal cycle is also estimated for surface freshwater forcing using a mixed-layer depth climatology. With the exception of areas near the western boundaries of the North Atlantic and North Pacific, seasonal variability is dominated by precipitation. Surface freshwater forcing also has a bimodal distribution, with peaks in January and July, 1-2 months before the peaks of SLS. Seasonal amplitudes and phases calculated for horizontal advection show it to be important in the tropical oceans. Vertical entrainment, estimated from mixedlayer heaving, is largest in mid and high latitudes, with a seasonal cycle that peaks in late winter.The amplitudes and phases of SLS and surface fluxes compare well in a qualitative sense, suggesting that much of the variability in SLS is due to E − P . However, the amplitudes of SLS are somewhat different than would be expected and the peak of SLS comes typically about one month earlier than expected. The differences of the amplitudes of the two quantities is largest in such areas as the Amazon River plume, the Arabian Sea, the ITCZ and the eastern equatorial Pacific and Atlantic.

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Section: F M Bingham Et Al: the Seasonal Cycle Of Surface Layer Samentioning

confidence: 99%

Characteristics of the seasonal cycle of surface layer salinity in the global ocean

2012

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“…Six moorings, with time series longer than 100 days from June to December 2010 and with peak amplitude of 33 day SSS signals larger than 0.1, are selected for comparisons (Table 1). Only high quality flagged (flag 5 1) TAO SSS and SST [Henocq et al, 2010] TAO SSS at 1 m depth to TAO SSS at 20 m depth, considering days with no SST stratification to estimate the biases and assuming that the biases evolve linearly in time.…”

Section: 1002/2014jc009960mentioning

confidence: 99%

SMOSSea Surface Salinity signals of tropical instability waves

Yin

Boutin

Reverdin

et al. 2014

J. Geophys. Res. Oceans

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“…Ship salinity is also measured at a few meters depth. Prior to SMOS launch, Hénocq et al (2010) have shown that in rainy regions, in situ salinity measured at various depths between 1 m and 10 m differ by 0.1 to 0.5 in 20 % of the cases and that care should be taken for validating and interpreting satellite SSS in rainy regions. Actually, large freshenings (several tenths of salinity unit) can develop in the upper few meters of the ocean after a heavy rainfall, as clearly evidenced during the Tropical Oceans-Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE) Lukas, 1996, 1997).…”

Section: Introductionmentioning

confidence: 99%

Sea surface freshening inferred from SMOS and ARGO salinity: impact of rain

et al. 2013

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Abstract. The sea surface salinity (SSS) measured from space by the Soil Moisture and Ocean Salinity (SMOS) mission has recently been revisited by the European Space Agency first campaign reprocessing. We show that, with respect to the previous version, biases close to land and ice greatly decrease. The accuracy of SMOS SSS averaged over 10 days, 100 × 100 km 2 in the open ocean and estimated by comparison to ARGO (Array for Real-Time Geostrophic Oceanography) SSS is on the order of 0.3-0.4 in tropical and subtropical regions and 0.5 in a cold region. The averaged negative SSS bias (−0.1) observed in the tropical Pacific Ocean between 5 • N and 15 • N, relatively to other regions, is suppressed when SMOS observations concomitant with rain events, as detected from SSM/Is (Special Sensor Microwave Imager) rain rates, are removed from the SMOS-ARGO comparisons. The SMOS freshening is linearly correlated to SSM/Is rain rate with a slope estimated to −0.14 mm −1 h, after correction for rain atmospheric contribution. This tendency is the signature of the temporal SSS variability between the time of SMOS and ARGO measurements linked to rain variability and of the vertical salinity stratification between the first centimeter of the sea surface layer sampled by SMOS and the 5 m depth sampled by ARGO. However, given that the whole set of collocations includes situations with ARGO measurements concomitant with rain events collocated with SMOS measurements under no rain, the mean −0.1 bias and the negative skewness of the statistical distribution of SMOS minus ARGO SSS difference are very likely the mean signature of the vertical salinity stratification. In the future, the analysis of ongoing in situ salinity measurements in the top 50 cm of the sea surface and of Aquarius satellite SSS are expected to provide complementary information about the sea surface salinity stratification.

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Vertical Variability of Near-Surface Salinity in the Tropics: Consequences for L-Band Radiometer Calibration and Validation

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Cited by 77 publications

References 35 publications

Characteristics of the seasonal cycle of surface layer salinity in the global ocean

Characteristics of the seasonal cycle of surface layer salinity in the global ocean

SMOSSea Surface Salinity signals of tropical instability waves

Sea surface freshening inferred from SMOS and ARGO salinity: impact of rain

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