ENSO indices from sea surface salinity observed by Aquarius and Argo
نویسندگان
چکیده
Analysis of the first 26 months of data from the Aquarius satellite confirms the existence of a sharp sea surface salinity (SSS) front along the equator in the western equatorial Pacific. Following several earlier studies, we use the longitudinal location of the 34.8-psu isohaline as an index, termed Niño-S34.8, to measure the zonal displacement of the SSS front and consequently the eastern edge of the western Pacific warm pool. The on-going collection of the Array for Real-time Geostrophic Oceanography (ARGO) program data shows high correlations between Niño-S34.8 and the existing indices of El Niño, suggesting its potential important role in ENSO evolution. Further analysis of the ARGO data reveals that SSS variability in the southeastern tropical Pacific is crucial to identify the type of El Niño. A new SSS index, termed the southeastern Pacific SSS index (SEPSI), is defined based on the SSS variability in the region (0 –10 S, 150 –90 W). The SEPSI is highly correlated with the El Niño Modoki index, as well as the Trans-Niño index, introduced by previous studies. It has large positive anomalies during central Pacific El Niño or El Niño Modoki events, as a result of enhanced zonal sea surface temperature gradients between the central and eastern tropical Pacific, and can be used to characterize the type of El Niño. The processes that possibly control these SSS indices are also discussed.
منابع مشابه
Sea Surface Salinity And Barrier Layer Variability In The Equatorial Pacific As Seen From Aquarius And Argo
متن کامل
Coherent evidence from Aquarius and Argo for the existence of a shallow lowsalinity convergence zone beneath the Pacific ITCZ
Aquarius observations feature a prominent zonal sea-surface salinity (SSS) front that extends across the tropical Pacific between 2–10 N. By linking to Argo subsurface salinity observations and satellitederived surface forcing datasets, the study discovered that the SSS front is not a stand-alone feature; it is in fact the surface manifestation of a low-salinity convergence zone (LSCZ) located ...
متن کاملThe Impact of Dielectric Constant Model and Surface Reference on Differences between Smos and Aquarius Sea Surface Salinity
Two ongoing space missions share the scientific objective of mapping the global Sea Surface Salinity (SSS), yet their observations show significant discrepancies. ESA's Soil Moisture and Ocean Salinity (SMOS) and NASA's Aquarius use L-band (1.4 GHz) radiometers to measure emission from the sea surface and retrieve SSS. Significant differences in SSS retrieved by both sensors are observed, with ...
متن کاملSea surface temperature and salinity from French research vessels, 2001–2013
French Research vessels have been collecting thermo-salinometer (TSG) data since 1999 to contribute to the Global Ocean Surface Underway Data (GOSUD) programme. The instruments are regularly calibrated and continuously monitored. Water samples are taken on a daily basis by the crew and later analysed in the laboratory. We present here the delayed mode processing of the 2001-2013 dataset and an ...
متن کاملImpacts of Argo salinity in NCEP Global Ocean Data Assimilation System: The tropical Indian Ocean
[1] Salinity profiles collected by the International Argo Project (International Argo Project data are available at http://argo.jcommops.org) since 2000 provide us an unprecedented opportunity to study impacts of salinity data on the quality of ocean analysis, which has been hampered by a lack of salinity observations historically. The operational Global Ocean Data Assimilation System (GODAS) d...
متن کامل