Influence of the Madden-Julian Oscillation on sea surface salinity in the Indian Ocean

Grunseich, Gary; Subrahmanyam, Bulusu; Argüez, Anthony

doi:10.1029/2011gl049047

Cited by 22 publications

(29 citation statements)

References 17 publications

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“…Grunseich et al . [] demonstrated using Simple Ocean Data Assimilation reanalysis that as the propagation of the MJO shifts seasonally, the SSS anomalies in the Indian Ocean fluctuate as well.…”

Section: Resultsmentioning

confidence: 99%

The Madden‐Julian oscillation detected in Aquarius salinity observations

Grunseich

Subrahmanyam

Wang

2013

Geophysical Research Letters

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[1] The Madden-Julian Oscillation (MJO) impacts a wide range of weather and climate phenomena. Current global coupled ocean-atmospheric general circulation models exhibit considerable shortcomings in representing and predicting the MJO, specifically its initiation, due to a lack of in situ observations. Here we show, for the first time, that the MJO propagation can be detected from the newly launched NASA Aquarius Salinity mission. The magnitude and extent of sea surface salinity (SSS) variations during the MJO is established, providing a useful tool for data assimilation into models to correctly represent both oceanic and atmospheric processes during intraseasonal variations. Salinity observation allows for atmospheric conditions to be inferred from freshwater flux, on which surface salinity is highly dependent. Increased observations of global SSS from the Aquarius mission will be particularly valuable in remote regions of the tropics and will increase our dynamical understanding and advance prediction of the MJO through model improvement.

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Section: Resultsmentioning

confidence: 99%

The Madden‐Julian oscillation detected in Aquarius salinity observations

Grunseich

Subrahmanyam

Wang

2013

Geophysical Research Letters

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“…Monsoon onset data were obtained from the India Meteorological Department, as well as previous studies (Ordoñez et al, ; Pai & Rajeevan, ). ENSO phases are based on the NOAA and NCEP Oceanic Niño Index and a previous study by Grunseich et al (). IOD phases are obtained from the Australian Bureau of Meteorology as annual phases.…”

Section: Methodsmentioning

confidence: 99%

“…Monsoon onset data for Table were obtained from the India Meteorological Department (IMD), as well as previous studies by Pai and Rajeevan () and Ordoñez et al (). El Niño Southern Oscillation (ENSO) phases were based on the NOAA and National Center for Environment Prediction (NCEP) Oceanic Niño Index (ONI) and a previous study by Grunseich et al (). Indian Ocean Dipole phases were obtained from the Australian Bureau of Meteorology as annual phases via http://www.bom.gov.au/climate/iod/.…”

Section: Acknowledgmentsmentioning

confidence: 99%

The Role of Salinity in the Southeastern Arabian Sea in Determining Monsoon Onset and Strength

2020

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In this study, we examine the role of freshwater transported from the Bay of Bengal into the southeastern Arabian Sea (SEAS) in determining both the timing of monsoon onset and the strength of the ensuing monsoon. To do this, we use a combination of satellite-derived salinity data and reanalysis products from 1980 to 2016 in order to discuss seasonal, interannual, subdecadal, and long-term decadal variability in various atmospheric and oceanic contributors such as ocean heat content, freshwater transport, ERA5 instantaneous moisture flux, mixed layer depth, and barrier layer thickness. The salt budget in the SEAS reveals the dominance of meridional freshwater advective transport that brings in variability in salinity and thus in salinity stratification, as well as in mixed layer processes. We find that these parameters exhibit the prevalence of a long-term decadal variability (with trends of increasing/decreasing phases over a 15-year duration) over which interannual (3-year trend) and intradecadal (7-year trend) variability trends are superimposed. The patterns of both the 3-and 7-year trends follow each other closely, and relatively high amplitudes are seen in the 3-year trends. The long-term decrease in moisture flux and freshwater transport into the SEAS along with a rise in ocean heat content over a 15-year duration after 1994 contributed to a lack of strong monsoons in recent years; the prevailing interannual and intradecadal variability in these parameters associated with the Indian Ocean Dipole and El Niño Southern Oscillation events favored weaker and normal monsoons after 1994. Plain Language SummaryThe timing and intensity of the southwest monsoon is difficult to forecast and has been the subject of a great deal of research. In particular, the genesis of a monsoon onset vortex over the southeastern Arabian Sea (SEAS) encompassing the Arabian Sea Mini Warm Pool has received increased attention for the role it plays on the onset of the southwest monsoon. In our study, we examine how the low salinity waters transported from the Bay of Bengal (both along the east coast of India and from the southern Bay of Bengal) into the SEAS region influence the strength and timing of the ensuing southwest monsoon. Our finding is that this low salinity water has a significant impact on barrier layer formation in the SEAS and the vertical thermal structure of the Arabian Sea Mini Warm Pool. Further examination of subdecadal, decadal, and long-period decadal trends from 1980 to 2016 shows that instantaneous moisture fluxes and zonal winds over the SEAS have decreased substantially, and barrier layer thickness has increased since 1994 in association with the increasing trend in ocean heat content and contributed to the lack of strong southwest monsoons after 1994.

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“…MJO events were identified based on the number of well-defined peaks in OLR that passed over 0 • , 90 • E. Positive peaks (anomalous clear sky conditions) in OLR were designated as the 0-day stage of the MJO propagation. The methodology from [5] and [11] was followed in constructing MJO composites of OLR and SSH. Morlet wavelet analysis of OLR and SSH data for the 1993-2008 time period was performed at 0 • , 90 • E due to this particular location experiencing strong MJO-related activity during boreal summer and winter and in order to understand the interaction of the MJO and Kelvin waves.…”

Section: Methodsmentioning

confidence: 99%

Detection of the Madden–Julian Oscillation in the Indian Ocean From Satellite Altimetry

Grunseich

Subrahmanyam

2013

IEEE Geosci. Remote Sensing Lett.

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The role of air-sea interaction on Madden-Julian oscillation (MJO) propagations across the tropical Indian Ocean is analyzed using integrated multimission satellite measurements of sea surface height and outgoing longwave radiation (OLR). MJO-related activity is observed in both parameters in the eastern equatorial Indian Ocean indicating a unique interaction in this region. In the eastern Indian Ocean, atmospheric conditions appear to aid in the creation of equatorial Rossby waves, while in the central and western Indian Ocean, different phases of oceanic Rossby wave propagations seem to have a strong influence on atmospheric conditions associated with the MJO. The downwelling phase of equatorial Rossby waves corresponds to a strengthening of OLR anomalies in extent and magnitude across the equatorial Indian Ocean, while the upwelling phase appears to weaken atmospheric MJO activity. This study improves climate research by identifying the MJO signal in altimetry data. Index Terms-Altimetry, Indian Ocean, Madden-Julian oscillation (MJO), sea surface height (SSH).

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Influence of the Madden-Julian Oscillation on sea surface salinity in the Indian Ocean

Cited by 22 publications

References 17 publications

The Madden‐Julian oscillation detected in Aquarius salinity observations

The Madden‐Julian oscillation detected in Aquarius salinity observations

The Role of Salinity in the Southeastern Arabian Sea in Determining Monsoon Onset and Strength

Detection of the Madden–Julian Oscillation in the Indian Ocean From Satellite Altimetry

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