Seasonal and interannual variations of sea surface carbon dioxide in the subtropical Indian Ocean

Abstract. The Arabian Sea plays an important role in the marine nitrogen cycle because of its pronounced mid-water oxygen minimum zone (OMZ) in which bio-available nitrate (NO3−) is reduced to dinitrogen gas (N2). As the nitrogen cycle can respond fast to climate-induced changes in productivity and circulation, the Arabian Sea sediments are an important palaeoclimatic archive. In order to understand seasonal and interannual variations in the nitrogen cycle, nutrient data were obtained from the literature published prior to 1993, evaluated, and compared with data measured during five expeditions carried out in the framework of the Joint Global Ocean Flux Study (JGOFS) in the Arabian Sea in 1995 and during a research cruise of RV Meteor in 2007. The data comparison showed that the area characterized by a pronounced secondary nitrite maximum (SNM) was by 63% larger in 1995 than a similarly determined estimate based on pre-JGOFS data. This area, referred to as the core of the denitrifying zone, showed strong seasonal and interannual variations driven by the monsoon. During the SW monsoon, the SNM retreated eastward due to the inflow of oxygen-enriched Indian Ocean Central Water (ICW). During the NE monsoon, the SNM expanded westward because of the reversal of the current regime. On an interannual timescale, a weaker SW monsoon decreased the inflow of ICW from the equatorial Indian Ocean and increased the accumulation of denitrification tracers by extending the residence time of water in the SNM. This is supported by palaeoclimatic studies showing an enhanced preservation of accumulative denitrification tracers in marine sediments in conjunction with a weakening of the SW monsoon during the late Holocene.

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Seasonal and interannual variations of the field of sea-surface temperature in the southwest Atlantic according to the data of satellite and contact measurements

Physical Oceanography ◽

10.1007/s11110-006-0034-9 ◽

2006 ◽

Vol 16 (5) ◽

pp. 299-311

Author(s):

Yu. V. Artamonov ◽

N. P. Bulgakov ◽

P. D. Lomakin ◽

E. A. Skripaleva

Keyword(s):

Surface Temperature ◽

Sea Surface Temperature ◽

Sea Surface ◽

Interannual Variations ◽

Southwest Atlantic ◽

Seasonal And Interannual Variations ◽

Contact Measurements

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Seasonal and Inter Annual Variation of Sea Surface Temperature in the Indonesian Waters

Forum Geografi ◽

10.23917/forgeo.v30i2.1530 ◽

2016 ◽

Vol 30 (2) ◽

pp. 120

Author(s):

Martono Martono

Keyword(s):

Surface Temperature ◽

Sea Surface Temperature ◽

Seasonal Variations ◽

Sea Surface ◽

Positive Anomaly ◽

Interannual Variations ◽

Arafura Sea ◽

Timor Sea ◽

Anomaly Analysis ◽

Seasonal And Interannual Variations

Sea surface temperature plays an important role in air-sea interactions. This research was conducted to understand seasonal and interannual variations of sea surface temperature in the Indonesian waters. The data used in this research was daily sea surface temperature in 1986 to 2015 which was obtained from the Physical Oceanography Distributed Active Archive Center - National Aeronautics and Space Administration. Method used in this study was the anomaly analysis. The result showed that the seasonal and interannual variations of sea surface temperature in the Indonesian waters varied. Seasonal variations of SST in the Makasar Strait, Sulawesi Sea, and Halmahera Sea were low. High seasonal variations of sea surface temperature occurred in the southern waters of Java, Timor Sea, Arafura Sea, and Banda Sea, which were allegedly due to the upwelling process. In addition, interannual variation of sea surface temperature in the Indonesian waters fluctuated. From 1986 to 2000, it showed a negative anomaly dominant. Meanwhile, from 2001 to 2015, it showed a positive anomaly dominant. The effect of Indian Ocean Dipole on the fluctuation of sea surface temperature in the Indonesian waters was stronger than ENSO. Within the last 30 years, the sea surface temperature in the Indonesian water indicated a rising trend. The highest sea surface temperature rise occurred in the Halmahera Sea that reached 0.66 OC/30 years and the lowest was in the Timor Sea of 0.36 OC/30 years.

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Variability of Sea Surface Salinity in the Southeastern Arabian Sea: Driving mechanisms and influence on the Arabian Sea mini Warm Pool

10.5194/egusphere-egu2020-21178 ◽

2020 ◽

Author(s):

Akhil Valiya Parambil ◽

Matthieu Lengaigne ◽

Jerome Vialard ◽

Krishnamohan Krishnapillai Sukumarapillai ◽

Keerthi Madhavan Girijakumari

Keyword(s):

Indian Ocean ◽

Seasonal Cycle ◽

Arabian Sea ◽

Vertical Mixing ◽

Warm Pool ◽

Sea Surface ◽

Interannual Variations ◽

Salinity Stratification ◽

Driving Mechanisms ◽

Southeastern Arabian Sea

<p>With sea surface temperatures (SST) exceeding 30&#730;C in May, the southeastern Arabian Sea (SEAS) hosts one of the warmest open ocean region globally, which appears to play an important role in the summer monsoon onset. Freshwater input from the Bay of Bengal precede the SEAS warm pool build-up by a few months, and are believed to influence its temperature through its impact on oceanic stability and vertical mixing of heat. SSS interannual variations in the SEAS region have not been extensively described before, and their potential feedback on the warm pool build-up and the monsoon are still debated. In the present study, we describe the SEAS SSS seasonal and interannual variability, its driving mechanisms and potential impact on the monsoon. To that end, we analyse experiments performed with a regional 25-km ocean model, both forced and coupled to a regional atmospheric model. The forced and coupled simulations both reproduce the main oceanic features in the SEAS region, including the salinity seasonal cycle and interannual variability. Winter salinity stratification inhibits the vertical mixing of heat, thereby warming the mixed layer by ~0.5&#176;C.month<sup>-1</sup>. This salinity-induced warming is however compensated by a salinity-induced cooling by air-sea fluxes. Salinity stratification indeed yields a thinner mixed layer which is more efficiently cooled by negative surface heat fluxes at this season. Overall, salinity has thus a negligible impact on the SST seasonal cycle. SEAS SSS interannual variations are largely remotely driven by the Indian Ocean Dipole (IOD), an indigenous interannual climate mode in the equatorial Indian Ocean. The IOD remotely impacts coastal currents along the Indian coastline, and hence modulates freshwater transport from the Bay of Bengal into the SEAS. This yields positive SSS anomalies in the SEAS during the boreal winter that follows positive IOD events. Those SSS anomalies however do not appear to significantly alter the interannual surface layer heat budget. Coupled model sensitivity experiments, in which the influence of haline stratification on vertical mixing is neglected, further confirm that the SEAS winter freshening does not significantly influence the SEAS warm-pool build-up nor the monsoon onset</p>

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Correlations between Interannual SST Oscillations and Modeled Swell Impacts on Turbulent Mixing*

Journal of Climate ◽

10.1175/jcli-d-15-0455.1 ◽

2015 ◽

Vol 29 (1) ◽

pp. 293-311 ◽

Cited By ~ 1

Author(s):

Yalin Fan ◽

W. Erick Rogers ◽

Tommy G. Jensen

Keyword(s):

Indian Ocean ◽

Southern Ocean ◽

Turbulent Mixing ◽

Southern Oscillation ◽

Wind Waves ◽

Sea Surface ◽

Interannual Variations ◽

The Indian Ocean ◽

Wave Models ◽

Sst Anomalies

Abstract The possibility of teleconnections between Southern Ocean swells and sea surface temperature (SST) anomalies on interannual time scales in the eastern Pacific Niño-3 region and southeastern Indian Ocean is investigated using numerical wave models. Two alternative parameterizations for swell dissipation are used. It is found that swell dissipation in the models is not directly correlated with large interannual variations such as El Niño–Southern Oscillation (ENSO) or the Indian Ocean dipole (IOD). However, using one of the two swell dissipation parameterizations, a correlation is found between observed SST anomalies and the modification of turbulent kinetic energy flux (TKEF) by Southern Ocean swells due to the damping of short wind waves: modeled reduction of TKEF is opposite in phase to the SST anomalies in the Niño-3 region, indicating a potential positive feedback. The modeled bimonthly averaged TKEF reduction in the southeastern Indian Ocean is also well correlated with the IOD mode.

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