Indian Ocean Dipole modulated wave climate of eastern Arabian Sea

Anoop, T. R.; Kumar, V. Sanil; Shanas, P. R.; Glejin, Johnson; Amrutha, M. M.

doi:10.5194/osd-12-2473-2015

Cited by 9 publications

(14 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During negative IOD years surface winds are strong north to north-westerlies with wind vectors converging strongly over the TIP area. A study by Anoop et al (2016) had also found that the winds are north easterlies over the central west coast of India during the positive IOD years and as such they do not support coastal upwelling when compared to the negative IOD years. Lower SSTs and strong cyclonic surface winds can induce stronger than normal upwelling along CEAS as also evidenced by the higher than normal Chl_a concentrations during 1998 and 2010 (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…June-August is considered to be the developing phase of IOD whereas September-November is considered to be the mature phase (eg: Hong, 2008). Anoop et al, (2016) found that in the month of October different phased IOD events have significant influence on the wave climate off the central west coast of India compared to the northern and southern parts. The differential warming of the tropical oceans which can either increase or decrease the zonal temperature gradient can have severe implications on the general oceanic-atmospheric circulation pattern (eg: Swapna et al, 2014) and accordingly marine biological activity (Roxy et al, 2016).…”

mentioning

confidence: 99%

See 1 more Smart Citation

The influence of tropical Indian Ocean warming and Indian Ocean Dipole on the surface chlorophyll concentration in the eastern Arabian Sea

Sankar

Ramachandran

Ghomsi

et al. 2019

Preprint

View full text Add to dashboard Cite

<p><strong>Abstract.</strong> This study examines the role of increased Indian Ocean warming and positive Indian Ocean Dipole (IOD) events on the surface chlorophyll concentration in the Eastern Arabian Sea (EAS) during the period 1998 to 2014. Remotely sensed surface chlorophyll concentration &ndash; during the month of October when IOD strength is maximum &ndash; at three selected areas in the EAS, viz., the central eastern Arabian Sea (CEAS, 73°&thinsp;E&ndash;76°&thinsp;E, 13°&thinsp;N&ndash;18°&thinsp;N), south eastern Arabian Sea (SEAS, 74°&thinsp;E&ndash;77°&thinsp;E, 8°&thinsp;N&ndash;13°&thinsp;N) and the southern tip of India (TIP, 74°&thinsp;E&ndash;78°&thinsp;E, 5°&thinsp;N&ndash;8°&thinsp;N) shows a steady decreasing trend, though not statistically significant. The EAS also has a higher warming trend when compared to the western basin during the study period. Our analysis has shown that in the EAS, local surface winds, remote forcing by equatorial winds and the surface and sub-surface oceanic circulation features are less (respectively more) favorable for inducing coastal upwelling during positive (respectively negative) IOD years. The Dipole Mode Index (DMI) and surface chlorophyll concentration in the EAS is significantly and negatively correlated, pointing to the fact that in the event of occurrence of frequent positive IOD years under a global warming regime, the surface chlorophyll concentration is likely to decrease during fall.</p>

show abstract

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

The influence of tropical Indian Ocean warming and Indian Ocean Dipole on the surface chlorophyll concentration in the eastern Arabian Sea

Sankar

Ramachandran

Ghomsi

et al. 2019

Preprint

View full text Add to dashboard Cite

show abstract

“…Impact of ENSO and PDO on surface waves were investigated by Kumar et al (). However, across the North Indian Ocean, there have been limited studies on the impacts of regional atmospheric circulation patterns (Indian Ocean Dipole) on the wave climate (Anoop et al, ).…”

Section: Introductionmentioning

confidence: 99%

Long‐Term Variations in Nearshore Wave Climate and Littoral Drift at Ganpatipule Coast, Eastern Arabian Sea and its Link to Pacific Climate Variability

George

Kumar

2019

JGR Oceans

View full text Add to dashboard Cite

Nearshore wave characteristics and its variations at Ganpatipule coast, eastern Arabian Sea, for the past 4 decades (1979–2016) have been examined. The study is based on European Centre for Medium‐Range Weather Forecasts Re‐Analysis‐Interim wave data at ~50 m water depth and the nearshore wave parameters estimated using the numerical model Simulating WAves Nearshore, executed from the Delft3D dashboard considering shallow water wave propagation, wave setup, and breaking. The littoral drift is estimated based on bulk transport formula of the Coastal Engineering Research Centre with the input from the hydrodynamic module. The model shows good agreement with wave rider buoy measured wave parameters at 14‐m water depth. Anomalies of breaker height, period, and direction vary in the range of −0.35–0.4 m, −0.80–1 s, and − 16 to 12°, respectively during the study period. A detailed analysis of monthly variations of breaker height along the study region suggests a significant increasing trend during the Asian summer monsoon, whereas a decreasing trend is identified during the nonmonsoon period. The study region accounts for a northerly net transport of 3.9 × 105 m3 yr−1 with a significant increasing trend of 1,840 m3 yr−1. The strong wind field region along the central Arabian Sea (65–70°E and 15–20°N) gives a strengthened positive correlation (r > 0.7) with the littoral drift. Impacts of Pacific climate variability on interannual and decadal timescales are observed in the littoral drift rates.

show abstract

“…It highlights the role of IOD in wave climate variability induced by changes in the equatorial sea‐surface temperature and SLP. The changes in wind field over the Arabian Sea caused by the influence of IOD in turn can affect the generation or dissipation of wave field and cause decreased/increased northwest short period waves during positive/negative IOD phases (Anoop et al ., ).…”

Section: Introductionmentioning

confidence: 97%

“…Anoop et al . () linked the waves in the North IO (NIO) with IOD. Their study revealed an intrinsic mode of variability that has a significant role in driving climate oscillations in the ocean.…”

Section: Introductionmentioning

confidence: 99%

Dipole behaviour in maximum significant wave height over the Southern Indian Ocean

Gupta

Bhaskaran

Dash

2017

Intl Journal of Climatology

View full text Add to dashboard Cite

The study reports on existence of a dipole pattern in maximum significant wave height (MSWH) as well in mean significant wave height over the Southern Indian Ocean (SIO) based on analysis using 24 years of satellite observations. Analysis using quality checked daily altimeter data from nine satellite missions for entire Indian Ocean region revealed the spatio-temporal variability of observed dipole phenomena. Interestingly, the second empirical orthogonal function (EOF) mode (EOF2) in monthly and monthly anomaly MSWH data clearly shows the prevalence of dipole over the SIO having a period of 6 months for monthly dataset Principal Component (PC) leading to a 3 months oscillation. The EOF of monthly anomaly dataset analysis also exhibited a similar dipole pattern for the EOF2 mode having a period of 2.1 years. In addition, the study also considered seasonal EOF analysis for four austral seasons December-January-February (DJF), March-April-May (MAM), June-July-August (JJA), and September-October-November (SON). The EOF2 for all seasons exhibits a similar dipole pattern in SIO basin, except for the DJF months. Based on seasonal EOF analysis, the DJF and JJA EOF2s have similar dipole pattern that reverses its polarity because of wind variability for the MAM and SON EOF2s justifying 3 months dipole oscillation obtained for monthly datasets. The Radon transform is used to investigate the orientation of this dipole, and for the first time this method is used in the field of climatology to study orientation and the degree of polarity of a dipole pattern. Furthermore, the study investigated possible correlation of dipole with various proven climate indices establishing the fact that Southern Annular Mode Index (SAMI) showed a significant correlation. The other seasonal datasets also correlated well with SAMI, except DJF months that do not show the dipole pattern, and it had a good correlation with Nino3 index representing the El Nino Southern Oscillation Index.

show abstract

Indian Ocean Dipole modulated wave climate of eastern Arabian Sea

Cited by 9 publications

References 39 publications

The influence of tropical Indian Ocean warming and Indian Ocean Dipole on the surface chlorophyll concentration in the eastern Arabian Sea

The influence of tropical Indian Ocean warming and Indian Ocean Dipole on the surface chlorophyll concentration in the eastern Arabian Sea

Long‐Term Variations in Nearshore Wave Climate and Littoral Drift at Ganpatipule Coast, Eastern Arabian Sea and its Link to Pacific Climate Variability

Dipole behaviour in maximum significant wave height over the Southern Indian Ocean

Contact Info

Product

Resources

About