4:15 PM - 4:30 PM
[AOS16-04] Spatiotemporal Variability and Long-Term Warming of Arabian Sea SST (2000–2019): Wavelet Analysis and Climate Influences
Keywords:Wavelet Spectral Analysis, AVHRR Dataset, Arabian Sea Warming, Monsoonal Dynamics, Sea Surface Temperature (SST)
This study examines the spatiotemporal variability and long-term trends in sea surface temperature (SST) across the Arabian Sea from 2000 to 2019, leveraging daily AVHRR satellite observations at a 1° × 1° spatial resolution. The analysis delineates seasonal and interannual SST fluctuations, modulated by monsoonal forcing and large-scale climate teleconnections, including El Niño–Southern Oscillation (ENSO). Wavelet spectral decomposition reveals dominant periodicities, elucidating the interplay between interannual climate variability and seasonal ocean-atmosphere interactions.
The SST warming signal exhibits distinct seasonal heterogeneity, with maximum interannual warming observed during boreal spring (MAM), particularly over the central and northern Arabian Sea, while significant autumnal (SON) warming is concentrated in the southern basin. The monsoonal regime exerts a fundamental control on SST dynamics, manifesting as boreal winter (DJF) cooling in the northern Arabian Sea and summer (JJA) upwelling-induced thermal depressions along the Oman-Somalia upwelling system. These localized cooling effects occur within an overarching framework of regional warming, particularly evident in the central and southern Arabian Sea.
Wavelet power spectra computed for key locations, including the Gulf of Oman, Balochistan Coast, and Mumbai, indicate dominant spectral signatures at interannual timescales, corresponding to ENSO-driven thermodynamic forcing and regional oceanographic variability. The Balochistan Coast exhibits the highest warming rate (0.0519°C/year), concomitant with significant spectral energy at ENSO-related periodicities, while the Gulf of Oman and Mumbai reveal distinctive spectral peaks reflecting localized thermodynamic and advective processes.
Spatially, the SST warming signal is heterogeneous, with moderate warming rates in the Gulf of Aden (0.0181°C/year), Gulf of Oman (0.0164°C/year), and Gulf of Kutch (0.0269°C/year), while more pronounced trends emerge along the Balochistan Coast (0.0519°C/year) and South of Salalah (0.023°C/year). Southwestern Arabian Sea regions, particularly west of Kochi (0.0209°C/year) and Mangalore (0.0323°C/year), exhibit notable warming trends, whereas Minicoy (0.0162°C/year) and the Male-Maldives region (0.0073°C/year) demonstrate relatively subdued warming.
These results underscore the intricate coupling between monsoonal processes, oceanographic dynamics, and large-scale climate variability in modulating SST trends. The pronounced warming in key regions, as revealed by wavelet spectrum diagnostics, underscores the role of regional thermodynamic and advective mechanisms in governing temperature anomalies. The findings emphasize the necessity for further high-resolution coupled ocean-atmosphere modeling efforts to elucidate the underlying drivers of observed warming and to assess potential implications for monsoonal variability, marine ecosystem resilience, and fisheries sustainability in the Arabian Sea.
The SST warming signal exhibits distinct seasonal heterogeneity, with maximum interannual warming observed during boreal spring (MAM), particularly over the central and northern Arabian Sea, while significant autumnal (SON) warming is concentrated in the southern basin. The monsoonal regime exerts a fundamental control on SST dynamics, manifesting as boreal winter (DJF) cooling in the northern Arabian Sea and summer (JJA) upwelling-induced thermal depressions along the Oman-Somalia upwelling system. These localized cooling effects occur within an overarching framework of regional warming, particularly evident in the central and southern Arabian Sea.
Wavelet power spectra computed for key locations, including the Gulf of Oman, Balochistan Coast, and Mumbai, indicate dominant spectral signatures at interannual timescales, corresponding to ENSO-driven thermodynamic forcing and regional oceanographic variability. The Balochistan Coast exhibits the highest warming rate (0.0519°C/year), concomitant with significant spectral energy at ENSO-related periodicities, while the Gulf of Oman and Mumbai reveal distinctive spectral peaks reflecting localized thermodynamic and advective processes.
Spatially, the SST warming signal is heterogeneous, with moderate warming rates in the Gulf of Aden (0.0181°C/year), Gulf of Oman (0.0164°C/year), and Gulf of Kutch (0.0269°C/year), while more pronounced trends emerge along the Balochistan Coast (0.0519°C/year) and South of Salalah (0.023°C/year). Southwestern Arabian Sea regions, particularly west of Kochi (0.0209°C/year) and Mangalore (0.0323°C/year), exhibit notable warming trends, whereas Minicoy (0.0162°C/year) and the Male-Maldives region (0.0073°C/year) demonstrate relatively subdued warming.
These results underscore the intricate coupling between monsoonal processes, oceanographic dynamics, and large-scale climate variability in modulating SST trends. The pronounced warming in key regions, as revealed by wavelet spectrum diagnostics, underscores the role of regional thermodynamic and advective mechanisms in governing temperature anomalies. The findings emphasize the necessity for further high-resolution coupled ocean-atmosphere modeling efforts to elucidate the underlying drivers of observed warming and to assess potential implications for monsoonal variability, marine ecosystem resilience, and fisheries sustainability in the Arabian Sea.