Unraveling the Arabian Sea’s Thermal Pulse: Seasonal and Interannual SST Variability Amidst Climate Dynamics

This study investigates the spatio-temporal variability and long-term warming trends in sea surface temperature (SST) across the Arabian Sea from 2000 to 2019, using daily AVHRR satellite observations with a 1°x1° spatial resolution. Seasonal and interannual SST dynamics reveal patterns shaped by monsoonal processes and global climate phenomena, such as El Niño and La Niña. Wavelet spectrum analysis highlights periodic fluctuations and dominant frequencies associated with interannual climate variability, further emphasizing the influence of seasonal processes. Spring (MAM) exhibits the most pronounced interannual warming, particularly in the central and northern regions, while autumn (SON) demonstrates significant warming trends, especially in the southern basin. Monsoonal processes influence seasonal variability, with winter (DJF) cooling in the northern Arabian Sea and summer (JJA) upwelling along Oman and Somalia, resulting in localized cooling amidst broader warming trends in central and southern regions. Wavelet power spectra from critical regions, including the Gulf of Oman, Balochistan Coast, and Mumbai, indicate dominant periodicities of interannual warming, with variations corresponding to regional oceanographic processes. For instance, the Balochistan Coast displays the highest warming rate (0.0519°C/year), underscored by strong wavelet power at periodicities tied to El Niño–Southern Oscillation (ENSO) cycles. Similarly, the Gulf of Oman and Mumbai exhibit distinct spectral peaks, reflecting localized climate dynamics and variability. Regionally, the warming trend varies significantly. The Gulf of Aden (0.0181°C/year), Gulf of Oman (0.0164°C/year), and Gulf of Kutch (0.0269°C/year) exhibit moderate warming rates, while areas like the Balochistan Coast and South of Salalah (0.023°C/year) highlight significant localized warming. Southwestern Arabian Sea regions west of Kochi (0.0209°C/year) and Mangalore (0.0323°C/year) also demonstrate notable trends. In contrast, regions like Minicoy (0.0162°C/year) and the Male-Maldives area (0.0073°C/year) show relatively weaker warming. These findings underscore the critical role of spatial and seasonal variability in shaping SST changes and their implications for regional climate patterns, monsoonal behavior, marine ecosystems, and fisheries. The pronounced warming in key regions, coupled with insights from wavelet spectrum analysis, highlights the influence of localized oceanographic processes, such as upwelling, heat transport, and climate-induced variability. These results necessitate further study to assess future impacts and develop mitigation strategies for sensitive marine biodiversity and economic resources in the Arabian Sea .