Spatial patterns and evolution features of marine cold spells in the Arabian Sea during the past three decades

Marine Cold Spell (MCS) events are cold sea states with potentially devastating impacts on marine environments and ecosystems. In this study, we analyzed different MCS types with various severe categories in the Arabian Sea during 1994–2023. We found that all four types of MCS events shared a similar spatial pattern in terms of frequency, mean duration, mean intensity, and total days, but the frequency of 1-MCS events had a sharply decreasing trend compared with any other type of MCS events, indicating that ocean warming mainly led to the significant disappearance of short-period MCS events. Moreover, the MCS events in offshore Somalia had the highest occurring frequency, longest duration, largest intensity, and maximal total days, and were significantly different from those in other regions of the Arabian Sea. This is originated from that the cold–warm changes of the Somali current make larger fluctuations in the sea surface temperatures of the waters off Somalia, enhancing the occurring probability of MCS events, especially during the summers.