The ocean heat content in the northwest Indian Ocean region

Abstract

Ocean Heat Content (OHC) is crucial for understanding ocean dynamics. The Northwest Indian Ocean (NWIO) region, comprising the Southern Red Sea, the Gulf of Aden, the Arabian Sea, and the Equatorial North West Indian Ocean, is affected by various phenomena, such as upwelling, heat waves, and multi-layer exchange between the Red Sea and the Gulf of Aden. The spatial and temporal variability of these factors affects upper-layer OHC. OHC in the NWIO region has rarely been studied earlier. Therefore, this work would be beneficial in filling the knowledge gap and understanding the OHC of this region. The study displays the horizontal distributions of monthly OHC and yearly signal amplitudes, calculated as the difference between maximum and minimum values across all months, along with the monthly mean OHC patterns in the upper 100 m and 300 m layers of the NWIO, based on the available historical seawater temperature and salinity data from the World Data Centre (WDC-A, Washington D.C.), WDC-B (Moscow) and the Egyptian National Oceanographic Data Centre (ENODC). The region exhibited a similar pattern of monthly average OHC in the upper 100 and 300 m layers, except within the Equatorial North West Indian Ocean zone. In addition, the lower layer within the Red Sea exhibited a different pattern during the winter and transitional months. The NWIO region demonstrated homogeneous annual OHC signal amplitudes, except for the Arabian Sea, which has the highest annual amplitude at both layers.