General and Local Characteristics of Current Marine Heatwave in the Red Sea

Abstract

In the ocean, heat waves are vital climatic extremes that can destroy the ecosystem together with ensuing socioeconomic consequences. Marine heat waves (MHW) recently attracted public interest, as well as scientific researchers, which motivates us to analyze the current heat wave events over the Red Sea and its surrounding sea region (Gulf of Aden). First, a comprehensive evaluation of how the extreme Red Sea surface temperature has been changing is presented using 0.25° daily gridded optimum interpolation sea surface temperature (OISST, V2.1) data from 1982 to 2020. Second, an analysis of the MHW’s general behavior using four different metrics over the study area, together with a study of the role of climate variability in MHW characteristics, is presented. Finally, the main spatiotemporal characteristics of MHWs were analyzed based on three different metrics to describe MHW’s local features. Over the studied 39 years, the current results showed that the threshold of warm extreme sea surface temperature events (90th percentile) is 30.03 °C, providing an additional average thermal restriction to MHW threshold values (this value is changed from one grid to another). The current analysis discovered 28 separate MHW events over the Red+, extending from 1988 to 2020, with the four longest events being chosen as a study case for future investigation. For the effect of climate variability, our results during the chosen study cases prove that ENSO and ISMI do not play a significant role in controlling MHW characteristics (except the MHW intensity, which has a clear relation with ENSO/ISMI) on Red+. Moreover, the chlorophyll concentration decreases more significantly than its climatic values during MHW events, showing the importance of the MHW effect on biological Red Sea features. In general, the MHW intensity and duration exhibit a meridional gradient, which increases from north to south over the Red Sea, unlike the MHW frequency, which decreases meridionally.

Marine Heatwaves in the Red Sea and their Relationship to Different Climate Modes: A Case Study of the 2010 Events in the Northern Red Sea

“…Sea, of which 590 days (58%) occurred in the last decade. These results indicate that the rapid increase in SST in the Red Sea has caused a positive trend in MHWs in the region, and they also suggest that MHWs in the Red Sea are expected to increase in the future with global warming, which is consistent with the findings of (Bawadekji et al, 2021 and. A comparison then was made between the atmospheric variables and the annual MHW frequency to provide a general idea of the atmospheric conditions associated with the years with the highest MHW occurrence for the entire RS, NRS and SRS.…”

“…The MHWs of the NRS were longer and more intense than those of the SRS, while the MHWs of the SRS were characterized by their frequent occurrence. The same pattern of MHW distribution was also observed by (Bawadekji et al, 2021 andMohamed et al, 2021).…”

“…Due to the importance of the Red Sea, several studies have investigated its physical properties, especially SST, as it can serve as an indicator of the thermal stress caused by global warming, which has devastating effects on the rich and diverse marine life of the Red Sea (Raitsos et al, 2011;Barros et al, 2014;Chaidez et al, 2017;Karnauskas and Jones, 2018;Shaltout, 2019;Trisos et al, 2020;Liu and Yao, 2022). However, only a few studies that have investigated MHWs in the Red Sea (Genevier et al, 2019;Bawadekji et al, 2021;Mohamed et al, 2021), and up-to-date there are no studies have investigated the link between climate patterns and the occurrence of MHWs in the Red Sea region. Raitsos et al (2011) used satellite-derived SST to examine the spatiotemporal changes in Red Sea temperatures between 1985 and 2007 and concluded that the Red Sea is experiencing a strong warming that began in the mid-1990s and increased abruptly after 1994.…”

Reply on RC1

“…Using satellite sea surface temperature (SST) data from 1985 to 2015, they found that MHWs in the Red Sea can trigger coral bleaching when their SSTs exceed the 95 th percentile, when the climatological average is 30°C or higher, last for at least seven consecutive days and occur at shallow depths (< 150 m). Bawadekji et al (2021) studied the general and local characteristics of the marine heatwaves in the Red Sea. Their study concluded that the Red Sea exhibits a meridional gradient with decreasing average annual MHW intensity and MHW duration from north to south, and a meridional gradient with increasing average annual MHW frequency from north to south.…”

Sea Surface Temperature: From Observation to Applications

“…[8,9] study the recent evolution of MHWs in the Mediterranean and Red Seas, where their frequency and intensity have clearly increased in the last four decades. Finally, [10] analyzes the main characteristics of MHWs in the Red Sea.…”