Spatial Variability and Trends of Marine Heat Waves in the Eastern Mediterranean Sea over 39 Years

Ibrahim, Omneya; Mohamed, Bayoumy; Nagy, Hazem

doi:10.3390/jmse9060643

Cited by 42 publications

(45 citation statements)

References 60 publications

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“…The period (14-years) that we have used to derive the temperature baseline, instead of using a longer dataset, may have underestimated the number of MHWs detected over the AIC Seas. However, the computed numbers and the durations of the MHWs agree with the levels derived from other studies for the broader Mediterranean Sea (e.g., the modeling study by Darmaraki et al [19]: an increase of 1.7 events/decade; satellite observations by Ibrahim et al [18]: an increase of 1.2 events/decade). Moreover, the high-resolution of the SST data (0.01 • ) provided significant information about the spatial distribution of both MHWs and the SST trends over the study domain, following a recommendation by Hobday et al [24].…”

Section: Summary and Discussionsupporting

confidence: 88%

“…The along-shore variability and interannual trends of the entire coastal region, which is of great social and ecological importance, will also be discussed for the first time. The findings of Inrahim et al [18], between 1982 and 2020, have shown that over the Eastern Mediterranean, the marine heat wave (MHW) frequency increased by 1.2 events per decade, with a maximum significant MHW SST event (6.35 • C above the 90th SST climatology threshold) in 2020. They related this increase to a decrease in the wind stress, an increase in the air temperature, and to an increase in the mean sea level pressure.…”

Section: Introductionmentioning

confidence: 99%

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Sea Surface Temperature Variability and Marine Heat Waves over the Aegean, Ionian, and Cretan Seas from 2008–2021

Androulidakis

Krestenitis

2022

JMSE

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The sea surface temperature (SST) is an important factor and indicator of the sea water quality, with various ecological and anthropogenic implications. We used high-resolution satellite-derived SST data, in tandem with field observations and long-term meteorological data, to investigate the spatial and interannual SST variability over the Aegean, Ionian, and Cretan (AIC) Seas during the recent 14-year period (2008–2021). Increasing trends were identified for most of the sub-basins of the AIC Seas. The numbers and durations (days) of the marine heat waves (MHWs) have significantly increased, especially during the last quadrennial period (2018–2021). Changes have been detected in both the maximum and minimum values; however, the trend of the mean annual values is mainly associated with the interannual increases in the lowest values (weaker minima during the cold seasons). The interannual variability and the increasing positive trends of the air temperature are very similar to the SST variations, showing a 5-to-10-day lag between the seasonal time series of the two parameters for all regions; however, extreme atmospheric events (e.g., cold fronts or heat waves) have a more direct impact on the SST variability (zero lag). MHWs were more frequent over the northern Aegean Sea, especially in Thermaikos Gulf, which is characterized as a “hot spot” for MHWs. MHWs were rarer over the southern regions, especially over the southeastern Aegean and Cretan Seas. A stratified upper ocean, controlled by buoyant brackish plumes, such as the Black Sea Waters (BSW) in the northern Aegean, may increase the heat storage capacity of the surface water masses, contributing to the further warming of the ocean. This was the case in the summer of 2021, which was a unique year for the AIC Seas, and especially for the northern Aegean, which revealed the highest SST values among all the study years. The satellite-derived observations of the 2008–2021 period showed increasing trends for all coastal waters, strong trend slopes for most of the coasts of the northern Aegean and central Ionian Seas, and milder trend slopes in the eastern Aegean.

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Section: Summary and Discussionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Sea Surface Temperature Variability and Marine Heat Waves over the Aegean, Ionian, and Cretan Seas from 2008–2021

Androulidakis

Krestenitis

2022

JMSE

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“…The authors also highlighted the strong spatial variability in SST trend estimations. Trend values over 1982-2020 have been estimated at 0.032 and 0.044 ± 0.002 • C/year as averages in the western and eastern Mediterranean, respectively (Juza and Tintoré, 2021), and at 0.033 ± 0.004 • C/year in the Ionian and Levantine Seas (Ibrahim et al, 2021). The rapid sea surface warming trend in this ocean basin has been associated with strong increase in MHW days, particularly during the last two decades since the beginning of the 20th century (Bensoussan et al, 2019;Ibrahim et al, 2021;Juza and Tintoré, 2021).…”

Section: Introductionmentioning

confidence: 96%

Sub-Regional Marine Heat Waves in the Mediterranean Sea From Observations: Long-Term Surface Changes, Sub-Surface and Coastal Responses

2022

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Society is facing climate-related challenges and impacts, such as marine heat wave (MHW) events that adversely affect ecosystems, threaten economies and strengthen storms by warming ocean waters. MHWs are substantially increasing in intensity, duration and frequency worldwide, particularly in the Mediterranean Sea, which responds rapidly to climate change. This study proposes a comprehensive analysis of MHWs in the different sub-regions of the Mediterranean, where the strong spatial variability requires focused attention, from surface to sub-surface and from open to coastal oceans. At surface, the MHW indices have dramatically increased over the last four decades from 1982 to 2020, with an unprecedented acceleration rate in recent years in all sub-regions. Besides the sub-regional features of surface MHWs, the propagation of such events into the ocean interior is also examined highlighting sub-regional and seasonal variability in the sub-surface ocean response. The resulting upper-ocean density stratification to these extreme events is enhanced in all sub-regions which would increase the degree of decoupling between surface and deep oceans causing changes in water masses and marine life. Finally, extremely warm events in coastal waters are also addressed through a case study in the Balearic Islands showing their higher intensity and occurrence in near-shore environment as well as the different response from surface to sub-surface that strongly depends on local features. In addition to this study, the Balearic Islands Coastal Observing and Forecasting System (SOCIB) has implemented a smart platform to monitor, visualize and share timely information on sub-regional MHWs, from event detection in real-time to long-term variations in response to global warming, to diverse stakeholders. Society-aligned ocean information at sub-regional scale will support the policy decision-making and the implementation of specific actions at local, national and regional scales, and thus contribute to respond to societal and worldwide environmental challenges.

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“…Regardless of the mechanisms that drive individual MHWs, there is a growing acceptance that anthropogenic climate change has raised the likelihood of recent MHWs dramatically, including the following occasions. Prominent occasions occurred over the Red Sea, especially: in its northern basin, as stated by Chaidez et al [5]; in the Gulf of Aqaba, as stated by Shaltout [6]; along the Mediterranean Sea including the central Ligurian Sea (Sparnocchia et al [2]), the central basin (Olita et al [7]) and the eastern basin (Ibrahim et al [8]); over the eastern Indian ocean, especially along the Western Australian coast (Pearce and Feng [9]) and across northern Australia (Benthuysen et al [10]); over the northeastern Pacific ocean (Bond et al [11]); over the northwestern Atlantic ocean (Chen et al [12]). These occasions resulted in significant environmental and financial impacts, including a reduced chlorophyll-a concentration (Bond et al [11]), continuous coral bleaching (Hughes et al [13]), the death of fish (Caputi et al [14]), mass mortality (Garrabou et al [15]), geographical and seasonal shifts of marine species (Mills et al [16]; Cavole et al [17]) and economic problems (Mills et al [16]).…”

Section: Introductionmentioning

confidence: 93%

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

Bawadekji

Tonbol

Ghazouani

et al. 2021

JMSE

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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.

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Spatial Variability and Trends of Marine Heat Waves in the Eastern Mediterranean Sea over 39 Years

Cited by 42 publications

References 60 publications

Sea Surface Temperature Variability and Marine Heat Waves over the Aegean, Ionian, and Cretan Seas from 2008–2021

Sea Surface Temperature Variability and Marine Heat Waves over the Aegean, Ionian, and Cretan Seas from 2008–2021

Sub-Regional Marine Heat Waves in the Mediterranean Sea From Observations: Long-Term Surface Changes, Sub-Surface and Coastal Responses

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

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