Response of the sea surface temperature to heatwaves during the France 2022 meteorological summer

Abstract

Abstract. Summer 2022 was memorable and record-breaking, ranking as the second hottest summer in France since the beginning of the measurements, with a seasonal average of 22.7 °C. In particular, France experienced multiple record-breaking heat waves. As the main heat sink of the Earth system, the oceans are at the forefront of events of this magnitude, which enhance oceanic disturbances such as marine heat waves. In this study, we investigated French maritime basins sea surface temperature to determine the ability of satellite measurements to track the response of surface waters to these events. Despite some gaps in data availability, we showed that during the meteorological summer of 2022, the mean sea surface temperature was between 1.3 °C and 2.6 °C above the long-term average (1982–2011). A focus on the heat wave from 31 July to 13 August was carried out and showed a significant sea surface temperature response to the heat wave with maximum temperatures measured locally at 30.8 °C in the North-western Mediterranean sea. Beyond the response to intense surface air temperatures, the contribution of other atmospheric variables was not negligible. Thus, we have shown that France experienced an August with above-average surface solar radiation correlated with below-average total cloud cover and anomalies in the distribution and intensity of wind speeds. The response to these different contributions depends on the hydrodynamic conditions, in particular the tides that ensure turbulent mixing. This is why the response is more pronounced in the Mediterranean, where the absence of dynamic mixing (below-average surface wind speed) is associated with an absence of tides. Our results were in line with previous studies and we confirmed here that even if the Mediterranean is a climate change hotspot, all maritime front are affected by a warming of surface waters. Our study therefore demonstrated the need for an efficient and sustainable operational system combining polar orbiting and geostationary satellites to prevent the alterations that threaten the oceans in the context of climate change.

Evolution of marine heatwaves in warming seas: the Mediterranean Sea case study

“…It started on 11 May 2022, and persisted until December with two short temporal interruptions, and it seems to continue beyond the end of that year (Figure 4). This event is concomitant with a strong and long-lasting atmospheric heat wave that took place in the western Mediterranean in 2022, suggesting the atmospheric configuration as one of the likely drivers (Faranda et al, 2023;Guinaldo et al, 2023). A relevant aspect concerns the impact of detrending in the characteristics of the catalogued events.…”

Possible influences of spring Barents Sea ice shrinking on Chinese heat wave events

“…Additionally, in June 2022, the global average temperature was approximately 0.4 C higher than normal, and that in northern Russia, western Europe, and the United States exceeded greater than 2 C (European Centre for Medium-Range Weather Forecasts, https://www.ecmwf.int/en/about/ media-centre/news/2022/european-heatwaves-june-2022). The daily maximum temperatures (T max ) in Spain, France and Italy reached 40 C and broke historical records (Guinaldo et al, 2023). Persistent atmospheric circulations played an important role in explaining the heat wave intensity and frequency (Teng et al, 2013;Tomczyk & Sulikowska, 2018).…”

Response of two temperate scleractinian corals to projected ocean warming and marine heatwaves

“…During the period 2015–2019, exceptional thermal conditions and MHWs in the Mediterranean Sea resulted in five consecutive years of widespread mass mortality events of marine species [5]. Recently, in 2022, western parts of the Mediterranean Sea have experienced the second hottest summer since the beginning of measurements, the hottest year being 2003 [15]. In 2022, the anomaly of SST between 1.3 and 2.6°C above the long-term average (1982–2011), and temperatures up to 30.8°C were recorded in August in the northwestern Mediterranean Sea [15].…”

“…Recently, in 2022, western parts of the Mediterranean Sea have experienced the second hottest summer since the beginning of measurements, the hottest year being 2003 [15]. In 2022, the anomaly of SST between 1.3 and 2.6°C above the long-term average (1982–2011), and temperatures up to 30.8°C were recorded in August in the northwestern Mediterranean Sea [15]. These extreme thermal events cause a long-term decline in habitat-forming species including corals and gorgonians that are among the most affected benthic organisms by MHWs [5].…”