Marine heatwaves

Marine heatwaves [MHW] occur when ocean water temperatures are much warmer than normal (above the 90th percentile of the climatological distribution and so-called marine heat spikes [MHS]) for at least five consecutive days (Hobday et al., 2016). The MHWs are computed using sea surface temperature (SST) from the daily near real-time (1/16º) and reprocessed (1/20º) satellite products in the Mediterranean Sea distributed by the Copernicus Marine Service (Pisano et al., 2016, Buongiorno Nardelli et al., 2013). The reference period chosen for the climatology is 1982-2015.

The daily bulletin provides daily map of MHS in the Mediterranean (for the last available day) and time series of sub-regional SST and MHS over the current year.

Annual MHW indices have been defined to estimate the long-term evolution of sub-regional MHW characteristics over the last four decades: total days, mean and maximum intensities (above the mean), mean duration and frequency.

Map of daily marine heat spike w.r.t. the daily 90th percentile climatology for the last available day (left). Timeseries of the sub-regional daily SST for the current year, the daily mean and 90th percentile climatologies, with marine heat spikes highlighted (right).

Map of the annual MHW total days for the last year (left) and time series of the sub-regional annual total days from 1982 to last year (right)

Map of the annual MHW mean intensity for the last year (left) and time series of the sub-regional annual mean intensity from 1982 to last year (right)

Map of the annual MHW maximum intensity for the last year (left) and time series of the sub-regional annual maximum intensity from 1982 to last year (right)

Map of the annual MHW mean duration for the last year (left) and time series of the sub-regional annual mean duration from 1982 to last year (right)

Map of the annual MHW frequency for the last year (left) and time series of the sub-regional annual frequency from 1982 to last year (right)