Marine heatwave indices

Definition

Marine heatwave (MHW) indices have been defined to estimate sub-regional changes in MHW characteristics over the last four decades, as follows:

[MHW mean intensity]: annual mean of MHW intensity (above the mean)

[MHW maximum intensity]: annual maximum of MHW intensity (above the mean)

[MHW mean duration]: annual mean of MHW duration

[MHW frequency]: annual number of discrete events

[MHW total days]: annual total number of MHW days

Visualization

Every annual parameter is computed from the MHWs as detected using the Copernicus Marine Service satellite SST products. This section provides figures about:

Annual state for the last complete year (2D map in the Mediterranean Sea)

Sub-regional interannual and decadal variability since 1982 (time series and associated statistics)

Mean and linear trend over the longest available period since 1982 (2D maps in the Mediterranean Sea).

MHW mean intensity

Annual state (last year): map of annual mean intensity in the Mediterranean Sea

Sub-regional interannual/decadal variability (from 1982 to last year): timeseries of annual mean intensity (left) and associated statistics (right) in sub-regions

Mean and trend (1982-last year): maps of mean and linear trend of mean intensity in the Mediterranean Sea

MHW maximum intensity

Annual state (last year): map of annual maximum intensity in the Mediterranean Sea

Sub-regional interannual/decadal variability (from 1982 to last year): timeseries of annual maximum intensity (left) and associated statistics (right) in sub-regions

Mean and trend (1982-last year): maps of mean and linear trend of maximum intensity in the Mediterranean Sea

MHW mean duration

Annual state (last year): map of annual mean duration in the Mediterranean Sea

Sub-regional interannual/decadal variability (from 1982 to last year): timeseries of annual mean duration (left) and associated statistics (right) in sub-regions

Mean and trend (1982-last year): maps of mean and linear trend of mean duration in the Mediterranean Sea

MHW frequency

Annual state (last year): map of annual number of events in the Mediterranean Sea

Sub-regional interannual/decadal variability (from 1982 to last year): timeseries of annual number of events (left) and associated statistics (right) in sub-regions

Mean and trend (1982-last year): maps of mean and linear trend of number of events in the Mediterranean Sea

MHW total days

Annual state (last year): map of annual total days in the Mediterranean Sea

Sub-regional interannual/decadal variability (from 1982 to last year): timeseries of annual total days (left) and associated statistics (right) in sub-regions

Mean and trend (1982-last year): maps of mean and linear trend of MHW total days in the Mediterranean Sea