'''DEFINITION'''

The northwestshelf_omi_tempsal_sst_trend product includes the Sea Surface Temperature (SST) trend for the European North West Shelf Seas over the period 1993-2020, i.e. the rate of change (°C/year). This OMI is derived from the CMEMS REP ATL L4 SST product (SST_ATL_SST_L4_REP_OBSERVATIONS_010_026), see e.g. the OMI QUID, http://marine.copernicus.eu/documents/QUID/CMEMS-OMI-QUID-ATL-SST.pdf, Mulet et al., 2018), which provided the SSTs used to compute the SST trend over the European North West Shelf Seas. This reprocessed product consists of daily (nighttime) interpolated 0.05° grid resolution SST maps built from the ESA Climate Change Initiative (CCI) (Merchant et al., 2019) and Copernicus Climate Change Service (C3S) initiatives. Trend analysis has been performed by using the X-11 seasonal adjustment procedure (see e.g. Pezzulli et al., 2005), which has the effect of filtering the input SST time series acting as a low bandpass filter for interannual variations. Mann-Kendall test and Sens’s method (Sen 1968) were applied to assess whether there was a monotonic upward or downward trend and to estimate the slope of the trend and its 95% confidence interval.

'''CONTEXT '''

Sea surface temperature (SST) is a key climate variable due to its role for climate variability and change (Deser et al., 2010; IPCC, 2021). SST is then essential to monitor and characterise the state of the global climate system (GCOS 2010). Long-term SST variability, from interannual to (multi-)decadal timescales, provides insight into the slow variations/changes in SST, i.e. the temperature trend (e.g., Pezzulli et al., 2005). In addition, on shorter timescales, SST anomalies become an essential indicator for extreme events, as e.g. marine heatwaves (Hobday et al., 2018).

'''CMEMS KEY FINDINGS'''

Over the period 1993-2020, the European North West Shelf Seas area experiences overall surface warming, particularly in the eastern part of the area such as the Kattegat region.

'''DOI (product):'''

https://doi.org/10.48670/moi-00276