Southern Europe and Western Asia Marine Heat Waves (SEWA-MHWs): a dataset based on macro events

Abstract

Abstract. Marine Heat Waves (MHWs) induce significant impacts on marine ecosystems. There is a growing need for knowledge about extreme climate events to better inform decision-makers on future climate-related risks. Here we present a unique observational dataset of MHWs macro events and their characteristics over the Southern Europe and Western Asian (SEWA) basins, named SEWA-MHWs dataset. The SEWA-MHWs dataset is derived from the European Space Agency (ESA) Climate Change Initiative (CCI) Sea Surface Temperature (SST) v2 dataset and it covers the 1981–2016 period. The methodological framework used to build the SEWA-MHWs dataset is the novelty of this work. Firstly, the MHWs detected in each grid point of the ESA CCI SST dataset are relative to a time-varying baseline climatology. Since intrinsic fluctuation and anthropogenic warming are redefining the mean climate, the baseline considers both the trend and time-varying seasonal cycle. Secondly, using a connected component analysis, MHWs connected in space and time are aggregated in order to obtain macro events. Basically, a macro event-based dataset is obtained from a pixel-based dataset without losing high resolution (i. e. pixel) information. SEWA-MHWs dataset can be used for many scientific applications. For example, we identified phases of the well-know MHW of summer 2003 and, taking advantage of statistical clustering methods, we identified the largest macro events in SEWA basins and we clustered them based on shared metrics and characteristics.