Instructions for the Western North Pacific and Chinese Coastal Seas Marine Heatwave Dataset

This dataset provides marine heatwave (MHW) detection results for the Western North Pacific and Chinese Coastal Seas (WNPCC; 100°E–180°E, 0°–65°N) during both the historical period (1982–2014) and the future projection period (2015–2100). MHW events were identified according to the definition proposed by Hobday et al. (2016), in which a traditional MHW event is defined as an anomalous warming event where sea surface temperature (SST) exceeds the threshold value—corresponding to the 90th percentile of the climatological SST during the baseline period—for at least five consecutive days at an individual grid point.

The dataset includes MHW detection results derived from both observational and climate model data. The observational results are based on the Optimal Interpolated Sea Surface Temperature analysis data (OISSTV2) dataset, while the model-based results are derived from simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6). To ensure consistency, SST data from CMIP6 models with different spatial resolutions and the OISSTV2 dataset were uniformly interpolated onto a regular 1° × 1° grid prior to conducting historical MHW simulations and future projections.

For the historical period, the MHW dataset includes detection results from both OISST and CMIP6 data, with a total of 19 CMIP6 model datasets available. For the future period, the dataset contains MHW detection results derived from CMIP6 simulations under three Shared Socioeconomic Pathway (SSP) scenarios: SSP1-2.6, SSP2-4.5, and SSP5-8.5. These scenarios represent low-, intermediate-, and high-emission pathways, corresponding to increases in radiative forcing of 2.6, 4.5, and 8.5 W/m², respectively, by the end of the 21st century. The SSP2-4.5 and SSP5-8.5 scenarios each include projections from five climate models (GFDL-CM4, GFDL-ESM4, AWI-CM-1-1-MR, EC-Earth3-Veg, and EC-Earth3). Because GFDL-CM4 did not perform simulations under the SSP1-2.6 scenario, only four model datasets are available for this scenario.

The naming convention for the MHW detection results follows the format: “dataset name_detection start time_detection end time_threshold used”. For future projections, the corresponding SSP scenario identifier (i.e., SSP126, SSP245, or SSP585) is appended to the dataset name.

Each MAT file contains all detected MHW events within the study domain and study period for the corresponding dataset. For each individual MHW event, the following attributes are recorded: onset time (mhw_onset), end time (mhw_end), duration (mhw_dur), maximum intensity (int_max), mean intensity (int_mean), intensity variance (int_var), cumulative intensity (int_cum), and spatial location (xloc, yloc).