https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s/Head https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s http://www.nanopub.org/nschema#hasAssertion https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s/assertion https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s http://www.nanopub.org/nschema#hasProvenance https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s/provenance https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s http://www.nanopub.org/nschema#hasPublicationInfo https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s/pubinfo https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s http://www.w3.org/1999/02/22-rdf-syntax-ns#type http://www.nanopub.org/nschema#Nanopublication https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s/assertion https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s/oliver-2018-mhw-days-replication-study http://www.w3.org/1999/02/22-rdf-syntax-ns#type https://w3id.org/sciencelive/o/terms/FORRT-Replication-Study https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s/oliver-2018-mhw-days-replication-study http://www.w3.org/1999/02/22-rdf-syntax-ns#type https://w3id.org/sciencelive/o/terms/Replication-Study https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s/oliver-2018-mhw-days-replication-study http://www.w3.org/2000/01/rdf-schema#label Replication of the satellite-era marine heatwave day trend using ESA SST CCI and XMHW https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s/oliver-2018-mhw-days-replication-study http://www.w3.org/2004/02/skos/core#related http://www.wikidata.org/entity/Q11850042 https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s/oliver-2018-mhw-days-replication-study http://www.w3.org/2004/02/skos/core#related http://www.wikidata.org/entity/Q125928 https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s/oliver-2018-mhw-days-replication-study http://www.w3.org/2004/02/skos/core#related http://www.wikidata.org/entity/Q1507383 https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s/oliver-2018-mhw-days-replication-study http://www.w3.org/2004/02/skos/core#related http://www.wikidata.org/entity/Q56321065 https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s/oliver-2018-mhw-days-replication-study https://w3id.org/sciencelive/o/terms/hasDeviationDescription 1. Sea surface temperature source. ESA SST CCI Analysis v3.0 rather than NOAA OI SST, and a 1 degree analysis grid rather than the original's 0.25 degree grid. This is the intended independence of the replication, not an incidental difference. 2. Detection software. XMHW rather than the original authors' own implementation of the same published definition. 3. Longitude sampling. The ARCO reader takes bands 60 native cells wide starting every 64, so 0.2 degrees of longitude is skipped every 3.2 degrees and the analysis grid holds 336 of a possible 360 one-degree columns - 93.3 percent coverage. Measured effect on the headline statistic: plus or minus 0.64 days. 4. ENSO removal is fitted to deseasonalised anomalies. The original describes regressing daily sea surface temperatures onto the multivariate ENSO index. Applied literally to raw temperatures, 25 predictors spanning plus and minus twelve months can combine into an annual harmonic and absorb the seasonal cycle; in this implementation that accounted for 66 percent of the signal removed and more than doubled detected marine heatwave days, when removing ENSO should reduce them. Regressing the anomaly confines the fit to interannual variability. This is believed to be what the original intends rather than a departure from it. 5. ENSO index version. The original multivariate ENSO index of Wolter and Timlin, which the original paper cites and which NOAA last updated in December 2018, rather than the maintained MEI.v2 successor, which uses a different variable set and base period. 6. Annual sea surface temperature variance and skewness are computed on deseasonalised anomalies. At mid-latitudes the seasonal cycle is roughly 95 percent of daily variance, so computing these on raw temperatures measures seasonal amplitude rather than the variability that governs threshold exceedance. 7. The excess-trend significance test against a stochastic climate model was not performed, so the corresponding maps carry no significance hatching. https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s/oliver-2018-mhw-days-replication-study https://w3id.org/sciencelive/o/terms/hasDiscipline http://www.wikidata.org/entity/Q125928 https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s/oliver-2018-mhw-days-replication-study https://w3id.org/sciencelive/o/terms/hasMethodologyDescription Daily sea surface temperature from ESA SST CCI Analysis v3.0 was streamed from the Copernicus Marine Service ARCO store and area-averaged from its native 0.05 degree grid to a 1 degree analysis grid while streaming, covering 1 January 1982 to 31 December 2016. Cells with continuous sea ice were excluded, following the original's ice-exclusion rule. Marine heatwaves were detected with XMHW, an xarray implementation of the Hobday et al. (2016) definition, using the parameters the original states: 90th percentile threshold, minimum duration of five days, gaps shorter than three days merged, an 11-day window for the percentile, 31-day smoothing of the percentile, and a 1983-2012 baseline climatology. Marine heatwave days were attributed to the calendar year in which they fall; event duration and intensity were attributed to the year each event started, as the original specifies. Per-cell annual statistics were aggregated to a global mean weighted by the cosine of latitude, and trends were estimated with the Theil-Sen estimator with 95 percent confidence intervals, as in the original. To separate the secular trend from interannual variability, the analysis was repeated on a sea surface temperature series with the ENSO signature removed: daily anomalies at each cell were regressed onto the multivariate ENSO index with monthly leads and lags to plus and minus one year, and the fitted ENSO component subtracted. Detection on that series used the climatology and threshold derived from the original, unmodified series, so that events remain defined relative to real-world conditions. https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s/oliver-2018-mhw-days-replication-study https://w3id.org/sciencelive/o/terms/hasScopeDescription This study tests the claim's satellite-era component: the change in globally averaged annual marine heatwave days between 1982 and 2016, and the 1980s baseline level against which that change is expressed. The two supporting metrics the original reports alongside it — trends in marine heatwave frequency and duration — are also evaluated, since the claim states that the day-count increase follows from them. Out of scope: every pre-satellite element of the original paper. Its century-scale results (1925-1954 versus 1987-2016), the proxy reconstruction from monthly gridded SST, and the six century-long in situ station records are not tested here, because no independent daily global SST record exists before 1981 that could test them. The abstract's most-quoted figure — a 54 percent increase in marine heatwave days - belongs to that pre-satellite proxy analysis and is therefore not the claim under test. Also out of scope: the excess-trend attribution of Figure 3a-c, which asks whether marine heatwave trends exceed what mean sea surface temperature warming alone would produce. 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