https://w3id.org/sciencelive/np/RAdIP7v2kJyOD-hRDIKdZkjMfFHkOIKdWoSnvAeGasU_s
.trig | .trig.txt | .jelly | .jelly.txt | .jsonld | .jsonld.txt | .nq | .nq.txt | .xml | .xml.txt
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sub:assertion {
sub:oliver-2018-mhw-days-replication-study a <https://w3id.org/sciencelive/o/terms/FORRT-Replication-Study>,
<https://w3id.org/sciencelive/o/terms/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";
<http://www.w3.org/2004/02/skos/core#related> <http://www.wikidata.org/entity/Q11850042>,
<http://www.wikidata.org/entity/Q125928>, <http://www.wikidata.org/entity/Q1507383>,
<http://www.wikidata.org/entity/Q56321065>;
<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/o/terms/hasDiscipline> <http://www.wikidata.org/entity/Q125928>;
<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/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. That test requires a Monte Carlo ensemble of synthetic
detections and was not performed.""";
<https://w3id.org/sciencelive/o/terms/targetsClaim> <https://w3id.org/sciencelive/np/RAGw-EZjva3ybpqWtY3loRFToZrm6GSMQqamvoe-e-JjE> .
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<https://orcid.org/0000-0002-1784-2920> <http://xmlns.com/foaf/0.1/name> "Anne Fouilloux" .
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dc:license <https://creativecommons.org/licenses/by/4.0/>;
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