@prefix this: . @prefix sub: . @prefix np: . @prefix rdf: . @prefix prov: . @prefix npx: . @prefix dc: . @prefix xsd: . sub:Head { this: a np:Nanopublication; np:hasAssertion sub:assertion; np:hasProvenance sub:provenance; np:hasPublicationInfo sub:pubinfo . } sub:assertion { sub:langhovde-meltwater-acceleration-study a , ; "Reproduction and partial replication of Sugiyama et al. (2026): meltwater, basal pressure and ice speed at Langhovde Glacier"; , , , ; """- Smoothing: the Methods state a Gaussian filter with a 1 h bandwidth, but the deposited code and published figures use 12 h, as identified from fig3.eps. 12 h is primary; 1, 3 and 6 h are reported. - Atmospheric-pressure correction: the paper uses hourly air pressure from the on-glacier station, which is embargoed. The code's constant offsets are primary, with JMA Syowa hourly pressure as a sensitivity case. - Tide: the deposit's tide file is in Syowa local time (UTC+3), and the authors shift it by 2.5 h. That shift is kept for the reproduction; the lag analysis uses UTC. - Data gaps are detected from timestamps instead of hard-coded row numbers. This gives identical segments. - Speed is differenced with the authors' schemes at 12 h (forward at GNSS2, centred at GNSS1) and centred at other bandwidths. - The paper does not define \"background speed\"; four baselines are declared instead. - Event windows come from the paper's text. The windows shaded in the authors' code are reported alongside. - Correlations for the grounded boreholes, which the authors show only as a scatter plot, are computed. - Rain frequency, air pressure and climate context use independent public records instead of the authors' extracts."""; ; """Reproduction (authors' data): - Input: the Mendeley deposit (doi:10.17632/8wvtxg53ry.1), downloaded and checked against the repository's published SHA-256 checksums, and analysed with new Python code. The authors' MATLAB scripts serve only as a reference for file formats, constants and conversions. - Pre-registration: a tolerance and decision rule for each sub-claim were committed in ANALYSIS_PLAN.md before analysis. Later changes are dated amendments, and every result is labelled pre-registered or post hoc. - Pressure: borehole pressures are converted to water level and to a fraction of flotation as in the authors' code; the paper's Eq. 1 is reported alongside. - GNSS: positions are projected to UTM zone 37S and smoothed with a Gaussian-kernel local linear regression. This reconstructs the authors' missing local_regression function, identified by matching the deposited fig3.eps. Horizontal speed is differenced from the smoothed positions. Data gaps are detected from the timestamps and optionally bridged with a not-a-knot cubic spline, as in the authors' supplementary figure. - Speed-up: computed against four declared background-speed baselines (local, campaign median, campaign trend, 7-day running median), at smoothing bandwidths of 1, 3, 6 and 12 h, and compared with speed fluctuations outside the events. - Tide: the authors' BH2203 correlation is repeated, then extended to the grounded boreholes with a 25 h high-pass filter and a lag scan. The clock of the tide file is checked against the IOC record of the same gauge. Replication (independent data, each test pre-registered before its data were downloaded): - Japan Meteorological Agency (JMA) Syowa daily weather summaries for rain frequency, 1990–2026, cross-checked against the same station's SYNOP reports in NOAA's Integrated Surface Database (WMO present-weather codes); - JMA hourly station pressure for the borehole correction; - JMA daily temperatures, and ERA5 2 m temperature from ECMWF's cloud-optimised archive, for the positive degree-day context; - passive-microwave melt flags (SSM/I 25 km, AMSR 10 km) and Sentinel-2 NDWI for surface melt; - an atmospheric-river catalogue (Favier 2025) for the January event; - ITS_LIVE image-pair velocities, to test whether the speed-up can be detected independently. The whole pipeline runs with pixi and Snakemake from a fresh checkout, and the GNSS processing is guarded by unit and regression tests."""; """The claim that surface meltwater reaching the bed accelerated grounded ice at Langhovde Glacier, East Antarctica, in summer 2021/22, tested through the observations it rests on: - basal water pressure relative to the flotation level, and its rise during the January 2022 rain and melt event; - the size of the speed-up at a grounded and a floating GNSS station during the December 2021 and January 2022 events; - uplift of the grounded station and its absence on floating ice; - the timing of the pressure and speed peaks; - the tidal connection between the bed and the sub-shelf cavity, and the head difference to a borehole below the grounding line; - the context that summer 2021/22 was unexceptional, with rare rain and no trend in temperature, positive degree-days or rain frequency. The causal mechanism is assessed only through these observations. Out of scope, because no data were deposited: freshwater at the bed (CTD), borehole video, drone imagery, sub-shelf fauna, and changes in ocean forcing or buttressing."""; . } sub:provenance { sub:assertion prov:wasAttributedTo . } sub:pubinfo { "Anne Fouilloux" . this: dc:created "2026-10-09T08:23:59.219Z"^^xsd:dateTime; dc:creator ; dc:license ; npx:introduces sub:langhovde-meltwater-acceleration-study; npx:wasCreatedAt ; "Reproduction and partial replication of Sugiyama et al. 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