Dated radar Internal Reflection Horizons (IRHs) from the Wilkes Subglacial Basin (East Antarctica) for ice-sheet model calibration (v2.0)

2025 Wilkes Subglacial Basin Isochrones (v2.0) This dataset is for all isochrones of age: 6.6 ± 0.1 ka, 13.1 ± 0.3 ka, 37.7 ± 0.5 ka, 64.1 ± 2.5 ka, 73.1 ± 1.2 ka, 90.8 ± 1.4 ka, 117.0 ± 1.3 ka, 122.8 ± 1.0 ka, and 128.4 ± 3.6 ka. Please note: an error in the use of the version of the AICC chronology was detected during the reviews of the paper. This led to the ages previously provided in the v1.0 dataset to change slightly. The updated (correct) ages are provided in this v.2.0. All files here have been updated to incorporate these changes. Field 1: Longitude (decimal degrees; WGS-84 EPSG: 4326)Field 2: Latitude (decimal degrees; WGS-84 EPSG: 4326)Field 3: Polar Stereographic X coordinates (metres; EPSG: 3031)Field 4: Polar Stereographic Y coordinates (metres; EPSG: 3031)Field 5: Pixel number of the corresponding isochrone relative to the BAS PASIN system range and sampling interval (value for conversion to metres: 3.8295)Field 6: Isochrone depth below the surface (set at 0) (metres; using firn corrections of 9.5 and 14.6 metres for IRHs dated at TALDICE and EDC respectively, and an electromagnetic wave speed in ice of 168.5e6 m/s)Field 7: Isochrone age (in years before present) dated either via intersections with existing stratigraphies (see below) or directly by intersection with the age-depth profile at TALDICE and EDC ice coresField 8: Ice thickness (in metres) calculated from the surface and bedrock returns from the along-track radar or gridded product, with no firn correction addedField 9: Surface elevation above sea level (in metres relative to the WGS-84 ellipsoid) from either the along-track radar dataset (usually using on-board LiDAR) or gridded product (relative to Field 14)Field 10: Bedrock elevation above sea level (in metres relative to the WGS-84 ellipsoid) from either the along-track bedrock pick from radar or gridded product (relative to Field 14)Field 11: Type of radar waveform (e.g., pulse or chirp) or name of institute who acquired the data onto which the corresponding isochrone was tracedField 12: Name of flightline onto which the corresponding isochrone was traced (relative to Field 11)Field 13: Name of ice core used to date the corresponding isochrone (either TALDICE or EDC), useful to determine the value for the firn correction used (relative to Field 6)Field 14: Integer indicating whether the ice thickness, surface, and bed elevation data are from (1) the along-track radar or (2) the gridded Bedmap3 product (Pritchard et al., 2025, Sci. Data) (relative to Field 8 and 10 respectively) Processing: Schlumberger Petrel (tracing) and MATLAB (data processing) Support: University of Bern Oeschger Centre for Climate Change Research, British Antarctic Survey, Alfred-Wegener Institute, The University of Texas at AustinFunding: Swiss National Science Foundation (SNSF) Starting Grant 2022 "Charting Antarctic Ice Sheet evolution via the ice sheet’s internal stratigraphy" (CHARIBDIS) Personnel: Julien A. Bodart ([e-mail])Personnel: Johannes C.R. Sutter ([e-mail]) Length_of_header: 52 linesNot_a_number: Missing values have been replaced by "NaN"Data separator: The separator is a single space Publication: Bodart et al., 2025 (in review; The Cryosphere; https://doi.org/10.5194/egusphere-2025-5381) Isochrones were traced primarily on the British Antarctic Survey's PASIN radar system flown during the WISE-ISODYN 2005-06 survey over the Wilkes Subglacial Basin and with a direct connection between the EDC and TALDICE ice core sites. Additional airborne radar datasets were also used to provide additional tiepoints and enhance crossover density in sparse areas. These additional datasets include individual flights from CRESIS Operation IceBridge using the MCoRDS radar system, AWI using the EMR radar system, and UTIG using the HiCARS radar system. The WISE-ISODYN data was acquired using the PASIN-1 radar system (centre frequency: 150 MHz; bandwidth: 20 MHz; sampling frequency: 22 MHz; sampling interval: 0.4545 ns), using a 0.1 μs pulse and a 4 μs, 10 MHz chirp simultaneously (abbreviated "_pL" and "_cL" respectively in the LINE_ID). Most of the radar data used in this study (except older AWI EMR data) were 2D SAR processed using advanced algorithms of different complexities. For more details on the radar processing methods used, please refer to Frémand et al. (2022, ESSD), CReSIS 2018 (manual), Nixdorf et al. (1999, An. Glac.), or Young et al. (2016, Phil. Trans. R. Soc. A). Further processing was also applied to the processed radar data to facilitate IRH tracing, including air-to-ice travel time removal (using LiDAR surface when available), surface alignment to 0, a custom gain function, and horizontal averaging to enhance englacial layering (Ashmore et al., 2020, GRL; Bodart et al., 2021, JGR-ES). These same steps were applied to all non-BAS radar datasets for consistency. All radar datasets were then exported to SEGY files with a "dt" scalar of 0.001. The BAS PASIN files were first imported into Schlumberger Petrel with a sampling interval of 1, reflecting the range of the radar system from top to bottom (range: approximately 1200 samples). All non-BAS data were then adapted in Petrel to match the vertical scale of the BAS PASIN vertical axis so as to facilitate tracing and avoid vertical offsets between datasets. The isochrones were dated using the AICC2023 chronology (Bouchet et al., 2023, CP) at intersections with TALDICE and EDC cores, or via intersection with published stratigraphies (Winter et al., 2019, TC; Cavitte et al., 2021, ESSD). Only isochrones traced as part of this project are included to avoid duplication with previously published work. An extra column in the dataset indicates where each data point was dated (either TALDICE or EDC). The ice thickness, surface, and bed elevations values provided in this dataset come directly from the along-track radar, where possible. Where there are no data for the ice thickness, surface, or bed elevations, the values come from the gridded Bedmap3 data product (see Field 14 for source of elevation values).2025年威尔克斯冰下盆地等时线（v2.0版） 本数据集包含以下所有年龄的等时线（Isochrones）：6.6±0.1 ka、13.1±0.3 ka、37.7±0.5 ka、64.1±2.5 ka、73.1±1.2 ka、90.8±1.4 ka、117.0±1.3 ka、122.8±1.0 ka及128.4±3.6 ka。 请注意：在论文审稿过程中，我们发现了AICC年表（AICC chronology）版本使用错误，导致v1.0版数据集此前提供的年龄数据发生小幅修正。本v2.0版已采用更新后的（正确）年龄数据，所有文件均已同步更新以纳入上述修正。 字段1：经度（十进制度；WGS-84大地坐标系，EPSG:4326） 字段2：纬度（十进制度；WGS-84大地坐标系，EPSG:4326） 字段3：南极极射赤平投影X坐标（米；EPSG:3031） 字段4：南极极射赤平投影Y坐标（米；EPSG:3031） 字段5：对应等时线的像素编号，基于英国南极调查局（BAS）PASIN系统的探测范围与采样间隔（转换为米的系数：3.8295） 字段6：等时线埋深（米；以地表为基准，即埋深0米。其中TALDICE与EDC冰芯定年的冰内反射层分别采用9.5米和14.6米的粒雪层校正，冰中电磁波传播速度为168.5×10^6 m/s） 字段7：等时线年龄（距今年数），定年方式包括与已有地层序列相交，或直接与TALDICE、EDC冰芯的年龄-深度剖面相交 字段8：冰厚（米），由沿轨雷达或网格化产品的冰面与基岩回波计算得到，未施加粒雪层校正 字段9：冰面海拔高程（米，基于WGS-84椭球体），数据来源为沿轨雷达数据集（通常采用机载激光雷达数据）或网格化产品（详见字段14） 字段10：基岩海拔高程（米，基于WGS-84椭球体），数据来源为沿轨雷达基岩拾取结果或网格化产品（详见字段14） 字段11：雷达波形类型（如脉冲或线性调频脉冲），或描迹对应等时线所用数据的获取机构名称 字段12：对应等时线所在的飞行航线名称（关联字段11） 字段13：用于定年对应等时线的冰芯名称（TALDICE或EDC），用于确定所用粒雪层校正系数（关联字段6） 字段14：整数型标识，用于说明冰厚、冰面与基岩高程数据的来源：(1) 沿轨雷达数据；(2) 网格化Bedmap3数据集（Pritchard等，2025，《科学数据》）。分别关联字段8与字段10 处理软件：Schlumberger Petrel（用于等时线描迹）与MATLAB（用于数据处理） 支持单位：伯尔尼大学厄施格气候变化研究中心、英国南极调查局、阿尔弗雷德·魏格纳研究所、德克萨斯大学奥斯汀分校 资助方：瑞士国家科学基金会（SNSF）2022年启动基金“通过冰盖内部地层结构绘制南极冰盖演化图谱”（CHARIBDIS项目） 项目人员：朱利安·A·博达尔（Julien A. Bodart，邮箱：[e-mail]）；约翰内斯·C·R·萨特（Johannes C.R. Sutter，邮箱：[e-mail]） 表头行数：52行 非数值项：缺失值已替换为“NaN” 数据分隔符：采用单个空格作为分隔符 发表信息：博达尔等（Bodart et al.），2025年（已投稿待审，《冰冻圈（The Cryosphere）》；DOI：10.5194/egusphere-2025-5381） 本数据集的等时线主要通过英国南极调查局的PASIN雷达系统获取，该系统搭载于WISE-ISODYN 2005-2006年在威尔克斯冰下盆地开展的科考飞行中，且直接关联EDC与TALDICE冰芯站点。此外，本研究还使用了额外的机载雷达数据集，以在数据稀疏区域补充控制点并提升交叉点密度。这些额外数据集包括：CRESIS“冰桥行动”（Operation IceBridge）搭载MCoRDS雷达系统的飞行数据、阿尔弗雷德·魏格纳研究所（AWI）搭载EMR雷达系统的飞行数据，以及德克萨斯大学奥斯汀分校（UTIG）搭载HiCARS雷达系统的飞行数据。 WISE-ISODYN项目的数据采用PASIN-1雷达系统获取，其参数为：中心频率150 MHz、带宽20 MHz、采样频率22 MHz、采样间隔0.4545 ns，同时搭载0.1 μs脉冲与4 μs、10 MHz线性调频脉冲（在LINE_ID中分别简写为“_pL”与“_cL”）。本研究使用的大部分雷达数据（除老旧的AWI EMR数据外）均采用不同复杂度的高级算法进行了二维合成孔径雷达（SAR，Synthetic Aperture Radar）处理。如需了解所用雷达处理方法的更多细节，请参考Frémand等（2022，《地球系统科学数据（ESSD）》）、CReSIS 2018（手册）、Nixdorf等（1999，《冰川学年鉴（An. Glac.）》）以及Young等（2016，《英国皇家学会哲学学报A辑（Phil. Trans. R. Soc. A）》）。为便于冰内反射层描迹，研究人员还对已处理的雷达数据进行了额外处理，包括去除冰面飞行时间（有机载激光雷达数据时采用对应表面数据）、将表面高程对齐至0、自定义增益函数，以及水平平均以强化冰内层理（Ashmore等，2020，《地球物理研究快报（GRL）》；Bodart等，2021，《地球物理学研究杂志：地球表面（JGR-ES）》）。为保证一致性，所有非英国南极调查局的雷达数据集均采用了相同的处理步骤。 所有雷达数据集最终均导出为dt标量为0.001的SEGY格式文件。英国南极调查局的PASIN数据文件首先以采样间隔1导入Schlumberger Petrel软件，该采样间隔对应雷达系统的全程探测范围（约1200个采样点）。随后，所有非英国南极调查局的数据均在Petrel中进行适配，以匹配英国南极调查局PASIN数据的垂直比例尺，从而便于描迹并避免数据集间的垂直偏移。 等时线的年龄通过两种方式确定：一是在与TALDICE和EDC冰芯的交点处采用AICC2023年表（Bouchet等，2023，CP）进行定年；二是通过与已发表的地层序列（Winter等，2019，TC；Cavitte等，2021，《地球系统科学数据（ESSD）》）相交进行定年。 本数据集仅包含本项目中描迹得到的等时线，以避免与已发表的研究成果重复。数据集新增一列，用于标注每个数据点的定年基准（TALDICE或EDC）。 本数据集提供的冰厚、冰面高程与基岩高程数据，在可行情况下直接来自沿轨雷达观测数据。若沿轨雷达未提供冰厚、冰面或基岩高程数据，则采用网格化的Bedmap3数据集的对应值（高程数据来源详见字段14）。