Gridded segments of sea-ice or snow surface elevation and freeboard from helicopter-borne laser scanner during the MOSAiC expedition flight 20200921_01, version 1

This data set is a higher-processing-level version of Geolocated sea-ice or snow surface elevation point clouds from helicopter-borne laser scanner during the MOSAiC expedition, version 1 (Jutila et al., 2022; doi:10.1594/PANGAEA.950509), where the surface elevation point cloud has been converted to freeboard using automatic open water detection scheme and projected onto a regular 0.5-meter grid. The data were collected using a near-infrared, line-scanning Riegl VQ-580 airborne laser scanner (hdl:10013/sensor.7ebb63c3-dc3b-4f0f-9ca5-f1c6e5462a31 & hdl:10013/sensor.7a931b33-72ca-46d0-b623-156836ac9550) mounted in a helicopter along the MOSAiC drift from the north of the Laptev Sea, across the central Arctic Ocean, and towards the Fram Strait from September 2019 to October 2020. The flights are both small scale, ~5x5 km grid patterns mainly over the central observatory, and large scale, few tens of km away from RV Polarstern, triangle patterns, or transects. The gridded data are stored in 30-second along-track segments in netCDF format. For the small scale grid flights, the data are drift corrected using the position and heading data of RV Polarstern and elevation offset corrected using overlapping segments to overcome degraded GPS altitude data >85°N. Open water points are identified to derive a freeboard estimate from the surface elevations. For the flights with degraded GPS altitude quality, we provide only a freeboard estimate (grid pattern flights) or no freeboard (transects). The gridded 30-s segments include as data variables: surface elevation, freeboard (estimate), freeboard uncertainty, estimated sea surface height, surface reflectance, echo width, and number of points used in the interpolation. In addition, list of detected open water points and an overview figure of each flight is provided.本数据集为MOSAiC科考期间直升机搭载激光扫描仪获取的地理定位海冰/雪面高程点云的高阶处理版本（版本1，Jutila等人，2022；doi:10.1594/PANGAEA.950509）。 该数据集通过自动开阔水域识别算法将原始表面高程点云转换为海冰干舷（freeboard），并投影至规则0.5米网格。 数据采集采用搭载于直升机的近红外线扫描Riegl VQ-580机载激光扫描仪（Handle系统永久标识符：hdl:10013/sensor.7ebb63c3-dc3b-4f0f-9ca5-f1c6e5462a31 与 hdl:10013/sensor.7a931b33-72ca-46d0-b623-156836ac9550），采集范围覆盖从拉普捷夫海北部途经北冰洋中部，直至弗拉姆海峡的MOSAiC科考漂移航线，时间为2019年9月至2020年10月。 飞行作业分为两种尺度：小尺度作业以约5×5公里的网格模式为主，覆盖中部观测站区域；大尺度作业则在距极星号（RV Polarstern）科考船数十公里范围内开展，采用三角网格模式或断面航线模式。 网格化数据以沿轨30秒片段的形式存储为netCDF格式。针对小尺度网格飞行作业，数据集采用极星号科考船的位置与航向数据进行漂移校正，并通过重叠片段进行高程偏移校正，以解决北纬85°以上区域GPS高程数据精度退化的问题。 通过识别开阔水域点，从表面高程数据中推导得到海冰干舷估算值。对于GPS高程数据质量退化的飞行作业，仅提供网格模式飞行的干舷估算值，断面航线作业则不提供干舷数据。 网格化30秒片段包含以下数据变量：表面高程、干舷（估算值）、干舷不确定性、估算海表高度、表面反射率、回波宽度以及插值所用的点数。此外，数据集还附带检测到的开阔水域点列表以及各次飞行作业的概览图。

搜集汇总

背景与挑战

背景概述

该数据集是MOSAiC考察期间直升机载激光扫描仪获取的海冰或雪表面高程和自由板的网格化数据，经过高级处理，将点云转换为自由板并投影到0.5米网格上。数据收集于2019年9月至2020年10月，覆盖北极地区，以30秒沿航迹段存储为netCDF格式，包括表面高程、自由板估计和不确定性等关键变量，用于研究海冰变化。