南极罗斯海高分辨率数字水深模型

A NEW HIGH-RESOLUTION DIGITAL BATHYMETRIC MODEL OF THE ROSS SEA, ANTARCTICA

数字水深模型是描绘海底地形地貌的水深地形图,在罗斯海陆架上,冰盖的进退形成形态大小各异的海底冰川地貌,而对海底冰川地貌的解释研究需要高分辨率数字水深模型的支持。采用36个国际公开航次采集到的多波束水深数据以及GEBCO_2014网格水深数据,融合、编绘成50 m网格间距的高分辨率罗斯海数字水深模型。由于采用的多波束水深数据来源于不同调查船只、不同多波束声呐系统及不同航次,这给多波束水深数据的精度评估、融合等带来一定的困难。本文首先采用通用绘图工具(GMT)对多波束中央波束水深数据的交点误差做统计分析,再利用统计分析结果对不同航次水深数据做出精度评估,最后利用"移除-恢复"法对两种来源及精度不同的水深数据做最后的融合。通过以上步骤得到的罗斯海高分辨率数字水深模型与国际南大洋水深地形图(IBCSO)相比,能够更加清晰地凸显海底微地形地貌特征,尤其是冰川进退过程中产生的地貌特征,可满足罗斯海海底冰川地貌的解释工作及综合地质地球物理研究任务。

A digital bathymetric model is a topographic map showing the underwater depth of the seafloor. On the Ross Sea shelf, ice sheet advance and retreat create submarine glacial landforms of different shapes and sizes. Interpretation of these landforms requires the support of a high-resolution digital bathymetric model. A high-resolution digital bathymetric model of the Ross Sea with 50-meter grid spacing was created from multi-beam bathymetric data acquired on 36 international sea voyages and the GEBCO2014 grid bathymetric data. The multi-beam bathymetric data came from different survey vessels, echo-soundings, and voyages, which makes data fusion and accuracy assessment difficult. Generic Mapping Tools were used to calculate nadir-beam crossover-error statistics to assess data accuracy. Fusion of data from two sources and with different accuracies was conducted using the remove-restore method. Compared with the International Bathymetric Chart of the Southern Ocean, our high-resolution digital bathymetric model can highlight submarine micro-topographic features more clearly, especially the geomorphological features created during glacier advance and retreat. Therefore, our model can be used to support the interpretation of submarine glacial landforms and the comprehensive geophysical research tasks that are taking place in the Ross Sea.