MH370 Search Phase 1 Backscatter grids (GA-4421)

On behalf of Australia, and in support of the Malaysian accident investigation, the Australian Transport Safety Bureau (ATSB) was leading search operations for missing Malaysian airlines flight MH370 in the Southern Indian Ocean.

Geoscience Australia provided advice, expertise and support to the ATSB to facilitate bathymetric surveys, which were undertaken to provide a detailed map of the sea floor topography to aid navigation during the underwater search. Prior to the bathymetric survey, very little was known about the sea floor in the MH370 search area, as few marine surveys have taken place in the area. Existing maps of the sea floor were coarse, having been derived from satellites and only providing a general indication of water depth. Before the underwater search for MH370 could begin, it was necessary to accurately map the sea floor to ensure that the search is undertaken safely and effectively. Bathymetry survey vessels spent months at sea, scanning the sea floor with multibeam sonar to gather detailed, high-resolution data.

The multibeam backscatter data was acquired from Fugro Equator between June 2014 and February 2017 were processed by Geoscience Australia to 30 m resolution. This backscatter data was processed for the search area only, excluding all transit data and vessel turns. The data is presented as a yellow to bronze colour ramp, with high backscatter values in darker shades and overlain on a hillshade created from the 150 m bathymetry data. The hillshade was created with the parameters of point illumination azimuth at 45 degrees and altitude of 45 degrees.

应澳大利亚方面委托，并配合马来西亚事故调查工作，澳大利亚运输安全局（Australian Transport Safety Bureau，ATSB）牵头开展了南印度洋海域失联马来西亚航空公司MH370航班的搜寻作业。
澳大利亚地球科学局（Geoscience Australia）为ATSB提供咨询意见、专业技术支持与协助，以推进水深测绘作业——该作业旨在绘制高精度海底地形地图，为水下搜寻期间的航行提供辅助。此前MH370搜寻海域几乎未开展过海洋勘测，因此对该区域海底状况知之甚少。现有海底地图精度粗糙，仅基于卫星数据生成，仅能大致反映水深情况。在MH370水下搜寻启动前，必须精准绘制海底地图，以保障搜寻作业安全高效开展。搭载多波束声呐（multibeam sonar）的水深测量船在海上作业数月，对海底进行扫描以获取详细的高分辨率数据。
2014年6月至2017年2月期间从富格·赤道号（Fugro Equator）获取的多波束后向散射数据（multibeam backscatter data），经澳大利亚地球科学局处理至30米分辨率。本次数据处理仅针对搜寻海域范围，剔除了所有航行过渡数据与船舶转向数据。该数据以黄至古铜色的色阶呈现，后向散射值越高则色调越深，叠加于基于150米分辨率水深数据生成的晕渲图（hillshade）之上。该晕渲图采用方位角（azimuth）45度、高度角（altitude）45度的点照明参数生成。