NOAA / NGA Satellite Computed Bathymetry Assessment-SCuBA

One of the National Geospatial-Intelligence Agency’s (NGA) and the National Oceanic and Atmospheric Administration’s (NOAA) missions is to ensure the safety of navigation on the seas by maintaining the most current information and the highest quality services for U.S. and global transport networks. To achieve this mission, we need accurate coastal bathymetry over diverse environmental conditions. The SCuBA program focused on providing critical information to improve existing bathymetry resources and techniques with two specific objectives. The first objective was to validate National Aeronautics and Space Administration’s (NASA) Ice, Cloud and land Elevation SATellite-2 (ICESat-2), an Earth observing, space-based light detection and ranging (LiDAR) capability, as a useful bathymetry tool for nearshore bathymetry information in differing environmental conditions. Upon validating the ICESat-2 bathymetry retrievals relative to sea floor type, water clarity, and water surface dynamics, the next objective is to use ICESat-2 as a calibration tool to improve existing Satellite Derived Bathymetry (SDB) coastal bathymetry products with poor coastal depth information but superior spatial coverage. Current resources that monitor coastal bathymetry can have large vertical depth errors (up to 50 percent) in the nearshore region; however, derived results from ICESat-2 shows promising results for improving the accuracy of the bathymetry information in the nearshore region. <br/> <br/> <strong>Project Overview</strong> <br/> One of NGA’s and NOAA’s primary missions is to provide safety of navigation information. However, coastal depth information is still lacking in some regions—specifically, remote regions. In fact, it has been reported that 80 percent of the entire seafloor has not been mapped. Traditionally, airborne LiDARs and survey boats are used to map the seafloor, but in remote areas, we have to rely on satellite capabilities, which currently lack the vertical accuracy desired to support safety of navigation in shallow water. In 2018, NASA launched a space-based LiDAR system called ICESat-2 that has global coverage and a polar orbit originally designed to monitor the ice elevation in polar regions. Remarkably, because it has a green laser beam, ICESat-2 also happens to collect bathymetry information <a href="nasa.gov">ICESat-2</a>. With algorithm development provided by University of Texas (UT) Austin, NGA Research and Development (R&amp;D) leveraged the ICESat-2 platform to generate SCuBA, an automated depth retrieval algorithm for accurate, global, refraction-corrected underwater depths from 0 m to 30 m, detailed in Figure 1 of the documentation. The key benefit of this product is the vertical depth accuracy of depth retrievals, which is ideal for a calibration tool. NGA and NOAA National Geodetic Survey (NGS), partnered to make this product available to the public for all US territories. <a href="https://raw.githubusercontent.com/NOAA-Big-Data-Program/bdp-data-docs/main/SCuBA/SCuBA_Infographic_small.png">View the SCuBA Info Graphic</a> <br/> All details on how SCuBA was developed, how to access data, and how to use the data, please visit the <a href="https://github.com/NOAA-Big-Data-Program/bdp-data-docs/blob/main/SCuBA/NOAA_website_SCUBA_22MAY24_GOLD.docx.pdf">DOCUMENTATION</a> page.

国家地理空间情报局（NGA）及国家海洋和大气管理局（NOAA）的使命之一，便是确保海上航行的安全。为此，他们致力于维护最及时的信息和最高品质的服务，以满足美国及全球交通网络的需求。为实现此使命，我们需要在不同环境条件下获取精确的海岸地形信息。SCuBA项目专注于提供关键信息，以改进现有的海岸地形资源和技术，并设定了两个具体目标。首先，验证美国国家航空航天局（NASA）的冰、云和陆地高程卫星-2（ICESat-2）——一种基于空间的光探测与测距（LiDAR）地球观测能力——作为不同环境条件下近岸地形信息的有用工具。在验证ICESat-2相对于海底类型、水透明度和水面动力学方面的地形提取后，接下来的目标是利用ICESat-2作为校准工具，以提高现有基于卫星的海岸地形产品（SDB）的精度，尽管这些产品在海岸深度信息上存在不足，但具有优越的空间覆盖能力。目前监测海岸地形资源可能存在较大的垂直深度误差（高达50%），然而，从ICESat-2得出的结果显示出改善近岸地区地形信息精度的巨大潜力。