Abstract We present a novel study to utilize US Geological Survey water level gauges that were not meant for tidal studies to diagnose errors in the National Oceanic and Atmospheric Administration (NOAA) Vdatum tool in southeastern Louisiana and western coastal Mississippi. The US NOAA developed a Vertical Datum Transformation tool (VDatum) that allows for conversions between geodetic, orthometric, and tidal vertical datums. However, in southeastern Louisiana and western Mississippi, VDatum uncertainties have been reported by NOAA to be perhaps as high as 0.20–0.50 m (https://vdatum.noaa.gov/). These uncertainties exceed IHO S44 special order and order 1. We performed validation measurements for VDatum in the region of concern at three USGS water level gages (CSX Railroad, Delacroix, and Rigolets) and one offshore location (Chandeleur East) utilizing a HydroLevel buoy. Tidal datums estimated using Modified Range Ratio method at these stations were compared with the corresponding tidal datums determined using VDatum. We hypothesize that the errors in VDatum are due to errors in: the tuning of the model or in the model bathymetry and coastline resulting in an incorrect tidal range, and in the topography of the sea surface in that region.

中文翻译：

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路易斯安那州东南部和密西西比州西部沿海地区 VDatum 的验证

摘要 我们提出了一项新颖的研究，利用美国地质调查局水位计来诊断路易斯安那州东南部和密西西比州西部沿海国家海洋和大气管理局 (NOAA) Vdatum 工具中的错误，该水位计不适用于潮汐研究。美国 NOAA 开发了一种垂直基准转换工具 (VDatum)，允许在大地测量、正角和潮汐垂直基准之间进行转换。然而，在路易斯安那州东南部和密西西比州西部，NOAA 报告的 VDatum 不确定性可能高达 0.20-0.50 m (https://vdatum.noaa.gov/)。这些不确定性超过了 IHO S44 特殊订单和订单 1。我们在三个 USGS 水位计（CSX Railroad、Delacroix、和 Rigolets）和一个使用 HydroLevel 浮标的海上位置（Chandeleur East）。在这些台站使用修正极差比方法估计的潮汐基准与使用 VDatum 确定的相应潮汐基准进行了比较。我们假设 VDatum 中的错误是由于以下方面的错误造成的：模型的调整或模型的测深和海岸线导致潮汐范围不正确，以及该地区海面的地形。