Update VDatum for the coastal waters of Texas and western Louisiana : modeled tidal datums and their associated spatially varying uncertainties

NOAA NOS has been conducting a continuous development for a seamless nationwide vertical datum transformation system (a software tool “VDatum”) for an effective transformation of geospatial data among a variety of three-dimensional ellipsoidal, orthometric, and tidal datum reference systems. The current modeling work was aimed at updating modeled tidal datums in the Texas and western Louisiana coastal regions in support of the development of the NOAA VDatum tool. An initial development of tide model in this model domain was made in 2013 for tidal datum calculations. The initial work is important for understanding basic characteristics of tidal datums in the coastal regions. This work was focused on: (1) updating the tide model by using the most currently available shoreline, bathymetry, and tide station data; (2) implementing a Spatially Varying Uncertainty (SVU) statistical interpolation method (Shi and Myers, 2016) for correcting modeled tidal datums and computing associated uncertainties; and (3) using modeled tidal datums to upgrade coastal non-tidal polygons for improving the quality of tidal datum marine grid population.