Canada, the USA, and Mexico are collaborating to develop a unified gravimetric geoid model which will serve as the vertical reference surface for North America, designated as GEOID2022. It represents a new realization of the Canadian Geodetic Vertical Datum of 2013 (CGVD 2013). To achieve this, responsible agencies from each country are compiling a shared dataset comprising gravity observations, a digital elevation model (DEM), and a reference global gravity model (GGM). In this contribution, we provide details of this shared dataset, e.g., data preparation, cleaning, and compilation. Furthermore, we present how the new dataset differs from what was used in the computation of the previously adopted geoid model in Canada, namely the Canadian Gravimetric Geoid Model of 2013 version a (CGG2013a).
In particular, we provide details of the following:
-Gravity observations: Collected via terrestrial, marine, and airborne gravity surveys, sourced from institutions including the Canadian Geodetic Survey (CGS), National Geodetic Survey (NGS), National Geospatial-Intelligence Agency (NGA), National Institute of Statistics and Geography (INEGI), and Technical University of Denmark (DTU).
-DEM: called XGEOID20 and provided through the compilation of various DEMs, such as TanDEM-X, USGS 3DEP 1” DEM, and MERIT.
-GGM: called xGeoidRefB and prepared by compilation of EGM2008 with GOCO06S, and GRAV_D airborne gravity observations with an epoch of 2020.
CGS has been using the Stokes-Helmert technique for the determination of the Canadian geoid models, a practice continuing with GEOID2022. We will also provide insights into the present status of the geoid model computed by CGS.