Terms of Reference and Objectives
The primary objective of the Project is the development of a regional gravity field and geoid model for North America in order to achieve a common vertical datum. “North America" will encompass Iceland, Greenland, Canada, the U.S.A. (including Alaska and Hawaii), and Mexico as well as countries forming Central America, the Caribbean Sea, and the northern portions of South America.
Both Canada and the U.S.A. are moving towards the definition of new vertical datums based on gravimetric geoids, and other countries may adopt similar approaches if a suitable model is developed that meets their respective national interests. The intent here is to ensure a suitable North American Geoid is developed to serve as a common datum for everyone as well as the basis for a forthcoming International Great Lakes Datum model in 2015 (IGLD 15). Likewise, all countries in the region would be served by having access to a common model for translating oceanographic effects to terrestrial datums for various scientific, commercial, engineering, a disaster preparedness applications.
The achievement of a geoid model for North America will be accomplished by coordinating activities between agencies and universities with interest in geoid theory, gravity, gravity collection, gravity field change, geophysical modeling, digital elevation models (DEM), digital density model (DDM), altimetry, dynamic ocean topography, leveling and vertical datums. Of particular interest will be relating geoid and ocean topography models to ocean topography and tidal bench marks.
The determination of a geoid model for North America is not limited to a single agency, which will collect all necessary data from all countries. The Project encourages theoretical diversity in the determination of a geoid model between the agencies. Each agency takes responsibility or works in collaboration with neighboring countries in the development of a geoid model for their respective country with an overlap (as large as possible) over adjacent countries. Each solution will be compared, the discrepancies will be analyzed, and the conclusions will be used to improve on the next model.
Program of Activities
The Project will support geoid activities in countries where geoid expertise is limited by encouraging more advanced members to contribute their own expertise and software. The Project will encourage training and education initiative of its members (e.g., International Geoid Service (IGeS geoid school and graduate studies).
The chair of the Project will meet with the equivalent European and South American projects to discuss overlap regions and to work towards agreements to exchange data. Finally, the members of the Project will keep close contact with all related Study Groups of the IAG. The Project is open to all geodetic agencies and universities across North America with an interest in the development of a geoid model for North America. The meetings of the Commission Project 2.2 are open to everyone with interests in geodesy, geophysics, oceanography and other related topics.
Members will communicate primarily using emails. However, members of the Project plan to arrange annual meetings. Preferably, these meetings will be held during international conferences where most members will be present; however, some meetings will be held in North America to minimize travel costs. Minutes of meeting will be prepared and sent to all members of the Project.