Evaluation of the NAVD 88 Using Aerogravity and Lidar Data in the Gulf of Mexico

OVERVIEW

•Existing vertical datum for U.S., NAVD 88, has meter-level bias and trend problems

–Altimeter profiles across Great Lakes

–Comparisons to GRACE-based EGM’s

•Use GRACE-based EGM’s enhanced by local gravity for datum definition

•Need to ensure the gravity data are consistent and seamless

–From offshore to onshore (shipborne vs. terrestrial groups)

–Fill in gapped regions and edge regions

•Gravimetric Geoid + MDT = Observed Mean Sea Surface

–Need open-ocean lidar observations for MDT

–Can validate this approach at coastal stations (TBM’s)

•Benefits: more accurate coastal heights, improved emergency and coastal management, validation of satellite missions (on a larger scale)