The eastern Gulf of Mexico (GOM) is a region of complex ocean circulation dynamics, with an energetic western boundary current, the GOM Loop Current, and its related eddies located in deep water, both interacting along the shelf slope with the wide, gently sloping West Florida Shelf (WFS). As an oceanographic process and data rich region, the eastern GOM is well suited for veracity testing and applications of altimetry products.
We propose to evaluate several altimetry products in oceanographic context with applications in the eastern GOM for the purposes of:
- determining the accuracy of the altimetry data products alone, relative to their use in numerical circulation models for providing essential information on ocean surface currents of use in offshore oil and gas operations, hazardous spill mitigation, SAR and water property transport, both in deep water and onto the continental shelf; and
- determining the shoreward extent for which altimeter-estimated currents may be applied on the WFS and over what time scales of variability.
A Lagrangian particle trajectory model based on the altimetry-derived surface currents will be used to hindcast the surface drifter trajectories observed in the eastern GOM during summer 2010. The performance of the altimetry based trajectory model will also be compared with calculations from numerical circulation models used in response to the Deepwater Horizon oil spill. Both altimetry-derived and numerical model estimated velocity will be compared with an unprecedented set of in situ velocity observations (data from moored ADCPs) and velocity from remotely sensing HF-radars (using two different types of radars, CODAR and WERA) on the WFS available to us. This veracity testing exercize with specific applications is an essential first step toward future applications of coastal altimetry data.
With coastal oceanography being an emerging area of emphasis in NASA's Physical Oceanography program, it is important to define the limits of application of altimetry data when transitioning from deep ocean areas to the continental shelf where other satellite products such as SST and ocean color are already of great use in advancing knowledge on societal relevant processes such as red tide. Demonstrating both the utility and limitations of satellite altimetry products in transition from the deep ocean to the continental shelf where society meets the sea is the essence of our proposal. It is also important that experimental physical oceanographers and satellite altimetry experts work together to validate and exploit altimetry products. Not only because the local oceanographers have an archive of valuable in situ observations, the expertise through the long-term dedicated efforts in regional oceanography of the study area is essential to correctly interpret data analysis results and, consequently, to improve altimetry products.