The U.S. Navy’s Real Time Altimetry Data Processing in Ocean Monitoring and Forecasting
Kirk Whitmer(1) , Gregg Jacobs(1) , Ole Martin Smedstad(2) , and Charlie Barron(1)
Naval Research Laboratory,
Stennis Space Center, MS 39529,
(2) Planning Systems Incorporated, NRL 7320, Stennis Space Center, MS 39529, United States
The U.S. Navy has a long history with satellite altimetry going back to virtually its nascence. Over this time it has incorporated data from almost every mission: GEOSAT, ERS-1/2, TOPEX/Poseidon, GFO, Jason-1, and Envisat. The data produced has been invaluable to the understanding of the ocean environment, both through its direct measurements and assimilation into other systems. Due to the Navy’s operational nature, the largest emphasis has been on real time and forecasting applications. The benefits to the Navy and commercial interests has been multifold and ever expanding as new applications and technologies are discovered. Two staple Navy altimeter data assimilating systems, the Navy Layered Ocean Model (NLOM) and Modular Ocean Data Assimilation System (MODAS), are presented in the light of their ability to accurately monitor and forecast the ocean environment. These systems and many others have benefited or been made possible by the advent of high precision altimeters like TOPEX/Poseidon and Jason-1. The improvements in processing techniques, sea state bias determination, and environmental corrections, along with improved tide models and more precise orbits have all combined to aid in the greatest understanding of the global ocean ever. An overview of the processing techniques utilized by the Navy in creating real time altimeter products is presented. Special focus is given to techniques unique to the Navy’s processing. These include the mean sea surface employed in determining sea surface height anomalies and an orbit correction technique. Refinements and development of improved altimetry data processing techniques continue as altimetry remains the backbone of numerous Navy systems.