ABSTRACT

Modeling and predicting ocean currents are great challenges for physical oceanography due to the lack of direct measurements. Mobile sensor networks have been proven to be an effective tool to answer this challenge, providing estimated flow information along the Lagrangian trajectories. To incorporate these flow estimates into ocean models, existing approaches based on Lagrangian data assimilation usually require significant amount of computing power.  We develop generic environmental models (GEMs) to combine computational ocean models with real-time data streams collected by mobile sensing platforms to provide high-resolution predictions of ocean current in a small spatial area around the mobile platforms.  Motion tomography (MT) can be viewed as a novel way to construct GEMs. The method fuses the data collected by multiple mobile platforms along their paths to formulate an “inverse problem” that has been the core problem underlying medical CT imaging. By solving this inverse problem, a high-resolution spatial map of ocean flow in the volume traversed by the mobile platforms can be reconstructed. While a similar inverse problem has been formulated and solved in ocean acoustic tomography to reconstruct spatial maps of sound speed, motion tomography provides a “directly measured” Eulerian map of ocean current, which has never been achieved by other means before. MT may significantly increase the spatial accuracy of GEMs. More accurate GEMs also feed high quality data to data assimilation algorithms, hence eventually improve ocean circulation models.

SHORT BIO

Dr. Fumin Zhang is Associate Professor in the School of Electrical and Computer Engineering at the Georgia Institute of Technology. He received a PhD degree in 2004 from the University of Maryland (College Park) in Electrical Engineering, and held a postdoctoral position in Princeton University from 2004 to 2007. His research interests include mobile sensor networks, maritime robotics, control systems, and theoretical foundations for cyber-physical systems. He received the NSF CAREER Award in September 2009, the Lockheed Inspirational Young Faculty Award in March 2010, the ONR Young Investigator Program Award in April 2010, and the GT Roger P. Webb Outstanding Junior Faculty Award in April 2011. He is currently serving as the co-chair for the IEEE RAS Technical Committee on Marine Robotics, and the chair for the IEEE CSS Technical Committee on Robotic Control and Manufacturing Automation.