P-9

Assessment of a now-casting system for flow-tracking of Lake Biwa

G. Auger (Ritsumeikan University), Y. Aota (Ritsumeikan University), J.C. Wells (Ritsumeikan University)

On several occasions large amount of turbid water into Lake Biwa from surrounding waters has been observed, especially during typhoon seasons. It also has been reported that garbage was advected during such events. For disaster mitigation purposes, we are developing a now-casting system to track the flow field of Lake Biwa in real time, including a state-of-the-art data assimilation scheme.

In this poster we present results of the assessment of performances from the Observation System Simulation Experiment analysis of the first now-casting system of lakes and coastal areas in Japan. We implemented the Local Ensemble Transform Kalman Filter scheme to assimilate temperature and surface elevation data streams, located at the same locations than existing moorings to be consistent with in-field use. In our OSSE, the "truth" simulation models the period August and September 1993, a period with three typhoons that passed over Lake Biwa. In our now-casting system, we perform the ensemble "now-casts" using the breeding method.