Anomalous Upwelling in Nan Wan: July 2008

Tidally induced, sudden temperature drops in Nan Wan, particularly pronounced during the spring tide, often bear ecological consequences. We use an Ocean Nowcast/Forecast System (ONFS) at the US Naval Research Laboratory (NRL) to examine a Widely publicized cold-water intrusion event in July 2008, and compare it with what we perceived as a normal intrusion event ill June 2007. For a normal cold-water intrusion, cold anomalies eventually propagate away in forms similar to internal Kelvin waves. For early July Of 2008, the NRL ONFS suggested all anomalous, subtidal and essentially eastward current near Nan Wan. The subtidal Current, Superimposed on the ebb Current, blocks the propagation of cold anomalies ill the direction of internal Kelvin waves, inducing anomalous and inefficient cold-water dispersal. The NRL ONFS also Suggested the anomalous subtidal current as a post-typhoon response to the passage of Typhoon Fengshen.