Long-term trends of winter monsoon synoptic circulations over the maritime continent: 1962-2007

The present study examines the long-term trends of the winter monsoon northeasterly cold surge and Borneo vortex over the South China Sea. There has been a significant increase in the frequency of the Borneo vortex within the study period of 1962-2007. The location of the center of the Borneo vortices has shifted slightly offshore; northward of western Borneo. This could result in less vortex-land interaction and lengthen the life span of the vortices due to less frictional shear and hence increase the vortex days. These changes could be related to the strengthened easterly component of the cold surge winds. Copyright (C) 2010 Royal Meteorological Society