Abstract:
Storm track is a region where in the synoptic eddy activity is statistically most prevalent and intense. At daily weather charts, it roughly corresponds to the mean trajectories of cyclones or anticyclones. In this paper, the recent 0.5°×0.5° horizontal resolution QuikSCAT (QuikBird Satellite Microwave Scatterometer Sea Winds Data) wind data, NCEP (National Center for Environmental Prediction) 10 m-height wind data and the global reanalysis data at various pressure-levels are employed to document the spatial structure of storm track over the North Pacific in the winter (January) and summer (July) from 1999 to 2005. It is found that in winter the intensity of storm track over the North Pacific is stronger and its position is located in lower-latitude with showing distinct zonal shaped distribution. While in summer, the intensity of storm track over the North Pacific is weaker and its position is located in higher-latitude. Based upon the characteristics of horizontal distributions of geopotential height variance at various pressurelevels, threedimensional schematic diagrams of storm track in winter and summer are plotted, respectively. Further analyses of high-resolution QuikSCAT wind data indicate that this data can depict the storm track in detail. Not only some previous results on double storm tracks over the Southern Oceans detected by Nakamura are confirmed, but also some new discoveries about double storm tracks over the North Pacific and the North Atlantic, named as subtropical storm track and subpolar storm track respectively, are found. The statistical analyses of cyclone tracks and anticyclone tracks in the winters from 1999 to 2005 over the North Pacific provided a solid evidence for the existence of double storm tracks over the North Pacific.