CLIMATOLOGICAL STUDY OF THE TOTAL OZONE FIELD AROUND THE SUBTROPICAL JET-STREAM

A study of the average distribution of total ozone was accomplished fo r the period from October 1982 to September 1983 in the area 20-50-deg rees-N, 90-160-degrees-E, i.e. the entrance region of the East Asian s ubtropical jet stream. Total ozone data were obtained from the Total O zone Mapping Spectrometer on the Nimbus-7 satellite. Normally, the sub tropical jet stream (STJ) marks a steep gradient in total ozone. From the monthly mean study of total ozone and wind fields at the 200 hPa s urface, it was found that in winter the total ozone contours are almos t parallel to the wind directions; the horizontal gradient in total oz one increases as the wind speed strengthens. In winter and spring, a s harp gradient in total ozone is found on the cyclonic side of the STJ because of the strong Hadley circulation. As the Hadley cell ceases in summer, the jet weakens and horizontal gradients in total ozone becom e much smaller, disappearing almost entirely by early autumn.