Meteorological College
Aerological Observatory
Meteorological Research Institute
Observations Department, Japan Meteorological Agency
Meteorological Research Institute
Observations Department, Japan Meteorological Agency
Observations Department, Japan Meteorological Agency
Atmospheric Environment Service
抄録(英)
Monthly average total ozone and monthly average temperature at 50hPa (T_<50>) over Eureka, both obtained by ECC type ozone sonde observations, were high throughout the winter to early spring of 1997/98 in contrast to those in the former 3 years. The situation is discussed in relation to the relative location of Eureka with respect to the polar vortex boundary and the chemical ozone loss inside the polar vortex. In 1997/98,Eureka was inside the polar vortex in the lower stratosphere (475K potential temperature level) only in the middle of December, early to mid-February and early to mid-March. The period was shorter than in the former 3 years. Moreover, daily T_<50> values when the lower stratosphere over Eureka was inside the polar vortex were not so low compared with those in the former 3 years, and PSCs were not observed over Eureka. The year to year variation of the temperatures in the lower stratosphere (T_<50>) over Eureka inside the polar vortex was generally consistent with the variation of the one within the entire polar vortex. A positive correlation between intravortex potential vorticity (PV) and ozone mixing ratio is expected in the lower stratosphere in the absence of strong chemical ozone loss. In 1997/98,this relation seems to have held during the winter to early spring over Eureka. Also, the total ozone in 1997/98 over Eureka when Eureka was inside the polar vortex in the lower stratosphere was higher than in the former 3 years. These suggest that the chemical ozone loss in 1997/98 inside the polar vortex was small in contrast to the former 3 years.