Effect of stratospheric ozone variations on UV radiation and on tropospheric ozone at high latitudes

A negative trend of stratospheric ozone has been observed especially at high southern and northern latitudes during the last 15 years. At the stations studied here a negative trend in total ozone Was detected during 1987-1994: -10% at Marambio (64 degrees S) and -12% at Sodankyla (67 degrees N). The strongest negative trend was detected during spring. Mostly a negative trend in tropospheric ozone was observed at the stations during the late winter to early summer period during recent years. Because stratospheric ozone is controlling the flux of solar UV-B radiation reaching troposphere, loss of stratospheric ozone may have a strong impact on the destruction and production reactions of tropospheric ozone. We have studied the ozone sounding records of 1988-1994 at Marambio, Antarctica (64 degrees S), and at Sodankyla Finland (67 degrees N), to find out observational evidence of tropospheric ozone changes due to stratospheric ozone variations. We have found that springtime stratospheric ozone loss has a pronounced impact on the upper tropospheric ozone at both hemispheres. Average ozone deviation of 12.8% from the 1988 to 1994 means in the 6- to 8-km layer has been observed in Antarctica during the months with stratospheric ozone loss and -10.0% in the Arctic, respectively. Daily total ozone records and radiative transfer calculations were used to study the UV-B doses reaching the troposphere.