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127,044,000 Yen (FY1998; 40,166,000 Yen)
The 1996197 Arctic vortex was unusual in that it formed late and remained late in spring, and in that it brought record low column ozone in spring. Chemical ozone loss in the Arctic stratospheric vortex in February and March 1997 is estimated using ozone data of ILAS and ozonesonde. Both analyses show that the integrated ozone loss showed its maximum in the lower stratosphere with about 50 % loss during the two months from February to March 1997. The analyses of total reactive nitrogen (NOy) and nitrous oxide (N2O) data obtained by balloon experiments in the Arctic in February 1997 show that the effect of dynamical processes must be taken into account in quantitatively assessing the degree of denitrification and ozone loss, especially at high altitudes with N2O values lower than 120 ppbv. A vertical sandwich structure of Type IPSCs, in which layers of relative depolarization are above and below a scattering layer, has frequently been observed in the Arctic by lidar when the stratospheric temperature decreases to near the frost point of ice, and the mechanism of its formation is discussed. A high-sensitive in situ CIO measurement system for balloons and aircraft was developed using the principle based on chemical reactions and a resonance fluorescence technique, and a prototype model made was sufficient for the detection of stratospheric CIO radicals. Other various observational studies were made.
Polar vortex, Stratosphere, Ozone decrease, Denitrification, Dynamical mixing, PSC, Balloon observation, Satellite observation