Studies of the morphology and the hetelogeneous reactions of Arctic PSC over Spitsbergen

Many PSC events were observed by the lidar observations at Ny-Aalesund，Svalbard(79°N，12°W)。The sandwich structure found in the vertical profile of PSC，which was frequently observed when the stratospheric temperature was lowered near the frost point，is very characteristic.The enhancement of PSC was observed when stratospheric temperature decreased near the frost point.The peak value of the backscattering ratio of the PSC is 5 to 8，and the depolarization ratio is near zero.The peaks of depolarization were found at the top and bottom sides of the PSC scattering layer.In other words，a liquid layer of PSC was between the solid layer(Sandwich)。The backscattering did not enhance at the depolarization peaks.The scattering and depolarization are inversely correlated in the sandwich structure for the vertical direction。This inverse correlation was observed not only in the sandwich structure，but also in the almost all the PSC events。There was few events when the scattering and depolarization were increased simultaneously.The numerical simulations of the lidar observations show some important suggestions for the microphysical processes of PSC。The simulations indicate that the parts of the characteristics of PSC can be explained by the ternary solution of H2SO4/HNO3/H2O。The observations were well simulated only when the number concentration of solid particles are between 10 I D1-3个D1 and 10个D1-2个D1/cc。

Many PSC events were observed by the lidar observations at Ny-Aalesund, Svalbard (79゜N, 12゜W). The sandwich structure found in the vertical profile of PSC, which was frequently observed when the stratospheric temperature was lowered near the frost point, is very characteristic.The enhancement of PSC was observed when stratospheric temperature decreased near the frost point. The peak value of the backscattering ratio of the PSC is 5 to 8, and the depolarization ratio is near zero. The peaks of depolarization were found at the top and bottom sides of the PSC scattering layer. In other words, a liquid layer of PSC was between the solid layer (sandwich). The backscattering did not enhance at the depolarization peaks.The scattering and depolarization are inversely correlated in the sandwich structure for the vertical direction. This inverse correlation was observed not only in the sandwich structure, but also in the almost all the PSC events. There was few events when the scattering and depolarization were increased simultaneously.The numerical simulations of the lidar observations show some important suggestions for the microphysical processes of PSC. The simulations indicate that the parts of the characteristics of PSC can be explained by the ternary solution of H2SO4/HNO3/H2O. The observations were well simulated only when the number concentration of solid particles are between 10ィイD1-3ィエD1 and 10ィイD1-2ィエD1 /cc.