Figure 3

(a) 500 hPa atmospheric circulation characteristics and distribution diagram of the volcanic dust curtain and aerosol layer in the mid-high latitudes of the Northern Hemisphere in April 1988; (b) schematic diagram of the atmospheric circulation characteristics of the 500 hPa layer from 40 to 90° N and distribution of the volcanic dust curtain and aerosol layer in December 1988; (c) atmospheric circulation characteristics of the 500 hPa layer from 30 to 90° N in January 1989; (d) potential height field anomaly distribution of the 500 hPa layer from 30 to 90° N in January 1989.