Comments on the recent decrease in solar radiation at the South Pole

A study has been made of the decrease in intensity of the direct solar radiation at the South Pole which occurred in late 1963. The decrease has been ascribed to an influx of volcanic dust in the stratosphere from the eruption of Mt. Agung, Bali. Following the decrease in 1963, the direct solar radiation values gradually approached their normal value by February 1966. Measurements of the total solar radiation received at the surface show a much smaller decrease. The solar radiation budget during this period is discussed and the influence of the dust on the radiation examined. Air trajectories at several stratospheric levels were used to indicate the height of the influx over the South Pole and the probable source region of the aerosol outside the Antarctic continental limits.