Some measurement results on sulfate aerosol concentration in and above a pine canopy

Profile of agate aerosol (SO42-) concentration was measured for four days a six heights in and above a 15m-high canopy of pine plantation during 6th a nd 10th August 1999. The concentration was the lowest (about 2 nmol/m(3)) o n 6th, and gradually increased to 9th showing the maximum values of about 1 3 nmol/m(3), and then decreased to 2 nmol/m(3) on 10th. The vertical profil es of SO42- concentration. showed mostly higher in the canopy than above th e canopy. As for the vertical profiles above the canopy on 8th and 10th, th e minimum was observed just above the canopy (16m), showing SO42- transport from the upper air layer to the canopy. While on 9th the profiles that are higher concentration just above the canopy and lower at the upper air laye r were observed, suggesting SO42- emission from the canopy to the upper air layer.