AIRBORNE OBSERVATIONS OF SO2, HCL, AND O3 IN THE STRATOSPHERIC PLUME OF THE PINATUBO VOLCANO IN JULY 1991

We have used a high resolution infrared spectrometer aboard the NASA Wallops Flight Facility Electra aircraft to measure the total column amount Of SO2, O3, and HCI above the aircraft while flying over the Caribbean three weeks after the June 15 eruption of Mt. Pinatubo in the Philippines. South of 20-degrees-N latitude we observed columns of SO2 ranging from 2.0 x 10(16) to 3.7 x 10(16) molecules-cm-2. In addition, the column amount of HCl averaged 1.5 x 10(15) molecules-cm-2 in the region of the plume. This may represent a small increase in HCl above the amount, estimated from our previous measurements, that would have been present had there been no volcanic eruption, but the increase is substantially less than that seen following the 1982 eruptions of El Chichon [Mankin and Coffey, 1984].