Some pointers to additional information about the SPADE campaign.
The following paper gives an overview of the SPADE campaign. The same issue of GRL contains several other papers which present results from the campaign.
Wofsy, S.C., Cohen, R.C., Schmeltekopf, A.L. Overview - The Stratospheric Photochemistry Aerosols and Dynamics Expedition (SPADE) and Airborne Arctic Stratospheric Expedition-II (AASE-II). Geophys. Res. Lett. 21, 23, pp. 2535-2538 (1994).