Large scale magnetospheric-ionospheric cusp/LLBL dynamics as monitored by joint ground-based and space observations in the Greenland-Svalbard zone S. Massetti, M. Candidi and P. Cerulli-Irelli Istituto di Fisica dello Spazio Interplanetario IFSI-INAF, Roma -Italy A case study based on data obtained from our twin high-latitude auroral monitors in the Greenland-Svalbard zone is presented. The comparison between our twin monitors and the FUV auroral images collected by the IMAGE spacecraft, shows how joint ground-based observations can compete and complete satellite imaging. By means of data from the two Greenland magnetometer chains, and the particle precipitation data derived by low-altitude DMSP satellites, we describe the quasi-periodic behaviour of magnetospheric-ionospheric coupling occurring under high magnetic shear regime, driven by large IMF BY and near zero IMF BZ components. _______________ Presented at the 35th COSPAR Scientific Assembly, Paris, France, July 18-25, 2004.