T. I. Pulkkinen (1), M. Palmroth (1) and N. Yu. Ganushkina (1)

(1) Finnish Meteorological Institute, POBox 503, FIN-00101 Helsinki,Finland. 358-99294603

The four Cluster II spacecraft orbit around the Earth such that in early 2001

the orbit cuts through the dayside magnetosphere near the polar cusp, and

traverses the nightside auroral fieldlines between the plasma sheet and the

ionosphere. Observations made around the orbit will be used to examine on

one hand the porcesses related to solar wind - magnetosphere coupling in the

dayside bow shock, magnetosheath, magnetopause, and the polar cusps, and

on the other hand the processes related to nightside auroral region, especially

those associated with magnetospheric substorms and storms. In this talk we

combine several large-scale modeling methods to give the mesoscale Cluster

observations a large-scale context: The dayside processes are examined with

the help of a global MHD simulation, which uses solar wind input to compute

the dynamic evolution of the magnetosphere. On the other hand, the nightside

auroral processes are examined utilizing an empirical magnetic field model,

which can be tuned to best represent the tail field configuration during indi-vidual

events. Furthermore, applications of such empirical modeling techniques

to include also inner magnetosphere ring current variations during geomagnetic

storms are discussed.