  We clarify the quantitative nature of the cosmological evolution of a global
string network, that is, the energy density, peculiar velocity, velocity
squared, Lorentz factor, formation rate of loops, and emission rate of
Nambu-Goldstone bosons, based on a new type of numerical simulation of scalar
fields in Eulerian meshes. We give a detailed explanation of a method to
extract the above-mentioned quantities to characterize string evolution by
analyzing scalar fields in Eulerian meshes from a Lagrangian viewpoint. We
confirm our previous claim that the number of long strings per horizon volume
in a global string network is smaller than in the case of a local string
network by a factor of $\sim$10 even under cosmological situations, and its
reason is clarified.
