Based on density data and the above air and ice velocities. (Tab-separated table of data).
Radar Velocities
Table of velocities in m/us (or mm per ns)
Density formula
Density formula: rho = rho_ice - (rho_ice-rho_snow)exp(-1.9z/zt) where zt is the depth of the firn-ice transition. rho_ice= 0.917, rho_snow = 0.3 or so. This formula could easily be used to give a smooth estimate of velocity with depth.
Vostok velocity data
Based on density data and the above air and ice
velocities. (Tab-separated table of data).
The above curve doesn't contain a correction for temperature. However, the vostok temperature varies by about 20 deg C from top to bottom. (Tab-separated table of data).
The interannual ice layers vary from about 350 mm thick at the surface to abour 50 mm thick at 1000 m depth (more or less linearly), for the Camp Century ice core.