Snow at surface (rho ~300 kg/m^3) compacts to firn (close-off ~830 kg/m^3) over decades to centuries; Herron-Langway 1980 two-stage Arrhenius; pore close-off traps atmospheric gases for ice cores.
Snow at surface (rho ~300 kg/m^3) compacts to firn (close-off ~830 kg/m^3) over decades to centuries; Herron-Langway 1980 two-stage Arrhenius; pore close-off traps atmospheric gases for ice cores.