the axial viscosity is the viscosity of the dash-

pot of the Maxwell model. The compactive vis-

cosity is determined either from the results of

The plot of the data for both static and dy-

experiments in confined compression (uniaxial

namic measurements of Young's modulus for

strain), or from measurements of compaction as a

snow from Mellor (1975), supplemented by addi-

function of time for natural snowpacks.

tional data from Kuvaeva et al. (1967), is shown in

The data on axial viscosity are shown in Figure

Figure B1. In addition, the only data available

B3. The range of values for this parameter is large,

from dynamic or quasistatic determinations of

even allowing for the differences in the physical

Poisson's ratio for snow are also included in the

properties of polar and seasonal snow. It should

figure.

also be noted that, in addition to determining the

experiments in torsion and uniaxial tension and

used the results to determine the parameters for

the four-parameter viscoelastic fluid model for all

The difficulty of determining Poisson's ratio in

three loading modes. In addition, the data were

rapid-loading compression tests, coupled with the

used to define the viscosity of the lead dashpot of

extreme compressibility of low density snow, led

the model as a function of temperature and snow

density over the range of temperatures from 0 to

to the introduction in Bader et al. (1951) of the

40C and densities from 125300 kg/m3. Note

parameter called the "cross section number (the

reciprocal of Poisson's ratio)." Mellor (1975) iden-

that these results were used by Lang and

tified this parameter as the viscous equivalent of

Sommerfeld (1977).

Poisson's ratio and presented the available data

Mellor (1975) determined the compactive vis-

(Fig. B2).

cosity of seasonal snow from data from field mea-

Mellor (1975) separated the data on viscosity

surements by Kojima (1967), and both field and

into the categories of "axial" and "compactive"

laboratory studies by Keeler (1969a). He combined

viscosity. The former refers to the viscosity de-

these results with data for polar snow from Bader

termined from the "steady state" creep rate in

(1962b), experimental work by Mellor and

experiments under constant uniaxial compressive

Hendrickson (1965) and other field studies, into

his Figure 11 (p. 266). Ambach and Eisner (1985)

stress. In terms of the four-parameter model,

Yosida (1963)

Calcullatted ffromData bbyDeQQuervain1(1966)

u a ed rom Data y de uervain ( 966)

*Shinojima (1967)

Incompressible

0.5

Uniaxial Tension*

0.4

0.3

?

Bader et al.

0.2

(1951)

2

Data Summarized by Roch (1948)

0.1

Uniaxial

Compression*

0

200

400

600

800

1000

Density (kg m 3 )

27