Steady state snow and firn density model

Calculates steady state snow/firn depth density profiles using Herron-Langway type models.

[rho,zieq]=densitymodel(Tavg,bdot,rhos,z,model)

Herron-Langway type models. (Arthern et al. 2010 formulation).

INPUT:
Tavg: 10m temperature in celcius
bdot: accumulation rate in mwe/yr or (kg/m2/yr)
rhos: surface density in kg/m3
z: depth in true_metres

model can be: {'HLJohnsen' 'HerronLangway' 'LiZwally' 'Helsen' 'NabarroHerring'}
default is herronlangway. (The other models are tuned for non-stationary modelling (Read Arthern et al.2010 before applying in steady state).


OUTPUT:
rho: density (kg/m3) for all z-values.
zieq: ice equivalent depth for all z-values.
t: age for all z-values (only taking densification into account.)

Example usage:
z=0:300;
[rho,zieq,t]=densitymodel(-31.5,177,340,z,'HerronLangway');
plot(z,rho)

Aslak Grinsted 2010