Getdiff

function getdiff
This function returns the diffusivity of ice flow for a point along the glacier. This is determined from $$D^{'}= -\frac{2fA}{n+2} \left({\rho\,g}\right)^{n} \left({H^{'}}\right)^{n+2}\left|{\frac{\delta\,s^{'}}{\delta\,x^{'}}}\right|^{n-1}$$

where standard symbols are defined in the definition page. The diffusivity is scaled and is determined on a staggered grid that has points positioned halfway between adjacent thickness grid points. The function is called for each staggered grid point in turn; this means that it is the responsibility of the calling routine to deal with branching in the system. This function is called from calcthck, which is described in the section Model dynamics and the returned information is held in array diffus.