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The backward form of the equations for the boundary conditions at the
soil surface are
Backward direction: z 0
j = 1
(A-16)
energy:
(A-17)
water:
dzj
^j,n+l = 0j+l,m-l+ J Dj7]pnfl
(A-18)
vapor:
The above equations were used to represent the partial differential
equations which describe the energy and mass transfer within the soil.
After a complete cycle through the nodes, from node 1 to node nc, then
from node nc back to node 1, all of the equations had been solved using
the most recent values of the state variables.