function lh = latent_heat(t)
%function lh = latent_heat(t)
%lh is the latent heat of vaporisation of water at t degrees celsius.
%The units are Joules/kg.  It uses equation (A4.9) of Gill (1982).

%     Copyright J. V. Mansbridge, CSIRO, september 29 1993

lh = 2.5008e+6 - 2.3e+3*t;
