Index: /issm/branches/trunk-jpl-damage/src/m/model/steadystateiceshelftemp.m
===================================================================
--- /issm/branches/trunk-jpl-damage/src/m/model/steadystateiceshelftemp.m	(revision 12563)
+++ /issm/branches/trunk-jpl-damage/src/m/model/steadystateiceshelftemp.m	(revision 12563)
@@ -0,0 +1,56 @@
+function temperature=steadystateiceshelftemp(md,surfacetemp,basaltemp)
+%STEADYSTATEICESHELFTEMP - compute depth-averaged steady-state temperature of an ice shelf 
+%
+%   This routine computes the depth-averaged temperature accounting for vertical advection 
+%   and diffusion of heat into the base of the ice shelf as a function of surface and 
+%   basal temperature and the basal melting rate.  Horizontal advection is ignored.
+%   The solution is a depth-averaged version of Equation 25 in Holland and Jenkins (1999).
+%
+%	 In addition to supplying md, the surface and basal temperatures of the ice shelf must
+%	 be supplied to the function IN DEGREES CELSIUS.  These temperatures can be supplied at 
+%	 each vertex of the mesh or as a single constant value to be used at every vertex.  
+%
+%	 The model md must also contain the fields: 
+%	 md.geometry.thickness
+%	 md.basalforcings.melting_rate
+
+%   Usage:
+%      temperature=steadystateiceshelftemp(md)
+
+if (length(md.geometry.thickness)~=md.mesh.numberofvertices)
+	error(['steadystateiceshelftemp error message: thickness should have a length of ' num2str(md.mesh.numberofvertices)])
+end
+
+%surface and basal temperatures in degrees C
+if (length(surfacetemp)==md.mesh.numberofvertices)
+	Ts=surfacetemp;
+elseif (length(surfacetemp)==1) 
+	Ts=surfacetemp*ones(md.mesh.numberofvertices,1);
+else
+	error(['steadystateiceshelftemp error message: surfacetemp should have a length of 1 or ' num2str(md.mesh.numberofvertices)])
+end
+
+if (length(basaltemp)==md.mesh.numberofvertices)
+	Tb=basaltemp;
+elseif (length(basaltemp)==1) 
+	Tb=basaltemp*ones(md.mesh.numberofvertices,1);
+else
+	error(['steadystateiceshelftemp error message: basaltemp should have a length of 1 or ' num2str(md.mesh.numberofvertices)])
+end
+
+Hi=md.geometry.thickness;
+ki=1.14e-6*md.constants.yts; % ice shelf thermal diffusivity from Holland and Jenkins (1999) converted to m^2/yr 
+
+%vertical velocity of ice shelf, positive for melting (thus minus sign)
+wi=-md.materials.rho_water/md.materials.rho_ice.*md.basalforcings.melting_rate; 
+
+%temperature profile is linear if melting rate is zero, depth-averaged temp is simple average in this case
+md.initialization.temperature=(Ts+Tb)/2;  % where wi~=0
+
+pos=find(abs(wi)>=1e-4); % to avoid division by zero
+
+%calculate depth-averaged temperature
+temperature(pos)=-( (Tb(pos)-Ts(pos))*ki./wi(pos) + Hi(pos).*Tb(pos) - (Hi(pos).*Ts(pos) + (Tb(pos)-Ts(pos))*ki./wi(pos)).*exp(Hi(pos).*wi(pos)/ki) )./( Hi(pos).*(exp(Hi(pos).*wi(pos)/ki)-1));
+
+%convert to Kelvin
+temperature=temperature+273;