Index: /issm/trunk-jpl/src/m/classes/basalforcings.m
===================================================================
--- /issm/trunk-jpl/src/m/classes/basalforcings.m	(revision 27575)
+++ /issm/trunk-jpl/src/m/classes/basalforcings.m	(revision 27576)
@@ -8,4 +8,5 @@
 		groundedice_melting_rate  = NaN;
 		floatingice_melting_rate  = NaN;
+		perturbation_melting_rate = NaN;
 		geothermalflux            = NaN;
 	end
@@ -26,4 +27,5 @@
 			fielddisplay(self,'groundedice_melting_rate','basal melting rate (positive if melting) [m/yr]');
 			fielddisplay(self,'floatingice_melting_rate','basal melting rate (positive if melting) [m/yr]');
+			fielddisplay(self,'perturbation_melting_rate','(optional) perturbation in basal melting rate under floating ice [m/yr]');
 			fielddisplay(self,'geothermalflux','geothermal heat flux [W/m^2]');
 
@@ -32,4 +34,5 @@
 			self.groundedice_melting_rate=project3d(md,'vector',self.groundedice_melting_rate,'type','node','layer',1); 
 			self.floatingice_melting_rate=project3d(md,'vector',self.floatingice_melting_rate,'type','node','layer',1); 
+			self.perturbation_melting_rate=project3d(md,'vector',self.perturbation_melting_rate,'type','node','layer',1); 
 			self.geothermalflux=project3d(md,'vector',self.geothermalflux,'type','node','layer',1); %bedrock only gets geothermal flux
 		end % }}}
@@ -74,4 +77,5 @@
 			WriteData(fid,prefix,'object',self,'fieldname','floatingice_melting_rate','format','DoubleMat','mattype',1,'scale',1./yts,'timeserieslength',md.mesh.numberofvertices+1,'yts',yts)
 			WriteData(fid,prefix,'object',self,'fieldname','geothermalflux','format','DoubleMat','mattype',1,'timeserieslength',md.mesh.numberofvertices+1,'yts',yts);
+			WriteData(fid,prefix,'object',self,'fieldname','perturbation_melting_rate','format','DoubleMat','name','md.basalforcings.perturbation_melting_rate','mattype',1,'scale',1./yts,'timeserieslength',md.mesh.numberofvertices+1,'yts',md.constants.yts)
 		end % }}}
 		function savemodeljs(self,fid,modelname) % {{{
@@ -79,4 +83,5 @@
 			writejs1Darray(fid,[modelname '.basalforcings.groundedice_melting_rate'],self.groundedice_melting_rate);
 			writejs1Darray(fid,[modelname '.basalforcings.floatingice_melting_rate'],self.floatingice_melting_rate);
+			writejs1Darray(fid,[modelname '.basalforcings.perturbation_melting_rate'],self.perturbation_melting_rate);
 			writejs1Darray(fid,[modelname '.basalforcings.geothermalflux'],self.geothermalflux);