diff --git a/CHANGELOG.md b/CHANGELOG.md
index ad75832..41bf48d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- Do not increment CO2_YEAR when it is a no-data-value. For Catchment simulations, exclude CatchCN-specific resource variables from LDAS.rc.
 - Bug fix and improved efficiency in matlab script for generation of mwRTM_param.
 - Changed EXPDIR to absolute path for POSTPROC_HIST>0 option to work.
 - Support HISTORY output of ASNOW alone from ENSAVG Gridcomp.
diff --git a/GEOSldas_App/ldas_setup b/GEOSldas_App/ldas_setup
index d977683..9b8117b 100755
--- a/GEOSldas_App/ldas_setup
+++ b/GEOSldas_App/ldas_setup
@@ -1166,6 +1166,13 @@ class LDASsetup:
                    ldasrcInp[keyn]= valn
                 if('catchcn' in self.catch):
                    ldasrcInp['CO2_MonthlyMean_DiurnalCycle_FILE']= '../input/CO2_MonthlyMean_DiurnalCycle.nc4'
+                else:
+                   # remove catchcn-specific entries that do not apply to catch model
+                   ldasrcInp.pop('DTCN',None)
+                   ldasrcInp.pop('ATM_CO2',None)
+                   ldasrcInp.pop('CO2',None)
+                   ldasrcInp.pop('CO2_YEAR',None)
+                   ldasrcInp.pop('PRESCRIBE_DVG',None)
 
                 # create restart item in RC
                 catch_ = self.catch.upper()
diff --git a/GEOSldas_App/lenkf_j_template.py b/GEOSldas_App/lenkf_j_template.py
index 9727111..b2524fc 100644
--- a/GEOSldas_App/lenkf_j_template.py
+++ b/GEOSldas_App/lenkf_j_template.py
@@ -788,19 +788,18 @@
    # update cap_restart
    # ##################
    
-   set CO2LINE = `grep -n -m 1 "CO2_YEAR" $HOMDIR/LDAS.rc | cut -d':' -f1`
+   set CO2_BEFORE = `grep CO2_YEAR: LDAS.rc | cut -d':' -f2`
    
-   if ( $CO2LINE >= 1 ) then
+   if ( $CO2_BEFORE >= 1 ) then
    
        # Update reference year for Carbon Tracker CO2
        ##############################################
        
-       set CO2_BEFORE = `sed -n "${{CO2LINE}}p;d" LDAS.rc | cut -d':' -f2`
        set CAP_BEFORE = `head -1 $HOMDIR/cap_restart | cut -c1-4` 
        @ DY = $CAP_BEFORE - $CO2_BEFORE
        @ CO2_AFTER = `head -1 cap_restart | cut -c1-4` - $DY
-       set CO2UPDATE = "CO2_YEAR: $CO2_AFTER"
-       sed -i "${{CO2LINE}} s|.*|$CO2UPDATE|" LDAS.rc
+       set CO2UPDATE = `echo "CO2_YEAR:  "$CO2_AFTER`
+       sed -i "/CO2_YEAR:/c\\$CO2UPDATE" LDAS.rc
        /bin/rm -f $HOMDIR//LDAS.rc
        /bin/cp -p LDAS.rc $HOMDIR/LDAS.rc
    endif