diff --git a/cime_config/config_grids.xml b/cime_config/config_grids.xml
index 45f886588e2b..c603ccac2d82 100755
--- a/cime_config/config_grids.xml
+++ b/cime_config/config_grids.xml
@@ -426,6 +426,16 @@
       <mask>SOwISC12to30E3r3</mask>
     </model_grid>
 
+    <model_grid alias="T62_SOwISC12to30E3r4" compset="(DATM|XATM|SATM)">
+      <grid name="atm">T62</grid>
+      <grid name="lnd">T62</grid>
+      <grid name="ocnice">SOwISC12to30E3r4</grid>
+      <grid name="rof">rx1</grid>
+      <grid name="glc">null</grid>
+      <grid name="wav">null</grid>
+      <mask>SOwISC12to30E3r4</mask>
+    </model_grid>
+
     <model_grid alias="TL319_oQU240wLI" compset="(DATM|XATM|SATM)">
       <grid name="atm">TL319</grid>
       <grid name="lnd">TL319</grid>
@@ -676,6 +686,16 @@
       <mask>SOwISC12to30E3r3</mask>
     </model_grid>
 
+    <model_grid alias="TL319_SOwISC12to30E3r4" compset="(DATM|XATM|SATM)">
+      <grid name="atm">TL319</grid>
+      <grid name="lnd">TL319</grid>
+      <grid name="ocnice">SOwISC12to30E3r4</grid>
+      <grid name="rof">JRA025</grid>
+      <grid name="glc">null</grid>
+      <grid name="wav">null</grid>
+      <mask>SOwISC12to30E3r4</mask>
+    </model_grid>
+
     <model_grid alias="TL319_oRRS18to6v3" compset="(DATM|XATM|SATM)">
       <grid name="atm">TL319</grid>
       <grid name="lnd">TL319</grid>
@@ -1430,6 +1450,16 @@
       <mask>SOwISC12to30E3r3</mask>
     </model_grid>
 
+    <model_grid alias="ne30pg2_SOwISC12to30E3r4">
+      <grid name="atm">ne30np4.pg2</grid>
+      <grid name="lnd">ne30np4.pg2</grid>
+      <grid name="ocnice">SOwISC12to30E3r4</grid>
+      <grid name="rof">r05</grid>
+      <grid name="glc">null</grid>
+      <grid name="wav">null</grid>
+      <mask>SOwISC12to30E3r4</mask>
+    </model_grid>
+
     <model_grid alias="northamericax4v1_r0125_northamericax4v1" compset="(DOCN|XOCN|SOCN|AQP1)">
       <grid name="atm">ne0np4_northamericax4v1</grid>
       <grid name="lnd">r0125</grid>
@@ -2171,6 +2201,16 @@
       <mask>IcoswISC30E3r5</mask>
     </model_grid>
 
+    <model_grid alias="TL319_SOwISC12to30E3r4_ais4to20" compset="_MALI">
+      <grid name="atm">TL319</grid>
+      <grid name="lnd">TL319</grid>
+      <grid name="ocnice">SOwISC12to30E3r4</grid>
+      <grid name="rof">JRA025</grid>
+      <grid name="glc">mpas.ais4to20km</grid>
+      <grid name="wav">null</grid>
+      <mask>SOwISC12to30E3r4</mask>
+    </model_grid>
+
     <!-- new runoff grids for data runoff model DROF -->
 
     <model_grid alias="T31_g37_rx1" compset="_DROF">
@@ -2547,6 +2587,16 @@
       <mask>SOwISC12to30E3r3</mask>
     </model_grid>
 
+    <model_grid alias="ne30pg2_r05_SOwISC12to30E3r4">
+      <grid name="atm">ne30np4.pg2</grid>
+      <grid name="lnd">r05</grid>
+      <grid name="ocnice">SOwISC12to30E3r4</grid>
+      <grid name="rof">r05</grid>
+      <grid name="glc">null</grid>
+      <grid name="wav">null</grid>
+      <mask>SOwISC12to30E3r4</mask>
+    </model_grid>
+
     <model_grid alias="ne30pg2_r05_WC14to60E2r3">
       <grid name="atm">ne30np4.pg2</grid>
       <grid name="lnd">r05</grid>
@@ -2859,6 +2909,7 @@
       <file grid="atm|lnd" mask="IcoswISC30E3r5">$DIN_LOC_ROOT/share/domains/domain.lnd.T62_IcoswISC30E3r5.231121.nc</file>
       <file grid="atm|lnd" mask="RRSwISC6to18E3r5">$DIN_LOC_ROOT/share/domains/domain.lnd.T62_RRSwISC6to18E3r5.240328.nc</file>
       <file grid="atm|lnd" mask="SOwISC12to30E3r3">$DIN_LOC_ROOT/share/domains/domain.lnd.T62_SOwISC12to30E3r3.240808.nc</file>
+      <file grid="atm|lnd" mask="SOwISC12to30E3r4">$DIN_LOC_ROOT/share/domains/domain.lnd.T62_SOwISC12to30E3r4.250122.nc</file>
       <desc>T62 is Gaussian grid:</desc>
     </domain>
 
@@ -2919,6 +2970,8 @@
       <file grid="ice|ocn" mask="RRSwISC6to18E3r5">$DIN_LOC_ROOT/share/domains/domain.ocn.TL319_RRSwISC6to18E3r5.240328.nc</file>
       <file grid="atm|lnd" mask="SOwISC12to30E3r3">$DIN_LOC_ROOT/share/domains/domain.lnd.TL319_SOwISC12to30E3r3.240808.nc</file>
       <file grid="ice|ocn" mask="SOwISC12to30E3r3">$DIN_LOC_ROOT/share/domains/domain.ocn.TL319_SOwISC12to30E3r3.240808.nc</file>
+      <file grid="atm|lnd" mask="SOwISC12to30E3r4">$DIN_LOC_ROOT/share/domains/domain.lnd.TL319_SOwISC12to30E3r4.250122.nc</file>
+      <file grid="ice|ocn" mask="SOwISC12to30E3r4">$DIN_LOC_ROOT/share/domains/domain.ocn.TL319_SOwISC12to30E3r4.250122.nc</file>
       <file grid="atm|lnd" mask="oRRS18to6v3">$DIN_LOC_ROOT/share/domains/domain.lnd.TL319_oRRS18to6v3.220124.nc</file>
       <file grid="ice|ocn" mask="oRRS18to6v3">$DIN_LOC_ROOT/share/domains/domain.ocn.TL319_oRRS18to6v3.220124.nc</file>
       <desc>TL319 is JRA lat/lon grid:</desc>
@@ -3042,6 +3095,8 @@
       <file grid="ice|ocn" mask="RRSwISC6to18E3r5">$DIN_LOC_ROOT/share/domains/domain.ocn.ne30pg2_RRSwISC6to18E3r5.240328.nc</file>
       <file grid="atm|lnd" mask="SOwISC12to30E3r3">$DIN_LOC_ROOT/share/domains/domain.lnd.ne30pg2_SOwISC12to30E3r3.240808.nc</file>
       <file grid="ice|ocn" mask="SOwISC12to30E3r3">$DIN_LOC_ROOT/share/domains/domain.ocn.ne30pg2_SOwISC12to30E3r3.240808.nc</file>
+      <file grid="atm|lnd" mask="SOwISC12to30E3r4">$DIN_LOC_ROOT/share/domains/domain.lnd.ne30pg2_SOwISC12to30E3r4.250122.nc</file>
+      <file grid="ice|ocn" mask="SOwISC12to30E3r4">$DIN_LOC_ROOT/share/domains/domain.ocn.ne30pg2_SOwISC12to30E3r4.250122.nc</file>
       <file grid="atm|lnd" mask="gx1v6">$DIN_LOC_ROOT/share/domains/domain.lnd.ne30pg2_gx1v6.190806.nc</file>
       <file grid="ice|ocn" mask="gx1v6">$DIN_LOC_ROOT/share/domains/domain.ocn.ne30pg2_gx1v6.190806.nc</file>
       <desc>ne30np4.pg2 is Spectral Elem 1-deg grid w/ 2x2 FV physics grid per element:</desc>
@@ -3369,6 +3424,13 @@
       <desc>SOwISC12to30E3r3 is a MPAS ocean grid generated with the jigsaw/compass process using XXXXX. Additionally, it has ocean in ice-shelf cavities:</desc>
     </domain>
 
+    <domain name="SOwISC12to30E3r4">
+      <nx>807754</nx>
+      <ny>1</ny>
+      <file grid="ice|ocn">$DIN_LOC_ROOT/share/domains/domain.ocn.SOwISC12to30E3r4.250122.nc</file>
+      <desc>SOwISC12to30E3r4 is a MPAS ocean grid generated with the jigsaw/compass process using XXXXX. Additionally, it has ocean in ice-shelf cavities:</desc>
+    </domain>
+
     <!-- ROF (river) grids-->
 
     <domain name="r2">
@@ -3407,6 +3469,8 @@
       <file grid="lnd" mask="RRSwISC6to18E3r5">$DIN_LOC_ROOT/share/domains/domain.lnd.r05_RRSwISC6to18E3r5.240328.nc</file>
       <file grid="atm" mask="SOwISC12to30E3r3">$DIN_LOC_ROOT/share/domains/domain.lnd.r05_SOwISC12to30E3r3.240808.nc</file>
       <file grid="lnd" mask="SOwISC12to30E3r3">$DIN_LOC_ROOT/share/domains/domain.lnd.r05_SOwISC12to30E3r3.240808.nc</file>
+      <file grid="atm" mask="SOwISC12to30E3r4">$DIN_LOC_ROOT/share/domains/domain.lnd.r05_SOwISC12to30E3r4.250122.nc</file>
+      <file grid="lnd" mask="SOwISC12to30E3r4">$DIN_LOC_ROOT/share/domains/domain.lnd.r05_SOwISC12to30E3r4.250122.nc</file>
       <file grid="lnd" mask="gx1v6">$DIN_LOC_ROOT/share/domains/domain.lnd.r05_gx1v6.191014.nc</file>
       <desc>r05 is 1/2 degree river routing grid:</desc>
     </domain>
@@ -3947,6 +4011,16 @@
       <map name="ATM2OCN_FMAPNAME_NONLINEAR">cpl/gridmaps/ne30pg2/map_ne30pg2_to_SOwISC12to30E3r3_trfvnp2.20240808.nc</map>
     </gridmap>
 
+    <gridmap atm_grid="ne30np4.pg2" ocn_grid="SOwISC12to30E3r4">
+      <map name="ATM2OCN_FMAPNAME">cpl/gridmaps/ne30pg2/map_ne30pg2_to_SOwISC12to30E3r4_traave.20250122.nc</map>
+      <map name="ATM2OCN_VMAPNAME">cpl/gridmaps/ne30pg2/map_ne30pg2_to_SOwISC12to30E3r4_trbilin.20250122.nc</map>
+      <map name="ATM2OCN_SMAPNAME">cpl/gridmaps/ne30pg2/map_ne30pg2_to_SOwISC12to30E3r4-nomask_trbilin.20250122.nc</map>
+      <map name="OCN2ATM_FMAPNAME">cpl/gridmaps/SOwISC12to30E3r4/map_SOwISC12to30E3r4_to_ne30pg2_traave.20250122.nc</map>
+      <map name="OCN2ATM_SMAPNAME">cpl/gridmaps/SOwISC12to30E3r4/map_SOwISC12to30E3r4_to_ne30pg2_traave.20250122.nc</map>
+      <map name="ATM2ICE_FMAPNAME_NONLINEAR">cpl/gridmaps/ne30pg2/map_ne30pg2_to_SOwISC12to30E3r4_trfvnp2.20250122.nc</map>
+      <map name="ATM2OCN_FMAPNAME_NONLINEAR">cpl/gridmaps/ne30pg2/map_ne30pg2_to_SOwISC12to30E3r4_trfvnp2.20250122.nc</map>
+    </gridmap>
+
     <gridmap atm_grid="ne30np4.pg3" ocn_grid="oEC60to30v3">
       <map name="ATM2OCN_FMAPNAME">cpl/gridmaps/ne30pg3/map_ne30pg3_to_oEC60to30v3_mono.200331.nc</map>
       <map name="ATM2OCN_VMAPNAME">cpl/gridmaps/ne30pg3/map_ne30pg3_to_oEC60to30v3_bilin.200331.nc</map>
@@ -4764,6 +4838,14 @@
       <map name="OCN2ATM_SMAPNAME">cpl/gridmaps/SOwISC12to30E3r3/map_SOwISC12to30E3r3_to_T62_traave.20240808.nc</map>
     </gridmap>
 
+    <gridmap atm_grid="T62" ocn_grid="SOwISC12to30E3r4">
+      <map name="ATM2OCN_FMAPNAME">cpl/gridmaps/T62/map_T62_to_SOwISC12to30E3r4_traave.20250122.nc</map>
+      <map name="ATM2OCN_SMAPNAME">cpl/gridmaps/T62/map_T62_to_SOwISC12to30E3r4-nomask_trbilin.20250122.nc</map>
+      <map name="ATM2OCN_VMAPNAME">cpl/gridmaps/T62/map_T62_to_SOwISC12to30E3r4_esmfpatch.20250122.nc</map>
+      <map name="OCN2ATM_FMAPNAME">cpl/gridmaps/SOwISC12to30E3r4/map_SOwISC12to30E3r4_to_T62_traave.20250122.nc</map>
+      <map name="OCN2ATM_SMAPNAME">cpl/gridmaps/SOwISC12to30E3r4/map_SOwISC12to30E3r4_to_T62_traave.20250122.nc</map>
+    </gridmap>
+
     <gridmap atm_grid="TL319" ocn_grid="oQU240wLI">
       <map name="ATM2OCN_FMAPNAME">cpl/gridmaps/TL319/map_TL319_to_oQU240wLI_traave.20240509.nc</map>
       <map name="ATM2OCN_SMAPNAME">cpl/gridmaps/TL319/map_TL319_to_oQU240wLI-nomask_trbilin.20240509.nc</map>
@@ -4924,6 +5006,14 @@
       <map name="OCN2ATM_SMAPNAME">cpl/gridmaps/SOwISC12to30E3r3/map_SOwISC12to30E3r3_to_TL319_traave.20240808.nc</map>
     </gridmap>
 
+    <gridmap atm_grid="TL319" ocn_grid="SOwISC12to30E3r4">
+      <map name="ATM2OCN_FMAPNAME">cpl/gridmaps/TL319/map_TL319_to_SOwISC12to30E3r4_traave.20250122.nc</map>
+      <map name="ATM2OCN_SMAPNAME">cpl/gridmaps/TL319/map_TL319_to_SOwISC12to30E3r4-nomask_trbilin.20250122.nc</map>
+      <map name="ATM2OCN_VMAPNAME">cpl/gridmaps/TL319/map_TL319_to_SOwISC12to30E3r4_esmfpatch.20250122.nc</map>
+      <map name="OCN2ATM_FMAPNAME">cpl/gridmaps/SOwISC12to30E3r4/map_SOwISC12to30E3r4_to_TL319_traave.20250122.nc</map>
+      <map name="OCN2ATM_SMAPNAME">cpl/gridmaps/SOwISC12to30E3r4/map_SOwISC12to30E3r4_to_TL319_traave.20250122.nc</map>
+    </gridmap>
+
     <gridmap atm_grid="TL319" ocn_grid="oRRS18to6v3">
       <map name="ATM2OCN_FMAPNAME">cpl/gridmaps/TL319/map_TL319_to_oRRS18to6v3_aave.220124.nc</map>
       <map name="ATM2OCN_SMAPNAME">cpl/gridmaps/TL319/map_TL319_to_oRRS18to6v3_bilin.220124.nc</map>
@@ -5364,6 +5454,10 @@
       <map name="OCN2ROF_SMAPNAME">cpl/gridmaps/SOwISC12to30E3r3/map_SOwISC12to30E3r3_to_r05_traave.20240808.nc</map>
     </gridmap>
 
+    <gridmap rof_grid="r05" ocn_grid="SOwISC12to30E3r4">
+      <map name="OCN2ROF_SMAPNAME">cpl/gridmaps/SOwISC12to30E3r4/map_SOwISC12to30E3r4_to_r05_traave.20250122.nc</map>
+    </gridmap>
+
     <gridmap rof_grid="r05" ocn_grid="EC30to60E2r2">
       <map name="OCN2ROF_SMAPNAME">cpl/cpl6/map_EC30to60E2r2_to_r05_neareststod.220728.nc</map>
     </gridmap>
@@ -5484,6 +5578,11 @@
       <map name="ROF2OCN_LIQ_RMAPNAME">cpl/cpl6/map_rx1_to_SOwISC12to30E3r3_cstmnn.r150e300.20240808.nc</map>
     </gridmap>
 
+    <gridmap ocn_grid="SOwISC12to30E3r4" rof_grid="rx1">
+      <map name="ROF2OCN_ICE_RMAPNAME">cpl/cpl6/map_rx1_to_SOwISC12to30E3r4_r150e300.cstmnn.20250122.nc</map>
+      <map name="ROF2OCN_LIQ_RMAPNAME">cpl/cpl6/map_rx1_to_SOwISC12to30E3r4_r150e300.cstmnn.20250122.nc</map>
+    </gridmap>
+
     <gridmap ocn_grid="oQU240wLI" rof_grid="JRA025">
       <map name="ROF2OCN_ICE_RMAPNAME">cpl/cpl6/map_JRA025_to_oQU240wLI_cstmnn.r150e300.20240516.nc</map>
       <map name="ROF2OCN_LIQ_RMAPNAME">cpl/cpl6/map_JRA025_to_oQU240wLI_cstmnn.r150e300.20240516.nc</map>
@@ -5584,6 +5683,11 @@
       <map name="ROF2OCN_LIQ_RMAPNAME">cpl/cpl6/map_JRA025_to_SOwISC12to30E3r3_cstmnn.r150e300.20240808.nc</map>
     </gridmap>
 
+    <gridmap ocn_grid="SOwISC12to30E3r4" rof_grid="JRA025">
+      <map name="ROF2OCN_ICE_RMAPNAME">cpl/cpl6/map_JRA025_to_SOwISC12to30E3r4_r150e300.cstmnn.20250122.nc</map>
+      <map name="ROF2OCN_LIQ_RMAPNAME">cpl/cpl6/map_JRA025_to_SOwISC12to30E3r4_r150e300.cstmnn.20250122.nc</map>
+    </gridmap>
+
     <gridmap ocn_grid="oRRS18to6v3" rof_grid="JRA025">
       <map name="ROF2OCN_ICE_RMAPNAME">cpl/cpl6/map_JRA025_to_oRRS18to6v3_smoothed.r50e100.220124.nc</map>
       <map name="ROF2OCN_LIQ_RMAPNAME">cpl/cpl6/map_JRA025_to_oRRS18to6v3_smoothed.r50e100.220124.nc</map>
@@ -5684,6 +5788,11 @@
       <map name="ROF2OCN_LIQ_RMAPNAME">cpl/cpl6/map_r05_to_SOwISC12to30E3r3_cstmnn.r150e300.20240808.nc</map>
     </gridmap>
 
+    <gridmap ocn_grid="SOwISC12to30E3r4" rof_grid="r05">
+      <map name="ROF2OCN_ICE_RMAPNAME">cpl/cpl6/map_r05_to_SOwISC12to30E3r4_r150e300.cstmnn.20250122.nc</map>
+      <map name="ROF2OCN_LIQ_RMAPNAME">cpl/cpl6/map_r05_to_SOwISC12to30E3r4_r150e300.cstmnn.20250122.nc</map>
+    </gridmap>
+
     <gridmap ocn_grid="IcoswISC30E3r5" rof_grid="r025">
       <map name="ROF2OCN_ICE_RMAPNAME">cpl/cpl6/map_r025_to_IcoswISC30E3r5_cstmnn.r150e300.20240401.nc</map>
       <map name="ROF2OCN_LIQ_RMAPNAME">cpl/cpl6/map_r025_to_IcoswISC30E3r5_cstmnn.r150e300.20240401.nc</map>
@@ -6068,6 +6177,17 @@
       <map name="GLC2OCN_ICE_RMAPNAME">cpl/gridmaps/mpas.ais4to20km/map_ais4to20_to_IcoswISC30E3r5_esmfnearestdtos.20240701.nc</map>
     </gridmap>
 
+    <gridmap glc_grid="mpas.ais4to20km" ocn_grid="SOwISC12to30E3r4">
+      <map name="OCN2GLC_SHELF_FMAPNAME">cpl/gridmaps/SOwISC12to30E3r4/map_SOwISC12to30E3r4-nomask_to_ais4to20_esmfaave.20250122.nc</map>
+      <map name="OCN2GLC_SHELF_SMAPNAME">cpl/gridmaps/SOwISC12to30E3r4/map_SOwISC12to30E3r4-nomask_to_ais4to20_esmfbilin.20250122.nc</map>
+      <map name="GLC2ICE_FMAPNAME">cpl/gridmaps/mpas.ais4to20km/map_ais4to20_to_SOwISC12to30E3r4-nomask_esmfaave.20250122.nc</map>
+      <map name="GLC2ICE_SMAPNAME">cpl/gridmaps/mpas.ais4to20km/map_ais4to20_to_SOwISC12to30E3r4-nomask_esmfbilin.20250122.nc</map>
+      <map name="GLC2OCN_FMAPNAME">cpl/gridmaps/mpas.ais4to20km/map_ais4to20_to_SOwISC12to30E3r4-nomask_esmfaave.20250122.nc</map>
+      <map name="GLC2OCN_SMAPNAME">cpl/gridmaps/mpas.ais4to20km/map_ais4to20_to_SOwISC12to30E3r4-nomask_esmfbilin.20250122.nc</map>
+      <map name="GLC2OCN_LIQ_RMAPNAME">cpl/gridmaps/mpas.ais4to20km/map_ais4to20_to_SOwISC12to30E3r4-nomask_esmfnearestdtos.20250122.nc</map>
+      <map name="GLC2OCN_ICE_RMAPNAME">cpl/gridmaps/mpas.ais4to20km/map_ais4to20_to_SOwISC12to30E3r4_esmfnearestdtos.20250122.nc</map>
+    </gridmap>
+
 
     <!-- ======================================================== -->
     <!-- GRIDS: glc to ocn mapping                                -->
diff --git a/components/elm/bld/namelist_files/namelist_definition.xml b/components/elm/bld/namelist_files/namelist_definition.xml
index 87a6da722af1..2c5d4067747a 100644
--- a/components/elm/bld/namelist_files/namelist_definition.xml
+++ b/components/elm/bld/namelist_files/namelist_definition.xml
@@ -1497,7 +1497,7 @@ Representative concentration pathway for future scenarios [radiative forcing at
 
 <entry id="mask" type="char*20" category="default_settings"
        group="default_settings"
-       valid_values="USGS,gx3v7,gx1v6,navy,test,tx0.1v2,tx1v1,T62,TL319,cruncep,oEC60to30v3,oEC60to30v3wLI,ECwISC30to60E1r2,EC30to60E2r2,WC14to60E2r3,WCAtl12to45E2r4,SOwISC12to60E2r4,ECwISC30to60E2r1,oRRS18to6,oRRS18to6v3,oRRS15to5,oARRM60to10,oARRM60to6,ARRM10to60E2r1,oQU480,oQU240,oQU240wLI,oQU120,oRRS30to10v3,oRRS30to10v3wLI,360x720cru,NLDASww3a,NLDAS,tx0.1v2,ICOS10,IcoswISC30E3r5,IcosXISC30E3r7,RRSwISC6to18E3r5,SOwISC12to30E3r3">
+       valid_values="USGS,gx3v7,gx1v6,navy,test,tx0.1v2,tx1v1,T62,TL319,cruncep,oEC60to30v3,oEC60to30v3wLI,ECwISC30to60E1r2,EC30to60E2r2,WC14to60E2r3,WCAtl12to45E2r4,SOwISC12to60E2r4,ECwISC30to60E2r1,oRRS18to6,oRRS18to6v3,oRRS15to5,oARRM60to10,oARRM60to6,ARRM10to60E2r1,oQU480,oQU240,oQU240wLI,oQU120,oRRS30to10v3,oRRS30to10v3wLI,360x720cru,NLDASww3a,NLDAS,tx0.1v2,ICOS10,IcoswISC30E3r5,IcosXISC30E3r7,RRSwISC6to18E3r5,SOwISC12to30E3r3,SOwISC12to30E3r4">
 Land mask description
 </entry>
 
diff --git a/components/mpas-ocean/bld/namelist_files/namelist_defaults_mpaso.xml b/components/mpas-ocean/bld/namelist_files/namelist_defaults_mpaso.xml
index 73d4eeecd526..b13e606a7fc5 100644
--- a/components/mpas-ocean/bld/namelist_files/namelist_defaults_mpaso.xml
+++ b/components/mpas-ocean/bld/namelist_files/namelist_defaults_mpaso.xml
@@ -56,6 +56,7 @@
 <config_dt ocn_grid="FRISwISC01to60E3r1">'00:01:00'</config_dt>
 <config_dt ocn_grid="RRSwISC6to18E3r5">'00:05:00'</config_dt>
 <config_dt ocn_grid="SOwISC12to30E3r3">'00:10:00'</config_dt>
+<config_dt ocn_grid="SOwISC12to30E3r4">'00:10:00'</config_dt>
 <config_time_integrator>'split_explicit_ab2'</config_time_integrator>
 <config_number_of_time_levels>2</config_number_of_time_levels>
 
@@ -87,6 +88,7 @@
 <config_hmix_scaleWithMesh ocn_grid="FRISwISC01to60E3r1">.true.</config_hmix_scaleWithMesh>
 <config_hmix_scaleWithMesh ocn_grid="RRSwISC6to18E3r5">.true.</config_hmix_scaleWithMesh>
 <config_hmix_scaleWithMesh ocn_grid="SOwISC12to30E3r3">.true.</config_hmix_scaleWithMesh>
+<config_hmix_scaleWithMesh ocn_grid="SOwISC12to30E3r4">.true.</config_hmix_scaleWithMesh>
 <config_maxMeshDensity>-1.0</config_maxMeshDensity>
 <config_hmix_use_ref_cell_width>.false.</config_hmix_use_ref_cell_width>
 <config_hmix_ref_cell_width>30.0e3</config_hmix_ref_cell_width>
@@ -110,6 +112,7 @@
 <config_use_mom_del2 ocn_grid="FRISwISC01to60E3r1">.true.</config_use_mom_del2>
 <config_use_mom_del2 ocn_grid="RRSwISC6to18E3r5">.true.</config_use_mom_del2>
 <config_use_mom_del2 ocn_grid="SOwISC12to30E3r3">.true.</config_use_mom_del2>
+<config_use_mom_del2 ocn_grid="SOwISC12to30E3r4">.true.</config_use_mom_del2>
 <config_mom_del2>10.0</config_mom_del2>
 <config_mom_del2 ocn_grid="oEC60to30v3">1000.0</config_mom_del2>
 <config_mom_del2 ocn_grid="oEC60to30v3wLI">1000.0</config_mom_del2>
@@ -127,6 +130,7 @@
 <config_mom_del2 ocn_grid="FRISwISC01to60E3r1">38.5</config_mom_del2>
 <config_mom_del2 ocn_grid="RRSwISC6to18E3r5">100.0</config_mom_del2>
 <config_mom_del2 ocn_grid="SOwISC12to30E3r3">462.0</config_mom_del2>
+<config_mom_del2 ocn_grid="SOwISC12to30E3r4">462.0</config_mom_del2>
 <config_use_tracer_del2>.false.</config_use_tracer_del2>
 <config_tracer_del2>10.0</config_tracer_del2>
 
@@ -159,6 +163,7 @@
 <config_mom_del4 ocn_grid="FRISwISC01to60E3r1">6.83e06</config_mom_del4>
 <config_mom_del4 ocn_grid="RRSwISC6to18E3r5">3.2e09</config_mom_del4>
 <config_mom_del4 ocn_grid="SOwISC12to30E3r3">1.18e10</config_mom_del4>
+<config_mom_del4 ocn_grid="SOwISC12to30E3r4">1.18e10</config_mom_del4>
 <config_mom_del4_div_factor>1.0</config_mom_del4_div_factor>
 <config_use_tracer_del4>.false.</config_use_tracer_del4>
 <config_tracer_del4>0.0</config_tracer_del4>
@@ -197,6 +202,7 @@
 <config_Redi_horizontal_taper ocn_grid="FRISwISC02to60E3r1">'RossbyRadius'</config_Redi_horizontal_taper>
 <config_Redi_horizontal_taper ocn_grid="FRISwISC01to60E3r1">'RossbyRadius'</config_Redi_horizontal_taper>
 <config_Redi_horizontal_taper ocn_grid="SOwISC12to30E3r3">'RossbyRadius'</config_Redi_horizontal_taper>
+<config_Redi_horizontal_taper ocn_grid="SOwISC12to30E3r4">'RossbyRadius'</config_Redi_horizontal_taper>
 <config_Redi_horizontal_ramp_min>20e3</config_Redi_horizontal_ramp_min>
 <config_Redi_horizontal_ramp_min ocn_grid="WCAtl12to45E2r4">30e3</config_Redi_horizontal_ramp_min>
 <config_Redi_horizontal_ramp_max>30e3</config_Redi_horizontal_ramp_max>
@@ -229,6 +235,7 @@
 <config_GM_closure ocn_grid="FRISwISC02to60E3r1">'N2_dependent'</config_GM_closure>
 <config_GM_closure ocn_grid="FRISwISC01to60E3r1">'N2_dependent'</config_GM_closure>
 <config_GM_closure ocn_grid="SOwISC12to30E3r3">'N2_dependent'</config_GM_closure>
+<config_GM_closure ocn_grid="SOwISC12to30E3r4">'N2_dependent'</config_GM_closure>
 <config_GM_constant_kappa>900.0</config_GM_constant_kappa>
 <config_GM_constant_kappa ocn_forcing="datm_forced_restoring" ocn_grid="oEC60to30v3wLI">600.0</config_GM_constant_kappa>
 <config_GM_constant_kappa ocn_forcing="datm_forced_restoring" ocn_grid="ECwISC30to60E1r2">600.0</config_GM_constant_kappa>
@@ -244,6 +251,7 @@
 <config_GM_constant_kappa ocn_forcing="datm_forced_restoring" ocn_grid="FRISwISC02to60E3r1">600.0</config_GM_constant_kappa>
 <config_GM_constant_kappa ocn_forcing="datm_forced_restoring" ocn_grid="FRISwISC01to60E3r1">600.0</config_GM_constant_kappa>
 <config_GM_constant_kappa ocn_forcing="datm_forced_restoring" ocn_grid="SOwISC12to30E3r3">600.0</config_GM_constant_kappa>
+<config_GM_constant_kappa ocn_forcing="datm_forced_restoring" ocn_grid="SOwISC12to30E3r4">600.0</config_GM_constant_kappa>
 <config_GM_constant_bclModeSpeed>0.3</config_GM_constant_bclModeSpeed>
 <config_GM_minBclModeSpeed_method>'constant'</config_GM_minBclModeSpeed_method>
 <config_GM_spatially_variable_min_kappa>300.0</config_GM_spatially_variable_min_kappa>
@@ -258,6 +266,7 @@
 <config_GM_spatially_variable_baroclinic_mode ocn_grid="FRISwISC02to60E3r1">1.0</config_GM_spatially_variable_baroclinic_mode>
 <config_GM_spatially_variable_baroclinic_mode ocn_grid="FRISwISC01to60E3r1">1.0</config_GM_spatially_variable_baroclinic_mode>
 <config_GM_spatially_variable_baroclinic_mode ocn_grid="SOwISC12to30E3r3">1.0</config_GM_spatially_variable_baroclinic_mode>
+<config_GM_spatially_variable_baroclinic_mode ocn_grid="SOwISC12to30E3r4">1.0</config_GM_spatially_variable_baroclinic_mode>
 <config_GM_Visbeck_alpha>0.13</config_GM_Visbeck_alpha>
 <config_GM_Visbeck_max_depth>1000.0</config_GM_Visbeck_max_depth>
 <config_GM_EG_riMin>200.0</config_GM_EG_riMin>
@@ -274,6 +283,7 @@
 <config_GM_horizontal_taper ocn_grid="FRISwISC02to60E3r1">'RossbyRadius'</config_GM_horizontal_taper>
 <config_GM_horizontal_taper ocn_grid="FRISwISC01to60E3r1">'RossbyRadius'</config_GM_horizontal_taper>
 <config_GM_horizontal_taper ocn_grid="SOwISC12to30E3r3">'RossbyRadius'</config_GM_horizontal_taper>
+<config_GM_horizontal_taper ocn_grid="SOwISC12to30E3r4">'RossbyRadius'</config_GM_horizontal_taper>
 <config_GM_horizontal_ramp_min>20e3</config_GM_horizontal_ramp_min>
 <config_GM_horizontal_ramp_min ocn_grid="WCAtl12to45E2r4">30e3</config_GM_horizontal_ramp_min>
 <config_GM_horizontal_ramp_max>30e3</config_GM_horizontal_ramp_max>
@@ -431,6 +441,7 @@
 <config_land_ice_flux_mode ocn_grid="FRISwISC01to60E3r1">'pressure_only'</config_land_ice_flux_mode>
 <config_land_ice_flux_mode ocn_grid="RRSwISC6to18E3r5">'pressure_only'</config_land_ice_flux_mode>
 <config_land_ice_flux_mode ocn_grid="SOwISC12to30E3r3">'pressure_only'</config_land_ice_flux_mode>
+<config_land_ice_flux_mode ocn_grid="SOwISC12to30E3r4">'pressure_only'</config_land_ice_flux_mode>
 <config_land_ice_flux_formulation>'Jenkins'</config_land_ice_flux_formulation>
 <config_land_ice_flux_useHollandJenkinsAdvDiff>.false.</config_land_ice_flux_useHollandJenkinsAdvDiff>
 <config_land_ice_flux_attenuation_coefficient>10.0</config_land_ice_flux_attenuation_coefficient>
@@ -451,6 +462,7 @@
 <config_land_ice_flux_explicit_topDragCoeff ocn_grid="FRISwISC01to60E3r1">4.48e-3</config_land_ice_flux_explicit_topDragCoeff>
 <config_land_ice_flux_explicit_topDragCoeff ocn_grid="RRSwISC6to18E3r5">4.48e-3</config_land_ice_flux_explicit_topDragCoeff>
 <config_land_ice_flux_explicit_topDragCoeff ocn_grid="SOwISC12to30E3r3">4.48e-3</config_land_ice_flux_explicit_topDragCoeff>
+<config_land_ice_flux_explicit_topDragCoeff ocn_grid="SOwISC12to30E3r4">4.48e-3</config_land_ice_flux_explicit_topDragCoeff>
 <config_land_ice_flux_ISOMIP_gammaT>1e-4</config_land_ice_flux_ISOMIP_gammaT>
 <config_land_ice_flux_jenkins_heat_transfer_coefficient>0.011</config_land_ice_flux_jenkins_heat_transfer_coefficient>
 <config_land_ice_flux_jenkins_heat_transfer_coefficient ocn_grid="oEC60to30v3wLI">0.00295</config_land_ice_flux_jenkins_heat_transfer_coefficient>
@@ -465,6 +477,7 @@
 <config_land_ice_flux_jenkins_heat_transfer_coefficient ocn_grid="FRISwISC01to60E3r1">0.00295</config_land_ice_flux_jenkins_heat_transfer_coefficient>
 <config_land_ice_flux_jenkins_heat_transfer_coefficient ocn_grid="RRSwISC6to18E3r5">0.00295</config_land_ice_flux_jenkins_heat_transfer_coefficient>
 <config_land_ice_flux_jenkins_heat_transfer_coefficient ocn_grid="SOwISC12to30E3r3">0.00295</config_land_ice_flux_jenkins_heat_transfer_coefficient>
+<config_land_ice_flux_jenkins_heat_transfer_coefficient ocn_grid="SOwISC12to30E3r4">0.00295</config_land_ice_flux_jenkins_heat_transfer_coefficient>
 <config_land_ice_flux_jenkins_salt_transfer_coefficient>3.1e-4</config_land_ice_flux_jenkins_salt_transfer_coefficient>
 <config_land_ice_flux_jenkins_salt_transfer_coefficient ocn_grid="oEC60to30v3wLI">8.42e-5</config_land_ice_flux_jenkins_salt_transfer_coefficient>
 <config_land_ice_flux_jenkins_salt_transfer_coefficient ocn_grid="ECwISC30to60E1r2">8.42e-5</config_land_ice_flux_jenkins_salt_transfer_coefficient>
@@ -478,6 +491,7 @@
 <config_land_ice_flux_jenkins_salt_transfer_coefficient ocn_grid="FRISwISC01to60E3r1">8.42e-5</config_land_ice_flux_jenkins_salt_transfer_coefficient>
 <config_land_ice_flux_jenkins_salt_transfer_coefficient ocn_grid="RRSwISC6to18E3r5">8.42e-5</config_land_ice_flux_jenkins_salt_transfer_coefficient>
 <config_land_ice_flux_jenkins_salt_transfer_coefficient ocn_grid="SOwISC12to30E3r3">8.42e-5</config_land_ice_flux_jenkins_salt_transfer_coefficient>
+<config_land_ice_flux_jenkins_salt_transfer_coefficient ocn_grid="SOwISC12to30E3r4">8.42e-5</config_land_ice_flux_jenkins_salt_transfer_coefficient>
 <config_land_ice_flux_tidal_Jourdain_alpha>1.0</config_land_ice_flux_tidal_Jourdain_alpha>
 <config_land_ice_flux_tidal_Jourdain_A0>0.0</config_land_ice_flux_tidal_Jourdain_A0>
 <config_land_ice_flux_tidal_Jourdain_U0>5e-2</config_land_ice_flux_tidal_Jourdain_U0>
@@ -511,6 +525,7 @@
 <config_implicit_top_drag_coeff ocn_grid="FRISwISC01to60E3r1">4.48e-3</config_implicit_top_drag_coeff>
 <config_implicit_top_drag_coeff ocn_grid="RRSwISC6to18E3r5">4.48e-3</config_implicit_top_drag_coeff>
 <config_implicit_top_drag_coeff ocn_grid="SOwISC12to30E3r3">4.48e-3</config_implicit_top_drag_coeff>
+<config_implicit_top_drag_coeff ocn_grid="SOwISC12to30E3r4">4.48e-3</config_implicit_top_drag_coeff>
 <config_loglaw_bottom_roughness>1.0e-3</config_loglaw_bottom_roughness>
 <config_loglaw_layer_depth_max>10.0</config_loglaw_layer_depth_max>
 <config_loglaw_bottom_drag_min>2.5e-3</config_loglaw_bottom_drag_min>
@@ -599,6 +614,7 @@
 <config_btr_dt ocn_grid="FRISwISC01to60E3r1">'0000_00:00:01.25'</config_btr_dt>
 <config_btr_dt ocn_grid="RRSwISC6to18E3r5">'0000_00:00:05'</config_btr_dt>
 <config_btr_dt ocn_grid="SOwISC12to30E3r3">'0000_00:00:15'</config_btr_dt>
+<config_btr_dt ocn_grid="SOwISC12to30E3r4">'0000_00:00:15'</config_btr_dt>
 <config_n_btr_cor_iter>2</config_n_btr_cor_iter>
 <config_vel_correction>.true.</config_vel_correction>
 <config_btr_subcycle_loop_factor>2</config_btr_subcycle_loop_factor>
@@ -648,6 +664,7 @@
 <config_check_ssh_consistency ocn_grid="FRISwISC01to60E3r1">.false.</config_check_ssh_consistency>
 <config_check_ssh_consistency ocn_grid="RRSwISC6to18E3r5">.false.</config_check_ssh_consistency>
 <config_check_ssh_consistency ocn_grid="SOwISC12to30E3r3">.false.</config_check_ssh_consistency>
+<config_check_ssh_consistency ocn_grid="SOwISC12to30E3r4">.false.</config_check_ssh_consistency>
 <config_filter_btr_mode>.false.</config_filter_btr_mode>
 <config_prescribe_velocity>.false.</config_prescribe_velocity>
 <config_prescribe_thickness>.false.</config_prescribe_thickness>
@@ -1143,6 +1160,7 @@
 <!-- AM_eddyProductVariables -->
 <config_AM_eddyProductVariables_enable>.false.</config_AM_eddyProductVariables_enable>
 <config_AM_eddyProductVariables_enable ocn_grid="SOwISC12to30E3r3">.true.</config_AM_eddyProductVariables_enable>
+<config_AM_eddyProductVariables_enable ocn_grid="SOwISC12to30E3r4">.true.</config_AM_eddyProductVariables_enable>
 <config_AM_eddyProductVariables_enable ocn_grid="RRSwISC6to18E3r5">.true.</config_AM_eddyProductVariables_enable>
 <config_AM_eddyProductVariables_compute_interval>'0000-00-00_01:00:00'</config_AM_eddyProductVariables_compute_interval>
 <config_AM_eddyProductVariables_output_stream>'eddyProductVariablesOutput'</config_AM_eddyProductVariables_output_stream>
@@ -1177,6 +1195,7 @@
 <config_AM_mocStreamfunction_enable ocn_grid="FRISwISC01to60E3r1">.true.</config_AM_mocStreamfunction_enable>
 <config_AM_mocStreamfunction_enable ocn_grid="RRSwISC6to18E3r5">.true.</config_AM_mocStreamfunction_enable>
 <config_AM_mocStreamfunction_enable ocn_grid="SOwISC12to30E3r3">.true.</config_AM_mocStreamfunction_enable>
+<config_AM_mocStreamfunction_enable ocn_grid="SOwISC12to30E3r4">.true.</config_AM_mocStreamfunction_enable>
 <config_AM_mocStreamfunction_compute_interval>'0000-00-00_01:00:00'</config_AM_mocStreamfunction_compute_interval>
 <config_AM_mocStreamfunction_output_stream>'mocStreamfunctionOutput'</config_AM_mocStreamfunction_output_stream>
 <config_AM_mocStreamfunction_compute_on_startup>.true.</config_AM_mocStreamfunction_compute_on_startup>
@@ -1257,12 +1276,15 @@
 <!-- AM_conservationCheck -->
 <config_AM_conservationCheck_enable>.false.</config_AM_conservationCheck_enable>
 <config_AM_conservationCheck_enable ocn_grid="SOwISC12to30E3r3">.true.</config_AM_conservationCheck_enable>
+<config_AM_conservationCheck_enable ocn_grid="SOwISC12to30E3r4">.true.</config_AM_conservationCheck_enable>
 <config_AM_conservationCheck_compute_interval>'dt'</config_AM_conservationCheck_compute_interval>
 <config_AM_conservationCheck_output_stream>'conservationCheckOutput'</config_AM_conservationCheck_output_stream>
 <config_AM_conservationCheck_compute_on_startup>.false.</config_AM_conservationCheck_compute_on_startup>
 <config_AM_conservationCheck_compute_on_startup ocn_grid="SOwISC12to30E3r3">.true.</config_AM_conservationCheck_compute_on_startup>
+<config_AM_conservationCheck_compute_on_startup ocn_grid="SOwISC12to30E3r4">.true.</config_AM_conservationCheck_compute_on_startup>
 <config_AM_conservationCheck_write_on_startup>.false.</config_AM_conservationCheck_write_on_startup>
 <config_AM_conservationCheck_write_on_startup ocn_grid="SOwISC12to30E3r3">.true.</config_AM_conservationCheck_write_on_startup>
+<config_AM_conservationCheck_write_on_startup ocn_grid="SOwISC12to30E3r4">.true.</config_AM_conservationCheck_write_on_startup>
 <config_AM_conservationCheck_write_to_logfile>.true.</config_AM_conservationCheck_write_to_logfile>
 <config_AM_conservationCheck_restart_stream>'conservationCheckRestart'</config_AM_conservationCheck_restart_stream>
 
diff --git a/components/mpas-ocean/cime_config/buildnml b/components/mpas-ocean/cime_config/buildnml
index b030f3fd268c..34979d56b822 100755
--- a/components/mpas-ocean/cime_config/buildnml
+++ b/components/mpas-ocean/cime_config/buildnml
@@ -419,6 +419,18 @@ def buildnml(case, caseroot, compname):
         if ocn_ismf == 'data':
             data_ismf_file = 'prescribed_ismf_paolo2023.SOwISC12to30E3r3.20241017.nc'
 
+    elif ocn_grid == 'SOwISC12to30E3r4':
+        decomp_date = '20250121'
+        decomp_prefix = 'partitions/mpas-o.graph.info.'
+        restoring_file = 'sss.WOA23_monthlyClimatology.SOwISC12to30E3r4.20250121.nc'
+        analysis_mask_file = 'SOwISC12to30E3r4_mocBasinsAndTransects20210623.nc'
+        ic_date = '20250121'
+        ic_prefix = 'mpaso.SOwISC12to30E3r4'
+        if ocn_ic_mode == 'spunup':
+            logger.warning("WARNING: The specified compset is requesting ocean ICs spunup from a G-case")
+            logger.warning("         But no file available for this grid.")
+        if ocn_ismf == 'data':
+            data_ismf_file = 'prescribed_ismf_paolo2023.SOwISC12to30E3r4.20250121.nc'
 
     #--------------------------------------------------------------------
     # Set OCN_FORCING = datm_forced_restoring if restoring file is available
diff --git a/components/mpas-seaice/bld/namelist_files/namelist_defaults_mpassi.xml b/components/mpas-seaice/bld/namelist_files/namelist_defaults_mpassi.xml
index 4ce60e42bcbe..898714242c8d 100644
--- a/components/mpas-seaice/bld/namelist_files/namelist_defaults_mpassi.xml
+++ b/components/mpas-seaice/bld/namelist_files/namelist_defaults_mpassi.xml
@@ -32,6 +32,7 @@
 <config_dt ice_grid="FRISwISC01to60E3r1">60.0</config_dt>
 <config_dt ice_grid="RRSwISC6to18E3r5">900.0</config_dt>
 <config_dt ice_grid="SOwISC12to30E3r3">1800.0</config_dt>
+<config_dt ice_grid="SOwISC12to30E3r4">1800.0</config_dt>
 <config_calendar_type>'noleap'</config_calendar_type>
 <config_start_time>'2000-01-01_00:00:00'</config_start_time>
 <config_stop_time>'none'</config_stop_time>
@@ -89,6 +90,7 @@
 <config_initial_latitude_north ice_grid="FRISwISC02to60E3r1">85.0</config_initial_latitude_north>
 <config_initial_latitude_north ice_grid="FRISwISC01to60E3r1">85.0</config_initial_latitude_north>
 <config_initial_latitude_north ice_grid="SOwISC12to30E3r3">85.0</config_initial_latitude_north>
+<config_initial_latitude_north ice_grid="SOwISC12to30E3r4">85.0</config_initial_latitude_north>
 <config_initial_latitude_north ice_grid="ARRM10to60E2r1">75.0</config_initial_latitude_north>
 <config_initial_latitude_north ice_grid="oRRS30to10v3wLI">85.0</config_initial_latitude_north>
 <config_initial_latitude_north ice_grid="oRRS18to6v3">85.0</config_initial_latitude_north>
@@ -105,6 +107,7 @@
 <config_initial_latitude_south ice_grid="FRISwISC02to60E3r1">-85.0</config_initial_latitude_south>
 <config_initial_latitude_south ice_grid="FRISwISC01to60E3r1">-85.0</config_initial_latitude_south>
 <config_initial_latitude_south ice_grid="SOwISC12to30E3r3">-85.0</config_initial_latitude_south>
+<config_initial_latitude_south ice_grid="SOwISC12to30E3r4">-85.0</config_initial_latitude_south>
 <config_initial_latitude_south ice_grid="ARRM10to60E2r1">-85.0</config_initial_latitude_south>
 <config_initial_latitude_south ice_grid="oRRS30to10v3wLI">-85.0</config_initial_latitude_south>
 <config_initial_latitude_south ice_grid="oRRS18to6v3">-85.0</config_initial_latitude_south>
@@ -174,6 +177,7 @@
 <config_dynamics_subcycle_number ice_grid="FRISwISC01to60E3r1">1</config_dynamics_subcycle_number>
 <config_dynamics_subcycle_number ice_grid="RRSwISC6to18E3r5">2</config_dynamics_subcycle_number>
 <config_dynamics_subcycle_number ice_grid="SOwISC12to30E3r3">1</config_dynamics_subcycle_number>
+<config_dynamics_subcycle_number ice_grid="SOwISC12to30E3r4">1</config_dynamics_subcycle_number>
 <config_rotate_cartesian_grid>true</config_rotate_cartesian_grid>
 <config_include_metric_terms>true</config_include_metric_terms>
 <config_elastic_subcycle_number>120</config_elastic_subcycle_number>
diff --git a/components/mpas-seaice/cime_config/buildnml b/components/mpas-seaice/cime_config/buildnml
index 5df71d69b1a8..fe5361c7bd34 100755
--- a/components/mpas-seaice/cime_config/buildnml
+++ b/components/mpas-seaice/cime_config/buildnml
@@ -340,6 +340,16 @@ def buildnml(case, caseroot, compname):
             grid_date = '20240829'
             grid_prefix = 'mpassi.SOwISC12to30E3r3.rstFromG-chrysalis'
 
+    elif ice_grid == 'SOwISC12to30E3r4':
+        grid_date = '20250121'
+        grid_prefix = 'mpassi.SOwISC12to30E3r4'
+        decomp_date = '20250121'
+        decomp_prefix = 'partitions/mpas-seaice.graph.info.'
+        data_iceberg_file = 'Iceberg_Climatology_Merino.SOwISC12to30E3r4.20250121.nc'
+        if ice_ic_mode == 'spunup':
+            logger.warning("WARNING: The specified compset is requesting seaice ICs spunup from a G-case")
+            logger.warning("         But no file available for this grid.")
+
     elif ice_grid == 'ICOS10':
         grid_date = '211015'
         grid_prefix = 'seaice.ICOS10'