diff --git a/parm/soca/obs/config/adt_rads_all.yaml b/parm/soca/obs/config/adt_rads_all.yaml
index 74469902..e0839cac 100644
--- a/parm/soca/obs/config/adt_rads_all.yaml
+++ b/parm/soca/obs/config/adt_rads_all.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}adt_rads_all.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}adt_rads_all.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/adt_rads_all.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/adt_rads_all.${PDY}${cyc}.nc
   simulated variables: [absoluteDynamicTopography]
   io pool:
     max pool size: 1
diff --git a/parm/soca/obs/config/icec_amsr2_north.yaml b/parm/soca/obs/config/icec_amsr2_north.yaml
index 6365e7fb..ae77e639 100644
--- a/parm/soca/obs/config/icec_amsr2_north.yaml
+++ b/parm/soca/obs/config/icec_amsr2_north.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}icec_amsr2_north.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}icec_amsr2_north.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/icec_amsr2_north.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/icec_amsr2_north.${PDY}${cyc}.nc
   simulated variables: [seaIceFraction]
   io pool:
     max pool size: 1
diff --git a/parm/soca/obs/config/icec_amsr2_south.yaml b/parm/soca/obs/config/icec_amsr2_south.yaml
index 977644ef..b640a16d 100644
--- a/parm/soca/obs/config/icec_amsr2_south.yaml
+++ b/parm/soca/obs/config/icec_amsr2_south.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}icec_amsr2_south.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}icec_amsr2_south.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/icec_amsr2_south.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/icec_amsr2_south.${PDY}${cyc}.nc
   simulated variables: [seaIceFraction]
   io pool:
     max pool size: 1
diff --git a/parm/soca/obs/config/insitu_profile_argo.yaml b/parm/soca/obs/config/insitu_profile_argo.yaml
index 9b054931..2359d50f 100644
--- a/parm/soca/obs/config/insitu_profile_argo.yaml
+++ b/parm/soca/obs/config/insitu_profile_argo.yaml
@@ -3,7 +3,7 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_argo.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_argo.${PDY}${cyc}.nc
     obsgrouping:
       group variables: [latitude, longitude, dateTime]
       sort variable: depth
@@ -12,7 +12,7 @@ obs space:
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/insitu_profile_argo.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/insitu_profile_argo.${PDY}${cyc}.nc
   simulated variables: [waterTemperature, salinity]
   observed variables: [waterTemperature, salinity]
   derived variables: [waterPressure]
diff --git a/parm/soca/obs/config/insitu_profile_bathy.yaml b/parm/soca/obs/config/insitu_profile_bathy.yaml
index 8742f44f..6d298712 100644
--- a/parm/soca/obs/config/insitu_profile_bathy.yaml
+++ b/parm/soca/obs/config/insitu_profile_bathy.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_bathy.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_bathy.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/insitu_profile_bathy.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/insitu_profile_bathy.${PDY}${cyc}.nc
   simulated variables: [waterTemperature]
   io pool:
     max pool size: 1
diff --git a/parm/soca/obs/config/insitu_profile_dbuoy.yaml b/parm/soca/obs/config/insitu_profile_dbuoy.yaml
index 5f81902e..be531f50 100644
--- a/parm/soca/obs/config/insitu_profile_dbuoy.yaml
+++ b/parm/soca/obs/config/insitu_profile_dbuoy.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_dbuoy.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_dbuoy.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/insitu_profile_dbuoy.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/insitu_profile_dbuoy.${PDY}${cyc}.nc
   simulated variables: [waterTemperature]
   observed variables: [waterTemperature]
   io pool:
diff --git a/parm/soca/obs/config/insitu_profile_dbuoyb.yaml b/parm/soca/obs/config/insitu_profile_dbuoyb.yaml
index 29052312..14d3a49d 100644
--- a/parm/soca/obs/config/insitu_profile_dbuoyb.yaml
+++ b/parm/soca/obs/config/insitu_profile_dbuoyb.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_dbuoyb.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_dbuoyb.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/insitu_profile_dbuoyb.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/insitu_profile_dbuoyb.${PDY}${cyc}.nc
   simulated variables: [waterTemperature]
   observed variables: [waterTemperature]
   io pool:
diff --git a/parm/soca/obs/config/insitu_profile_glider.yaml b/parm/soca/obs/config/insitu_profile_glider.yaml
index 17242b58..eba2ff04 100644
--- a/parm/soca/obs/config/insitu_profile_glider.yaml
+++ b/parm/soca/obs/config/insitu_profile_glider.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_glider.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_glider.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/insitu_profile_glider.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/insitu_profile_glider.${PDY}${cyc}.nc
   simulated variables: [waterTemperature]
   observed variables: [waterTemperature]
   io pool:
diff --git a/parm/soca/obs/config/insitu_profile_marinemammal.yaml b/parm/soca/obs/config/insitu_profile_marinemammal.yaml
index 682b02f0..c86dfc97 100644
--- a/parm/soca/obs/config/insitu_profile_marinemammal.yaml
+++ b/parm/soca/obs/config/insitu_profile_marinemammal.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_marinemammal.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_marinemammal.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/insitu_profile_marinemammal.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/insitu_profile_marinemammal.${PDY}${cyc}.nc
   simulated variables: [waterTemperature]
   observed variables: [waterTemperature]
   io pool:
diff --git a/parm/soca/obs/config/insitu_profile_mbuoy.yaml b/parm/soca/obs/config/insitu_profile_mbuoy.yaml
index c2b2ca61..39637277 100644
--- a/parm/soca/obs/config/insitu_profile_mbuoy.yaml
+++ b/parm/soca/obs/config/insitu_profile_mbuoy.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_mbuoy.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_mbuoy.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/insitu_profile_mbuoy.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/insitu_profile_mbuoy.${PDY}${cyc}.nc
   simulated variables: [waterTemperature]
   observed variables: [waterTemperature]
   io pool:
diff --git a/parm/soca/obs/config/insitu_profile_mbuoyb.yaml b/parm/soca/obs/config/insitu_profile_mbuoyb.yaml
index f8ad55e6..06baa288 100644
--- a/parm/soca/obs/config/insitu_profile_mbuoyb.yaml
+++ b/parm/soca/obs/config/insitu_profile_mbuoyb.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_mbuoyb.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_mbuoyb.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/insitu_profile_mbuoyb.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/insitu_profile_mbuoyb.${PDY}${cyc}.nc
   simulated variables: [waterTemperature]
   observed variables: [waterTemperature]
   io pool:
diff --git a/parm/soca/obs/config/insitu_profile_tesac.yaml b/parm/soca/obs/config/insitu_profile_tesac.yaml
index bc8342dc..00c6a6ad 100644
--- a/parm/soca/obs/config/insitu_profile_tesac.yaml
+++ b/parm/soca/obs/config/insitu_profile_tesac.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_tesac.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_tesac.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/insitu_profile_tesac.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/insitu_profile_tesac.${PDY}${cyc}.nc
   simulated variables: [waterTemperature]
   observed variables: [waterTemperature]
   io pool:
diff --git a/parm/soca/obs/config/insitu_profile_tesac_salinity.yaml b/parm/soca/obs/config/insitu_profile_tesac_salinity.yaml
index 9190e46e..341c8533 100644
--- a/parm/soca/obs/config/insitu_profile_tesac_salinity.yaml
+++ b/parm/soca/obs/config/insitu_profile_tesac_salinity.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_tesac.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_tesac.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/insitu_profile_tesac_salinity.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/insitu_profile_tesac_salinity.${PDY}${cyc}.nc
   simulated variables: [salinity]
   observed variables: [salinity]
   io pool:
diff --git a/parm/soca/obs/config/insitu_profile_xbtctd.yaml b/parm/soca/obs/config/insitu_profile_xbtctd.yaml
index a868fc8c..b5f5c77a 100644
--- a/parm/soca/obs/config/insitu_profile_xbtctd.yaml
+++ b/parm/soca/obs/config/insitu_profile_xbtctd.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_xbtctd.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_profile_xbtctd.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/insitu_profile_xbtctd.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/insitu_profile_xbtctd.${PDY}${cyc}.nc
   simulated variables: [waterTemperature]
   observed variables: [waterTemperature]
   io pool:
diff --git a/parm/soca/obs/config/insitu_surface_altkob.yaml b/parm/soca/obs/config/insitu_surface_altkob.yaml
index d39bf59b..97aa5f75 100644
--- a/parm/soca/obs/config/insitu_surface_altkob.yaml
+++ b/parm/soca/obs/config/insitu_surface_altkob.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_surface_altkob.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_surface_altkob.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/insitu_surface_altkob.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/insitu_surface_altkob.${PDY}${cyc}.nc
   simulated variables: [seaSurfaceTemperature]
   io pool:
     max pool size: 1
diff --git a/parm/soca/obs/config/insitu_surface_trkob.yaml b/parm/soca/obs/config/insitu_surface_trkob.yaml
index e3523022..3dc373d9 100644
--- a/parm/soca/obs/config/insitu_surface_trkob.yaml
+++ b/parm/soca/obs/config/insitu_surface_trkob.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_surface_trkob.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_surface_trkob.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/insitu_surface_trkob.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/insitu_surface_trkob.${PDY}${cyc}.nc
   simulated variables: [seaSurfaceTemperature]
   io pool:
     max pool size: 1
diff --git a/parm/soca/obs/config/insitu_surface_trkob_salinity.yaml b/parm/soca/obs/config/insitu_surface_trkob_salinity.yaml
index f32e6658..be32c8c0 100644
--- a/parm/soca/obs/config/insitu_surface_trkob_salinity.yaml
+++ b/parm/soca/obs/config/insitu_surface_trkob_salinity.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_surface_trkob.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}insitu_surface_trkob.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/insitu_surface_trkob_salinity.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/insitu_surface_trkob_salinity.${PDY}${cyc}.nc
   simulated variables: [seaSurfaceSalinity]
 get values:
   time interpolation: linear
diff --git a/parm/soca/obs/config/sst_abi_g16_l3c.yaml b/parm/soca/obs/config/sst_abi_g16_l3c.yaml
index b9d99984..290faaa8 100644
--- a/parm/soca/obs/config/sst_abi_g16_l3c.yaml
+++ b/parm/soca/obs/config/sst_abi_g16_l3c.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}sst_abi_g16_l3c.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}sst_abi_g16_l3c.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/sst_abi_g16_l3c.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/sst_abi_g16_l3c.${PDY}${cyc}.nc
   simulated variables: [seaSurfaceTemperature]
   io pool:
     max pool size: 1
diff --git a/parm/soca/obs/config/sst_abi_g17_l3c.yaml b/parm/soca/obs/config/sst_abi_g17_l3c.yaml
index a7ada577..ddcaa93a 100644
--- a/parm/soca/obs/config/sst_abi_g17_l3c.yaml
+++ b/parm/soca/obs/config/sst_abi_g17_l3c.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}sst_abi_g17_l3c.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}sst_abi_g17_l3c.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/sst_abi_g17_l3c.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/sst_abi_g17_l3c.${PDY}${cyc}.nc
   simulated variables: [seaSurfaceTemperature]
   io pool:
     max pool size: 1
diff --git a/parm/soca/obs/config/sst_ahi_h08_l3c.yaml b/parm/soca/obs/config/sst_ahi_h08_l3c.yaml
index ed0efd72..1afbe4a3 100644
--- a/parm/soca/obs/config/sst_ahi_h08_l3c.yaml
+++ b/parm/soca/obs/config/sst_ahi_h08_l3c.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}sst_ahi_h08_l3c.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}sst_ahi_h08_l3c.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/sst_ahi_h08_l3c.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/sst_ahi_h08_l3c.${PDY}${cyc}.nc
   simulated variables: [seaSurfaceTemperature]
   io pool:
     max pool size: 1
diff --git a/parm/soca/obs/config/sst_avhrr_ma_l3u.yaml b/parm/soca/obs/config/sst_avhrr_ma_l3u.yaml
index 73c04889..85316429 100644
--- a/parm/soca/obs/config/sst_avhrr_ma_l3u.yaml
+++ b/parm/soca/obs/config/sst_avhrr_ma_l3u.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}sst_avhrr_ma_l3u.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}sst_avhrr_ma_l3u.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/sst_avhrr_ma_l3u.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/sst_avhrr_ma_l3u.${PDY}${cyc}.nc
   simulated variables: [seaSurfaceTemperature]
   io pool:
     max pool size: 1
diff --git a/parm/soca/obs/config/sst_avhrr_mb_l3u.yaml b/parm/soca/obs/config/sst_avhrr_mb_l3u.yaml
index ccac3cc4..aa65bbca 100644
--- a/parm/soca/obs/config/sst_avhrr_mb_l3u.yaml
+++ b/parm/soca/obs/config/sst_avhrr_mb_l3u.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}sst_avhrr_mb_l3u.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}sst_avhrr_mb_l3u.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/sst_avhrr_mb_l3u.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/sst_avhrr_mb_l3u.${PDY}${cyc}.nc
   simulated variables: [seaSurfaceTemperature]
   io pool:
     max pool size: 1
diff --git a/parm/soca/obs/config/sst_avhrr_mc_l3u.yaml b/parm/soca/obs/config/sst_avhrr_mc_l3u.yaml
index 9c34bcd5..6afa214f 100644
--- a/parm/soca/obs/config/sst_avhrr_mc_l3u.yaml
+++ b/parm/soca/obs/config/sst_avhrr_mc_l3u.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}sst_avhrr_mc_l3u.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}sst_avhrr_mc_l3u.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/sst_avhrr_mc_l3u.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/sst_avhrr_mc_l3u.${PDY}${cyc}.nc
   simulated variables: [seaSurfaceTemperature]
   io pool:
     max pool size: 1
diff --git a/parm/soca/obs/config/sst_viirs_n20_l3u.yaml b/parm/soca/obs/config/sst_viirs_n20_l3u.yaml
index 04021235..9121a7e0 100644
--- a/parm/soca/obs/config/sst_viirs_n20_l3u.yaml
+++ b/parm/soca/obs/config/sst_viirs_n20_l3u.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}sst_viirs_n20_l3u.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}sst_viirs_n20_l3u.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/sst_viirs_n20_l3u.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/sst_viirs_n20_l3u.${PDY}${cyc}.nc
   simulated variables: [seaSurfaceTemperature]
   io pool:
     max pool size: 1
diff --git a/parm/soca/obs/config/sst_viirs_npp_l3u.yaml b/parm/soca/obs/config/sst_viirs_npp_l3u.yaml
index 6df13028..a21b52d5 100644
--- a/parm/soca/obs/config/sst_viirs_npp_l3u.yaml
+++ b/parm/soca/obs/config/sst_viirs_npp_l3u.yaml
@@ -3,11 +3,11 @@ obs space:
   obsdatain:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/obs/${OPREFIX}sst_viirs_npp_l3u.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/obs/${OPREFIX}sst_viirs_npp_l3u.${PDY}${cyc}.nc
   obsdataout:
     engine:
       type: H5File
-      obsfile: !ENV ${DATA}/diags/sst_viirs_npp_l3u.${PDY}${cyc}.nc4
+      obsfile: !ENV ${DATA}/diags/sst_viirs_npp_l3u.${PDY}${cyc}.nc
   simulated variables: [seaSurfaceTemperature]
   io pool:
     max pool size: 1
diff --git a/scripts/exgdas_global_marine_analysis_prep.py b/scripts/exgdas_global_marine_analysis_prep.py
index dba49186..721a2242 100755
--- a/scripts/exgdas_global_marine_analysis_prep.py
+++ b/scripts/exgdas_global_marine_analysis_prep.py
@@ -142,7 +142,7 @@ def parse_obs_list_file():
 # get the list of observations
 obs_files = []
 for ob in stage_cfg['observations']['observers']:
-    obs_files.append(f"{RUN}.t{cyc}z.{ob['obs space']['name'].lower()}.{PDY}{cyc}.nc4")
+    obs_files.append(f"{RUN}.t{cyc}z.{ob['obs space']['name'].lower()}.{PDY}{cyc}.nc")
 obs_list = []
 
 # copy obs from COM_OBS to DATA/obs
diff --git a/ush/soca/prep_ocean_obs.py b/ush/soca/prep_ocean_obs.py
index 1d6b55e8..3a768e7e 100644
--- a/ush/soca/prep_ocean_obs.py
+++ b/ush/soca/prep_ocean_obs.py
@@ -144,7 +144,7 @@ def initialize(self):
                         obsprep_space['input files'] = input_files
                         obsprep_space['window begin'] = self.window_begin
                         obsprep_space['window end'] = self.window_end
-                        ioda_filename = f"{RUN}.t{cyc:02d}z.{obs_space_name}.{cdatestr}.nc4"
+                        ioda_filename = f"{RUN}.t{cyc:02d}z.{obs_space_name}.{cdatestr}.nc"
                         obsprep_space['output file'] = ioda_filename
 
                         # set up the config file for conversion to IODA for bufr and