diff --git a/.gitmodules b/.gitmodules
index 2725566e..6cd53250 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -9,7 +9,7 @@
 [submodule "models/parflow_pdaf"]
 	path = models/parflow_pdaf
 	url = https://github.com/HPSCTerrSys/parflow
-	branch = v3.14.1-pdaf
+	branch = v3.15.0-pdaf
 [submodule "models/pdaf"]
 	path = models/pdaf
 	url = https://github.com/HPSCTerrSys/pdaf.git
@@ -17,11 +17,11 @@
 [submodule "models/eCLM"]
 	path = models/eCLM
 	url = https://github.com/HPSCTerrSys/eCLM.git
-	branch = master-parallel-build
+	branch = dev-iconeclm-exchfix
 [submodule "models/oasis3-mct"]
         path = models/oasis3-mct
         url = https://icg4geo.icg.kfa-juelich.de/ExternalReposPublic/oasis3-mct
-	branch = v5.0_patched
+	branch = tsmp-patches-v0.2
 [submodule "models/CLM3.5"]
 	path = models/CLM3.5
 	url = https://github.com/HPSCTerrSys/CLM3.5.git
diff --git a/CMakeLists.txt b/CMakeLists.txt
index c6ec4ab3..5b8b9777 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -60,7 +60,7 @@ if (${ICON} OR ${ICONGPU})
     set(ICON_SRC "${CMAKE_SOURCE_DIR}/models/icon")
   endif()
   include(BuildICON)
-  list(APPEND COMPONENT_MODELS "ICON")
+  list(APPEND COMPONENT_MODELS ${ICON_ID})
   if ("${MODEL_ID}" STREQUAL "")
       set(MODEL_ID "${ICON_ID}")
   else()
diff --git a/build_tsmp2.sh b/build_tsmp2.sh
index 5ae47fba..3698f767 100755
--- a/build_tsmp2.sh
+++ b/build_tsmp2.sh
@@ -123,14 +123,14 @@ while [[ "$#" -gt 0 ]]; do
     -q|--quiet) quiet=y;;
     -v|--verbose) verbose_makefile=y;;
     --version) echo "$0 version 0.2.0"; exit 0;;
-    --icon|icon) icon=y iconCPU=y iconCMakeModelID="ICON";;
+    icon) icon=y iconCPU=y iconCMakeModelID="ICON";;
     icongpu) icon=y iconGPU=y iconCMakeModelID="ICONGPU";;
-    --eclm|eclm) eclm=y;;
-    --parflow|parflow) parflow=y parflowCPU=y parflowCMakeModelID="ParFlow";;
-    --parflowgpu|parflowgpu) parflow=y parflowGPU=y parflowCMakeModelID="ParFlowGPU";;
-    --pdaf|pdaf) pdaf=y;;
-    --cosmo|cosmo) cosmo=y;;
-    --clm35|--clm3.5|clm3.5) clm35=y;;
+    eclm) eclm=y;;
+    parflow) parflow=y parflowCPU=y parflowCMakeModelID="ParFlow";;
+    parflowgpu) parflow=y parflowGPU=y parflowCMakeModelID="ParFlowGPU";;
+    pdaf) pdaf=y;;
+    cosmo) cosmo=y;;
+    clm3.5) clm35=y;;
     --no_update) update_compsrc=n;;
     --clean_first) clean_first=y;;
     --icon_src) icon_src="$2"; shift ;;
@@ -234,9 +234,11 @@ fi
 if [[ -n "${env}" ]]; then
   message "Sourcing environment..."
 
-  # TODO: Fix this GPU thing on another PR
+  # TODO: Fix this messy GPU env parameterization on another PR
   if [[ "$parflowGPU" == "y" ]];then
     source "${env}" --parflowgpu
+  elif [[ "$iconGPU" == "y" ]];then
+    source "${env}" --icongpu
   else
     source "${env}"
   fi
diff --git a/cmake/BuildICON.cmake b/cmake/BuildICON.cmake
index adea7ba3..c635a6f6 100644
--- a/cmake/BuildICON.cmake
+++ b/cmake/BuildICON.cmake
@@ -112,7 +112,9 @@ endif()
 
 # GPU-specific options
 if(${ICONGPU})
-  list(APPEND ICON_LIBS "-c++libs -nvmalloc -cuda")
+  if(CMAKE_Fortran_COMPILER_ID STREQUAL "NVHPC")
+    list(APPEND ICON_LIBS "-c++libs -nvmalloc -cuda")
+  endif()
   list(APPEND EXTRA_CONFIG_ARGS --enable-gpu=openacc --enable-mpi-gpu --enable-cuda-graphs --enable-pgi-inlib)
 else()
   list(APPEND EXTRA_CONFIG_ARGS --enable-openmp)
diff --git a/cmake/BuildOASIS3MCT.cmake b/cmake/BuildOASIS3MCT.cmake
index 0dcbfabd..eee469ee 100644
--- a/cmake/BuildOASIS3MCT.cmake
+++ b/cmake/BuildOASIS3MCT.cmake
@@ -13,6 +13,15 @@ else()
   message(WARNING "CMAKE_BUILD_TYPE='${CMAKE_BUILD_TYPE}' is not supported by OASIS3-MCT")
 endif()
 
+set(CPPDEF_EXTRAS "")
+if(${PDAF})
+  string(APPEND CPPDEF_EXTRAS " -DUSE_PDAF")
+endif()
+if(CMAKE_Fortran_COMPILER_ID STREQUAL "NVHPC")
+  # NVHPC doesn't support quad precision. https://forums.developer.nvidia.com/t/real-16-implementation/129969
+  string(APPEND CPPDEF_EXTRAS " -D__NO_16BYTE_REALS")
+endif()
+
 set(OASIS_BLD_DIR ${CMAKE_CURRENT_BINARY_DIR}/OASIS3_MCT/bld)
 set(OASIS_MAKE_INC ${OASIS_BLD_DIR}/make.inc)
 set(OASIS_INSTALL_PREFIX ${CMAKE_INSTALL_PREFIX}/OASIS3-MCT)
@@ -35,15 +44,13 @@ file(APPEND  ${OASIS_MAKE_INC} "AR              = ar\n")
 file(APPEND  ${OASIS_MAKE_INC} "ARFLAGS         = -ruv\n")
 file(APPEND  ${OASIS_MAKE_INC} "DYNOPT          = -fPIC\n")
 file(APPEND  ${OASIS_MAKE_INC} "LDDYNOPT        = -shared\n")
-if(${PDAF})
-  file(APPEND  ${OASIS_MAKE_INC} "CPPDEF          = -Duse_netCDF -Duse_comm_$(CHAN) -D__VERBOSE  -DTREAT_OVERLAY -DUSE_PDAF\n")
-else()
-  file(APPEND  ${OASIS_MAKE_INC} "CPPDEF          = -Duse_netCDF -Duse_comm_$(CHAN) -D__VERBOSE  -DTREAT_OVERLAY\n")
-endif()
+file(APPEND  ${OASIS_MAKE_INC} "CPPDEF          = -Duse_netCDF -Duse_comm_$(CHAN) -D__VERBOSE -DTREAT_OVERLAY ${CPPDEF_EXTRAS}\n")
 if(CMAKE_Fortran_COMPILER_ID STREQUAL "GNU")
   file(APPEND  ${OASIS_MAKE_INC} "FCBASEFLAGS     = ${OPTIM} -I. -ffree-line-length-none -fallow-argument-mismatch ${OpenMP_Fortran_FLAGS}\n")
 elseif(CMAKE_Fortran_COMPILER_ID STREQUAL "Intel" OR CMAKE_Fortran_COMPILER_ID STREQUAL "IntelLLVM")
   file(APPEND  ${OASIS_MAKE_INC} "FCBASEFLAGS     = ${OPTIM} -I. -xCORE-AVX2 -assume byterecl -mt_mpi ${OpenMP_Fortran_FLAGS}\n")
+elseif(CMAKE_Fortran_COMPILER_ID STREQUAL "NVHPC")
+  file(APPEND  ${OASIS_MAKE_INC} "FCBASEFLAGS     = ${OPTIM} -I. -fPIC ${OpenMP_Fortran_FLAGS}\n")
 else()
   message(FATAL_ERROR "Fortran compiler '${CMAKE_Fortran_COMPILER_ID}' is not supported.")
 endif()
@@ -67,7 +74,7 @@ ExternalProject_Add(OASIS3_MCT
   PREFIX            OASIS3_MCT
   SOURCE_DIR        ${OASIS_SRC}
   BUILD_IN_SOURCE   FALSE
-  CONFIGURE_COMMAND ""
+  CONFIGURE_COMMAND make -f ${OASIS_SRC}/util/make_dir/TopMakefileOasis3 realclean -C ${OASIS_BLD_DIR}
   BUILD_COMMAND     make -j ${PARALLEL_JOBS} -f ${OASIS_SRC}/util/make_dir/TopMakefileOasis3 static-libs -C ${OASIS_BLD_DIR}
   INSTALL_COMMAND   ""
 )
diff --git a/cmake/BuildPDAF.cmake b/cmake/BuildPDAF.cmake
index b89685c9..2c796e5b 100644
--- a/cmake/BuildPDAF.cmake
+++ b/cmake/BuildPDAF.cmake
@@ -141,6 +141,24 @@ elseif (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
   list(APPEND PDAF_FOPT "-fallow-argument-mismatch")
   list(APPEND PDAF_FOPT "-fcommon")
 
+elseif (CMAKE_CXX_COMPILER_ID STREQUAL "NVHPC")
+
+  # using NVIDIA HPC SDK
+  if (CMAKE_BUILD_TYPE STREQUAL "RELEASE")
+    list(APPEND PDAF_FOPT "-O2")
+  elseif (CMAKE_BUILD_TYPE STREQUAL "DEBUG")
+    list(APPEND PDAF_FOPT "-O0")
+    list(APPEND PDAF_FOPT "-g")
+    list(APPEND PDAF_FOPT "-traceback")
+  else()
+    message(FATAL_ERROR "Unsupported CMAKE_BUILD_TYPE: ${CMAKE_BUILD_TYPE}")
+  endif()
+
+  list(APPEND PDAF_FOPT "-Msave")
+  list(APPEND PDAF_FOPT "-Mlarge_arrays")
+  list(APPEND PDAF_FOPT "-Mbyteswapio")
+  list(APPEND PDAF_FOPT "-Mfreeform")
+
 else()
   message(FATAL_ERROR "Unsupported CMAKE_CXX_COMPILER_ID: ${CMAKE_CXX_COMPILER_ID}")
 endif()
@@ -189,6 +207,19 @@ elseif (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
   list(APPEND PDAF_COPT "-mcmodel=large")
   list(APPEND PDAF_COPT "-fcommon")
 
+elseif (CMAKE_CXX_COMPILER_ID STREQUAL "NVHPC")
+
+  # using NVIDIA HPC SDK
+  if (CMAKE_BUILD_TYPE STREQUAL "RELEASE")
+    list(APPEND PDAF_COPT "-O2")
+  elseif (CMAKE_BUILD_TYPE STREQUAL "DEBUG")
+    list(APPEND PDAF_COPT "-O0")
+    list(APPEND PDAF_COPT "-g")
+    list(APPEND PDAF_COPT "-traceback")
+  else()
+    message(FATAL_ERROR "Unsupported CMAKE_BUILD_TYPE: ${CMAKE_BUILD_TYPE}")
+  endif()
+
 else()
   message(FATAL_ERROR "Unsupported CMAKE_CXX_COMPILER_ID: ${CMAKE_CXX_COMPILER_ID}")
 endif()
@@ -207,6 +238,10 @@ elseif (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
 
   list(APPEND PDAF_DOUBLEPRECISION "-fdefault-real-8")
 
+elseif (CMAKE_CXX_COMPILER_ID STREQUAL "NVHPC")
+
+  list(APPEND PDAF_DOUBLEPRECISION "-r8")
+
 else()
   message(FATAL_ERROR "Unsupported CMAKE_CXX_COMPILER_ID: ${CMAKE_CXX_COMPILER_ID}")
 endif()
@@ -247,6 +282,10 @@ elseif (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
 
   list(APPEND PDAF_MODULEOPT "-J")
 
+elseif (CMAKE_CXX_COMPILER_ID STREQUAL "NVHPC")
+
+  list(APPEND PDAF_MODULEOPT "-module")
+
 else()
   message(FATAL_ERROR "Unsupported CMAKE_CXX_COMPILER_ID: ${CMAKE_CXX_COMPILER_ID}")
 endif()
diff --git a/cmake/BuildPDAFMODEL.cmake b/cmake/BuildPDAFMODEL.cmake
index 3e7608ae..cf715674 100644
--- a/cmake/BuildPDAFMODEL.cmake
+++ b/cmake/BuildPDAFMODEL.cmake
@@ -97,7 +97,10 @@ endif()
 
 # ParFlow libraries
 if(DEFINED PARFLOW_SRC)
-  list(APPEND PDAF_LIBS "-L${CMAKE_INSTALL_PREFIX}/lib -lpfsimulator -lamps -lpfkinsol -lgfortran -lcjson")
+  list(APPEND PDAF_LIBS "-L${CMAKE_INSTALL_PREFIX}/lib -lpfsimulator -lamps -lpfkinsol -lcjson")
+  if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+    list(APPEND PDAF_LIBS "-lgfortran")
+  endif()
   # GPU
   # list(APPEND PDAF_LIBS "-L${CMAKE_INSTALL_PREFIX}/rmm/lib -lstdc++ -lcudart -lrmm -lnvToolsExt")
 
@@ -117,6 +120,28 @@ if(DEFINED PARFLOW_SRC)
   # Unconditional loading of stdc++
   list(APPEND PDAF_LIBS "-lstdc++")
 
+  # GPU: libpfsimulator and libHYPRE (nvofbf toolchain) contain GPU objects
+  # requiring CUDA and Umpire libraries at final link of tsmp-pdaf.
+  if(${ParFlowGPU})
+    list(APPEND PDAF_LIBS "-lcudart")
+    # CUDA math libraries needed by GPU-enabled HYPRE (nvofbf toolchain)
+    list(APPEND PDAF_LIBS "-lcurand")
+    list(APPEND PDAF_LIBS "-lcublas")
+    list(APPEND PDAF_LIBS "-lcusparse")
+    # Umpire memory manager needed by libamps and libHYPRE (nvofbf toolchain)
+    find_library(UMPIRE_LIB NAMES umpire
+      HINTS
+        ${UMPIRE_ROOT}/lib
+        $ENV{UMPIRE_ROOT}/lib
+        $ENV{EBROOTUMPIRE}/lib
+    )
+    if(UMPIRE_LIB)
+      list(APPEND PDAF_LIBS "${UMPIRE_LIB}")
+    else()
+      message(WARNING "BuildPDAFMODEL: Umpire library not found. Set UMPIRE_ROOT or EBROOTUMPIRE if needed.")
+    endif()
+  endif()
+
   # SLURM library if enabled (typically on HPC-system)
   if(ENABLE_SLURM)
     list(APPEND PDAF_LIBS "-lslurm")
diff --git a/cmake/BuildParFlow.cmake b/cmake/BuildParFlow.cmake
index 4f5531d5..546480b9 100644
--- a/cmake/BuildParFlow.cmake
+++ b/cmake/BuildParFlow.cmake
@@ -53,6 +53,13 @@ if(CMAKE_C_COMPILER_ID STREQUAL "GNU")
     set(PF_FFLAGS "-ffree-line-length-none -ffixed-line-length-none")
 elseif(CMAKE_C_COMPILER_ID STREQUAL "Intel" OR CMAKE_C_COMPILER_ID STREQUAL "IntelLLVM")
     set(PF_CFLAGS "-Wall -Werror -Wno-unused-function -Wno-unused-variable")
+elseif(CMAKE_C_COMPILER_ID STREQUAL "NVHPC")
+    set(PF_CFLAGS "-Werror -Wno-unused --diag_suppress=unsigned_compare_with_negative,vla_treated_as_fixed_size_array,code_is_unreachable")
+    if(NOT ${ParFlowGPU})
+      message(FATAL_ERROR "BuildParFlow: NVHPC compiler detected but ParFlowGPU is not enabled. "
+        "NVHPC should for now  only be used for GPU-accelerated ParFlow builds (parflowGPU). "
+        "Use a GNU or Intel compiler for CPU-only ParFlow, or enable parflowGPU.")
+    endif()
 else()
   message(FATAL_ERROR "C compiler '${CMAKE_C_COMPILER_ID}' is not supported.")
 endif()
@@ -66,8 +73,14 @@ else()
 endif()
 
 # Enable Umpire if exists
-if (DEFINED ENV{UMPIRE_ROOT} AND NOT ${PDAF})
-  set(PF_UMPIRE_FLAG "-DUMPIRE_ROOT=$ENV{UMPIRE_ROOT}")
+if (DEFINED ENV{UMPIRE_ROOT} AND (NOT ${PDAF} OR ${ParFlowGPU}))
+  list(APPEND PF_UMPIRE_FLAG -DUMPIRE_ROOT=$ENV{UMPIRE_ROOT})
+  if(CMAKE_C_COMPILER_ID STREQUAL "NVHPC")
+    # Umpire leaks wrong OpenMP compile/linker flags when on NVHPC toolchain.
+    # See https://github.com/HPSCTerrSys/TSMP2/issues/148
+    list(APPEND PF_UMPIRE_FLAG -DBLT_OPENMP_COMPILE_FLAGS=-fopenmp
+                               -DBLT_OPENMP_LINK_FLAGS=-fopenmp)
+  endif()
 endif()
 
 # Enable SUNDIALS if exists
diff --git a/cmake/BuildeCLM.cmake b/cmake/BuildeCLM.cmake
index d11854af..941aa593 100644
--- a/cmake/BuildeCLM.cmake
+++ b/cmake/BuildeCLM.cmake
@@ -1,9 +1,9 @@
-if(${ICON} OR ${ParFlow} OR ${ParFlowGPU})
+if(${ICON} OR ${ICONGPU} OR ${ParFlow} OR ${ParFlowGPU})
     list(APPEND COUP_OAS_FLAGS -DUSE_OASIS=True)
     if(${ParFlow} OR ${ParFlowGPU})
         list(APPEND COUP_OAS_FLAGS  -DCOUP_OAS_PFL=True)
     endif()
-    if(${ICON})
+    if(${ICON} OR ${ICONGPU})
         list(APPEND COUP_OAS_FLAGS  -DCOUP_OAS_ICON=True)
     endif()
 else()
diff --git a/cmake/Utils.cmake b/cmake/Utils.cmake
index 15d11b93..adb37a2f 100644
--- a/cmake/Utils.cmake
+++ b/cmake/Utils.cmake
@@ -6,7 +6,7 @@ endif()
 # Count how many component models shoul be build, and if >=2 compile with OASIS
 function(check_build_oasis BUILD_OASIS)
    # Combine all options into a list
-   list(APPEND COMPONENT_MODELS ICON COSMO eCLM CLM3.5 ParFlow ParFlowGPU)
+   list(APPEND COMPONENT_MODELS ICON ICONGPU COSMO eCLM CLM3.5 ParFlow ParFlowGPU)
    # Count enabled models
    set(MODELCOUNT 0)
    foreach(comp_model IN LISTS COMPONENT_MODELS)
diff --git a/env/jsc.2023.intel.psmpi b/env/jsc.2023.intel.psmpi
deleted file mode 100644
index 3b9ac71e..00000000
--- a/env/jsc.2023.intel.psmpi
+++ /dev/null
@@ -1,34 +0,0 @@
-#!/usr/bin/env bash
-
-# Load modules
-module --force purge
-module use $OTHERSTAGES
-module load Stages/2023
-module load Intel/2022.1.0
-module load ParaStationMPI/5.7.0-1
-#
-module load Hypre/2.27.0-cpu
-module load Silo/4.11
-module load Tcl/8.6.12 
-#
-module load ecCodes/2.27.0 
-module load HDF5/1.12.2-serial 
-module load netCDF/4.9.0
-module load netCDF-Fortran/4.6.0
-module load PnetCDF/1.12.3
-module load cURL/7.83.0
-module load Szip/.2.1.1 
-module load Python/3.10.4
-module load NCO/5.1.3  
-module load CMake/3.23.1
-module load git/2.36.0-nodocs  
-
-module load pkgconf/.1.8.0
-
-module li
-
-# Set default compilers
-export CC=mpicc
-export FC=mpif90
-export CXX=mpicxx
-export MPI_HOME=$EBROOTPSMPI
diff --git a/env/jsc.2024.intel.psmpi b/env/jsc.2024.intel.psmpi
deleted file mode 100644
index 2908f650..00000000
--- a/env/jsc.2024.intel.psmpi
+++ /dev/null
@@ -1,44 +0,0 @@
-#!/usr/bin/env bash
-
-# Load modules
-module --force purge
-module use $OTHERSTAGES
-module load Stages/2024
-module load Intel/2023.2.1
-module load ParaStationMPI/5.9.2-1
-#module load IntelMPI/2021.10.0
-
-#
-module load Hypre/2.31.0-cpu
-module load Silo/4.11.1
-module load Tcl/8.6.13
-#
-module load ecCodes/2.31.0
-module load HDF5/1.14.2
-module load netCDF/4.9.2
-module load netCDF-Fortran/4.6.1
-module load PnetCDF/1.12.3
-module load cURL/8.0.1
-module load Szip/.2.1.1
-module load Python/3.11.3
-module load NCO/5.1.8
-module load CMake/3.26.3
-module load git/2.41.0-nodocs
-
-# Set default compilers
-export CC=mpicc
-export FC=mpif90
-export CXX=mpicxx
-export MPI_HOME=$EBROOTPSMPI
-
-# Display compiler settings
-module li
-echo "====================================== COMPILER SETTINGS ======================================"
-echo " Machine: ${SYSTEMNAME} on Stages/$STAGE"
-echo " MPI lib: $(mpichversion | head -n 1 | tr -d =)"
-echo "       C: $($CC --version | head -n 1)"
-echo "     C++: $($CXX --version | head -n 1)"
-echo " Fortran: $($FC --version | head -n 1)"
-echo "==============================================================================================="
-echo ""
-
diff --git a/env/jsc.2026.gnu.openmpi b/env/jsc.2026.gnu.openmpi
index c09c1713..b2b9ace1 100644
--- a/env/jsc.2026.gnu.openmpi
+++ b/env/jsc.2026.gnu.openmpi
@@ -32,7 +32,7 @@ module load PnetCDF
 module load Umpire
 module load SUNDIALS
 module load Tcl
-if [[ "$1" == "--parflowgpu" ]]; then
+if [[ "$1" == "--parflowgpu" || "$1" == "--icongpu" ]]; then
   module load CUDA
   module load UCX-settings/RC-CUDA
   module load Hypre/3.0.0
@@ -56,6 +56,10 @@ export CC=mpicc
 export FC=mpif90
 export CXX=mpicxx
 
+# OMPI_* variables affect OpenMPI backend compilers. They should be
+# unset so that the correct default backend compilers are selected.
+unset OMPI_CC OMPI_FC OMPI_CXX
+
 # Variables read by TSMP2 cmake scripts
 export MPI_HOME=$EBROOTOPENMPI
 export UMPIRE_ROOT=$EBROOTUMPIRE
@@ -70,7 +74,7 @@ echo "   MPI lib: OpenMPI v$EBVERSIONOPENMPI"
 echo "         C: $($CC --version | head -n 1)"
 echo "       C++: $($CXX --version | head -n 1)"
 echo "   Fortran: $($FC --version | head -n 1)"
-if [[ "$1" == "--parflowgpu" ]]; then
+if [[ "$1" == "--parflowgpu" || "$1" == "--icongpu" ]]; then
   echo "      nvcc: $(nvcc --version | tail -n 1 | cut -d" " -f2)"
   echo " CUDAARCHS: $CUDAARCHS"
 fi
diff --git a/env/jsc.2026.gnu.psmpi b/env/jsc.2026.gnu.psmpi
new file mode 100644
index 00000000..e80a5d8a
--- /dev/null
+++ b/env/jsc.2026.gnu.psmpi
@@ -0,0 +1,78 @@
+# ---------------------------------------------------------------------------------------
+# Loads GNU+OpenMPI build environment for TSMP2.
+# This environment is tailored for JURECA [1], JUWELS [2], and JUPITER [3] supercomputers.
+#
+# [1] https://apps.fz-juelich.de/jsc/software/jureca/index.xhtml
+# [2] https://apps.fz-juelich.de/jsc/software/juwels/index.xhtml
+# [3] https://apps.fz-juelich.de/jsc/hps/jupiter/index.html
+# Usage: source jsc.2026.gnu.openmpi
+# ---------------------------------------------------------------------------------------
+
+# Load Stages/2026
+module --force purge
+module use $OTHERSTAGES
+module load Stages/2026
+
+# Primary compiler toolchain
+module load GCC
+module load ParaStationMPI
+
+# Basic scripting and build tools
+module load Python
+module load CMake
+module load git
+
+# Storage libraries
+module load HDF5
+module load netCDF
+module load netCDF-Fortran
+module load PnetCDF
+
+# ParFlow additional libraries
+module load Umpire
+module load SUNDIALS
+module load Tcl
+if [[ "$1" == "--parflowgpu" ]]; then
+  module load CUDA
+  module load UCX-settings/RC-CUDA
+  module load Hypre/3.0.0
+
+  # TODO: Verify these values
+  if [[ $SYSTEMNAME == "jupiter" || $SYSTEMNAME == "jureca_gh" ]]; then
+    export CUDAARCHS="90"
+  else
+    export CUDAARCHS="80"
+  fi
+  export CMAKE_CUDA_RUNTIME_LIBRARY="Shared"
+else
+  module load Hypre/3.0.0-cpu
+fi
+
+# ICON additional libraries
+module load ecCodes
+
+# Set default MPI compilers
+export CC=mpicc
+export FC=mpif90
+export CXX=mpicxx
+
+# Variables read by TSMP2 cmake scripts
+export MPI_HOME=$EBROOTPSMPI
+export UMPIRE_ROOT=$EBROOTUMPIRE
+export SUNDIALS_ROOT=$EBROOTSUNDIALS
+
+# Display compiler settings
+module list
+echo "=============== COMPILER SETTINGS  ==============="
+echo "   Machine: ${SYSTEMNAME} on Stages/$STAGE"
+echo "   MPI lib: ParaStationMPI v$EBVERSIONPSMPI"
+echo "         C: $($CC --version | head -n 1)"
+echo "       C++: $($CXX --version | head -n 1)"
+echo "   Fortran: $($FC --version | head -n 1)"
+if [[ "$1" == "--parflowgpu" ]]; then
+  echo "      nvcc: $(nvcc --version | tail -n 1 | cut -d" " -f2)"
+  echo " CUDAARCHS: $CUDAARCHS"
+fi
+echo "=================================================="
+echo ""
+
diff --git a/env/jsc.2026.intel.psmpi b/env/jsc.2026.intel.psmpi
new file mode 100644
index 00000000..33831ef3
--- /dev/null
+++ b/env/jsc.2026.intel.psmpi
@@ -0,0 +1,82 @@
+# --------------------------------------------------------------------------
+# Loads IntelLLVM+ParaStationMPI build environment for TSMP2.
+# This environment is tailored for JURECA [1] and JUWELS [2] supercomputers.
+#
+# [1] https://apps.fz-juelich.de/jsc/software/jureca/index.xhtml
+# [2] https://apps.fz-juelich.de/jsc/software/juwels/index.xhtml
+# 
+# Usage: source jsc.2026.intel.psmpi
+# --------------------------------------------------------------------------
+
+# Load Stages/2026
+module --force purge
+module use $OTHERSTAGES
+module load Stages/2026
+
+# Primary compiler toolchain
+if [[ "$1" == "--parflowgpu" ]]; then
+  # TODO: Use a generic GPU switch instead of --parflowgpu
+  module load CUDA
+fi
+module load Intel
+module load ParaStationMPI
+
+# Basic scripting and build tools
+module load Python
+module load CMake
+module load git
+
+# Storage libraries
+module load HDF5
+module load netCDF
+module load netCDF-Fortran
+module load PnetCDF
+
+# ParFlow additional libraries
+if [[ "$1" == "--parflowgpu" ]]; then
+  module load CUDA
+  module load UCX-settings/RC-CUDA
+  module load Hypre/3.0.0
+  module load Umpire
+
+  # TODO: Verify these values
+  export CUDAARCHS="80"
+  export CMAKE_CUDA_RUNTIME_LIBRARY="Shared"
+else
+  module load Hypre/3.0.0-cpu
+  module load Umpire
+fi
+module load Tcl
+
+# ICON additional libraries
+module load ecCodes
+
+# Set default MPI compilers
+export OMPI_CC=icx
+export OMPI_CXX=icpx
+export OMPI_FC=ifx
+export CC=mpicc
+export FC=mpif90
+export CXX=mpicxx
+export MPI_HOME=$EBROOTPSMPI
+export TSMP2_PARALLEL_JOBS=16
+
+# Display compiler settings
+module list
+echo "====================================== COMPILER SETTINGS ======================================"
+echo "   Machine: ${SYSTEMNAME} on Stages/$STAGE"
+echo "   MPI lib: $(mpichversion | head -n 1 | tr -d =)"
+echo "         C: $($CC --version | head -n 1)"
+echo "       C++: $($CXX --version | head -n 1)"
+echo "   Fortran: $($FC --version | head -n 1)"
+if [[ "$1" == "--parflowgpu" ]]; then
+  echo "      nvcc: $(nvcc --version | tail -n 1 | cut -d" " -f2)"
+  echo " CUDAARCHS: $CUDAARCHS"
+fi
+echo "==============================================================================================="
+echo ""
+if [[ "$1" == "--parflowgpu" ]]; then
+  echo "WARNING: ParFlowGPU doesn't work on Intel toolchain due to missing Intel-built Hypre-CUDA library."
+  echo "         Load the 'jsc.2025.gnu.openmpi' env file instead to build ParFlowGPU."
+fi
+echo ""
diff --git a/env/jsc.2026.nvhpc.openmpi b/env/jsc.2026.nvhpc.openmpi
index 0606c818..31c28044 100644
--- a/env/jsc.2026.nvhpc.openmpi
+++ b/env/jsc.2026.nvhpc.openmpi
@@ -32,7 +32,11 @@ module load CUDA
 module load UCX-settings/RC-CUDA
 module load Hypre
 module load Umpire
-module load SUNDIALS
+#
+# TODO: Make Parflow+SUNDIALS work on NVHPC.
+# Currently Parflow+SUNDIALS produces build errors.
+# module load SUNDIALS
+#
 
 # TODO: Verify these values
 if [[ $SYSTEMNAME == "jupiter" ]]; then
@@ -48,11 +52,17 @@ module load ecCodes
 # Set default MPI compilers
 export CC=mpicc
 export FC=mpifort
-export CXX=nvc++
-export CUDACXX=nvcc
+export CXX=mpicxx
+
+# OMPI_* variables affect OpenMPI backend compilers. They should be
+# unset so that the correct default backend compilers are selected.
+unset OMPI_CC OMPI_FC OMPI_CXX
+
+# Variables read by TSMP2 cmake scripts
+export CUDACXX=$(which nvcc)
 export MPI_HOME=$EBROOTOPENMPI
 export UMPIRE_ROOT=$EBROOTUMPIRE
-export SUNDIALS_ROOT=$EBROOTSUNDIALS
+#export SUNDIALS_ROOT=$EBROOTSUNDIALS
 export TSMP2_PARALLEL_JOBS=16
 
 # Display compiler settings
@@ -63,5 +73,7 @@ echo "   MPI lib: OpenMPI v$EBVERSIONOPENMPI"
 echo "         C: $($CC --version | head -n 2 | tail -n 1)"
 echo "       C++: $($CXX --version | head -n 2 | tail -n 1)"
 echo "   Fortran: $($FC --version | head -n 2 | tail -n 1)"
+echo "      nvcc: $(nvcc --version | tail -n 1 | cut -d" " -f2)"
+echo " CUDAARCHS: $CUDAARCHS"
 echo "======================================================================"
 
diff --git a/models/eCLM b/models/eCLM
index 8d9ca1ea..57115693 160000
--- a/models/eCLM
+++ b/models/eCLM
@@ -1 +1 @@
-Subproject commit 8d9ca1ea7a3418335527568417a889ef3f259634
+Subproject commit 57115693bd0818edec6ef1241aed5b3668bbaaa1
diff --git a/models/oasis3-mct b/models/oasis3-mct
index 5253349d..554c09fd 160000
--- a/models/oasis3-mct
+++ b/models/oasis3-mct
@@ -1 +1 @@
-Subproject commit 5253349d4ce15259fcd76e0443495c1ddb7788bb
+Subproject commit 554c09fd88412086d85fc778cdb52fd2ea9e5361
diff --git a/models/parflow_pdaf b/models/parflow_pdaf
index fa51ec62..f8e18e1b 160000
--- a/models/parflow_pdaf
+++ b/models/parflow_pdaf
@@ -1 +1 @@
-Subproject commit fa51ec6265e1d95b64c423c3dc4cb2b998573e15
+Subproject commit f8e18e1be291031d18020fef78a46cadb7753bb1