diff --git a/zppy_interfaces/global_time_series/coupled_global.py b/zppy_interfaces/global_time_series/coupled_global.py
index b07bee8..ea0be12 100644
--- a/zppy_interfaces/global_time_series/coupled_global.py
+++ b/zppy_interfaces/global_time_series/coupled_global.py
@@ -165,7 +165,7 @@ def set_var(
     new_var_list: List[Variable] = []
     if exp[exp_key] != "":
         try:
-            dataset_wrapper: DatasetWrapper = DatasetWrapper(exp[exp_key])
+            dataset_wrapper: DatasetWrapper = DatasetWrapper(exp[exp_key], var_list)
         except Exception as e:
             logger.critical(e)
             logger.critical(
@@ -253,16 +253,16 @@ def process_data(
 
         # Optionally read ohc
         if exp["ocean"] != "":
-            dataset_wrapper = DatasetWrapper(exp["ocean"])
-            exp["annual"]["ohc"], _ = dataset_wrapper.globalAnnual(Variable("ohc"))
+            ohc_variable = Variable("ohc")
+            dataset_wrapper = DatasetWrapper(exp["ocean"], [ohc_variable])
+            exp["annual"]["ohc"], _ = dataset_wrapper.globalAnnual(ohc_variable)
             # anomalies with respect to first year
             exp["annual"]["ohc"][:] = exp["annual"]["ohc"][:] - exp["annual"]["ohc"][0]
 
         if exp["vol"] != "":
-            dataset_wrapper = DatasetWrapper(exp["vol"])
-            exp["annual"]["volume"], _ = dataset_wrapper.globalAnnual(
-                Variable("volume")
-            )
+            vol_variable = Variable("volume")
+            dataset_wrapper = DatasetWrapper(exp["vol"], [vol_variable])
+            exp["annual"]["volume"], _ = dataset_wrapper.globalAnnual(vol_variable)
             # annomalies with respect to first year
             exp["annual"]["volume"][:] = (
                 exp["annual"]["volume"][:] - exp["annual"]["volume"][0]
diff --git a/zppy_interfaces/global_time_series/coupled_global_dataset_wrapper.py b/zppy_interfaces/global_time_series/coupled_global_dataset_wrapper.py
index cd5e3dc..7af8a63 100644
--- a/zppy_interfaces/global_time_series/coupled_global_dataset_wrapper.py
+++ b/zppy_interfaces/global_time_series/coupled_global_dataset_wrapper.py
@@ -1,4 +1,4 @@
-from typing import Tuple
+from typing import Any, List, Optional, Tuple
 
 import xarray
 import xcdat
@@ -10,16 +10,20 @@
 
 
 class DatasetWrapper(object):
-    def __init__(self, directory):
+    def __init__(self, directory: str, var_list: List[Variable]):
 
         self.directory: str = directory
 
         # `directory` will be of the form `{case_dir}/post/<component>/glb/ts/monthly/{ts_num_years_str}yr/`
+        file_path_list: List[str] = []
+        for var in var_list:
+            # `var` will be of the form `FSNS`, `FLNS`, etc.
+            file_path_list.append(f"{directory}{var.variable_name}*.nc")
         self.dataset: xarray.core.dataset.Dataset = xcdat.open_mfdataset(
-            f"{directory}*.nc", center_times=True
+            file_path_list, center_times=True
         )
 
-        self.area_tuple = None
+        self.area_tuple: Optional[Tuple[Any, Any, Any]] = None
 
     def set_area_tuple(self):
         keys = list(self.dataset.keys())