Switch to total land-ice flux in melt time series

We still use the old variable if necessary for backwards
compatibility.

mpas_analysis/ocean/time_series_antarctic_melt.py

@@ -80,7 +80,8 @@ def __init__(self, config, mpasTimeSeriesTask, regionMasksTask,
             # nothing else to do
             return
 
-        masksSubtask = regionMasksTask.add_mask_subtask(regionGroup=regionGroup)
+        masksSubtask = \
+            regionMasksTask.add_mask_subtask(regionGroup=regionGroup)
         self.iceShelfMasksFile = masksSubtask.geojsonFileName
 
         iceShelvesToPlot = masksSubtask.expand_region_names(iceShelvesToPlot)
@@ -185,8 +186,7 @@ def __init__(self, parentTask, startYear, endYear, mpasTimeSeriesTask,
         self.endYear = endYear
         self.startDate = f'{self.startYear:04d}-01-01_00:00:00'
         self.endDate = f'{self.endYear:04d}-12-31_23:59:59'
-        self.variableList = \
-            ['timeMonthly_avg_landIceFreshwaterFlux']
+        self.variableList = None
 
     def setup_and_check(self):
         """
@@ -230,6 +230,13 @@ def setup_and_check(self):
             raise IOError('No MPAS-O restart file found: need at least one '
                           'restart file for Antarctic melt calculations')
 
+        totalFluxVar = 'timeMonthly_avg_landIceFreshwaterFluxTotal'
+        landIceFluxVar = 'timeMonthly_avg_landIceFreshwaterFlux'
+        if totalFluxVar in self.mpasTimeSeriesTask.allVariables:
+            self.variableList = [totalFluxVar]
+        else:
+            self.variableList = [landIceFluxVar]
+
         self.mpasTimeSeriesTask.add_variables(variableList=self.variableList)
 
         return
@@ -309,13 +316,20 @@ def run_task(self):
 
         regionNames = decode_strings(dsRegionMask.regionNames)
 
+        totalFluxVar = 'timeMonthly_avg_landIceFreshwaterFluxTotal'
+        landIceFluxVar = 'timeMonthly_avg_landIceFreshwaterFlux'
+
+        if totalFluxVar in dsIn:
+            fluxVar = totalFluxVar
+        else:
+            fluxVar = landIceFluxVar
+
         datasets = []
         nTime = dsIn.sizes['Time']
         for tIndex in range(nTime):
             self.logger.info(f'  {tIndex + 1}/{nTime}')
 
-            freshwaterFlux = \
-                dsIn.timeMonthly_avg_landIceFreshwaterFlux.isel(Time=tIndex)
+            freshwaterFlux = dsIn[fluxVar].isel(Time=tIndex)
 
             nRegions = dsRegionMask.sizes['nRegions']
             meltRates = numpy.zeros((nRegions,))