FIX: Use existing time extraction in Py-ART in columnsect (#1529)

pyart/util/columnsect.py

@@ -9,6 +9,7 @@
 import xarray as xr
 
 from ..core.transforms import antenna_vectors_to_cartesian
+from .datetime_utils import datetime_from_radar
 
 
 def column_vertical_profile(
@@ -350,8 +351,7 @@ def get_field_location(radar, latitude, longitude):
 
     # Determine the time at the center of each ray within the column
     # Define the start of the radar volume as a numpy datetime object for xr
-    # We take advantage of the "seconds since " portion of the units string
-    base_time = pd.to_datetime(radar.time["units"][14:]).to_numpy()
+    base_time = np.datetime64(datetime_from_radar(radar).isoformat())
     # Convert Py-ART radar object time (time since volume start) to time delta
     # Add to base time to have sequential time within the xr Dataset
     # for easier future merging/work