Remove deprecated pandas loffset usage

aosstower/level_b1/nc.py

@@ -18,6 +18,7 @@ from metobscommon.util.nc import (
     write_vars,
 )
 from netCDF4 import Dataset
+from pandas.tseries.frequencies import to_offset
 
 from aosstower import schema
 from aosstower.level_00 import parser
@@ -108,7 +109,8 @@ def create_giant_netcdf(
 
     # round up each 1 minute group so data at time T is the average of data
     # from T - 1 (exclusive) to T (inclusive).
-    new_frame = frame.resample("5S", closed="right", loffset="5S").mean()
+    new_frame = frame.resample("5S", closed="right").mean()
+    new_frame.index = frame.index + to_offset("5S")
 
     # 2 minute rolling average of 5 second data (5 seconds * 24 = 120 seconds = 2 minutes)
     winds_frame_5s = new_frame[["wind_speed", "wind_east", "wind_north"]]
@@ -123,9 +125,12 @@ def create_giant_netcdf(
     if summary:
         frame = summary_over_interval(new_frame, interval_width)
     else:
-        frame = new_frame.resample(interval_width, closed="right", loffset=interval_width).mean()
+        frame = new_frame.resample(interval_width, closed="right").mean()
+        frame.index = frame.index + to_offset(interval_width)
         frame["wind_dir"] = calc.wind_vector_degrees(frame["wind_east"], frame["wind_north"])
-        frame["gust"] = new_frame["gust"].resample(interval_width, closed="right", loffset=interval_width).max()
+        new_gust = new_frame["gust"].resample(interval_width, closed="right").max()
+        new_gust.index = new_gust.index + to_offset(interval_width)
+        frame["gust"] = new_gust
     frame = frame.fillna(np.nan)
 
     if start and end: