code: def load_obs(self):
          
          track_total_file = self.track_data_csv_path + \
              "track_total_{0}_{1}_{2}.csv".format(self.ensemble_name,
                                                   self.ensemble_member,
                                                   self.run_date.strftime("%Y%m%d"))
          track_step_file = self.track_data_csv_path + \
              "track_step_{0}_{1}_{2}.csv".format(self.ensemble_name,
                                                  self.ensemble_member,
                                                  self.run_date.strftime("%Y%m%d"))
          track_total_cols = ["Track_ID", "Translation_Error_X", "Translation_Error_Y", "Start_Time_Error"]
          track_step_cols = ["Step_ID", "Track_ID", "Hail_Size", "Shape", "Location", "Scale"]
          track_total_data = pd.read_csv(track_total_file, usecols=track_total_cols)
          track_step_data = pd.read_csv(track_step_file, usecols=track_step_cols)
          obs_data = pd.merge(track_step_data, track_total_data, on="Track_ID", how="left")
          self.obs = obs_data
docs: Loads the track total and step files and merges the information into a single data frame.