code: def __call__(self):
      tau_step = np.linspace(
          self._taustep4sphalb,
          MAXNUMSPHALBVALUES * self._taustep4sphalb,
          MAXNUMSPHALBVALUES,
      )
      sphalb0 = _csalbr(tau_step)
      taur = self._tau * np.exp(-self._height / SCALEHEIGHT)
      rhoray, trdown, trup = _chand(
          self._phi, self._muv, self._mus, taur
      )
      sphalb = sphalb0[
          (taur / self._taustep4sphalb + 0.5).astype(np.int32)
      ]
      Ttotrayu = (
          (2 / 3.0 + self._muv) + (2 / 3.0 - self._muv) * trup
      ) / (4 / 3.0 + taur)
      Ttotrayd = (
          (2 / 3.0 + self._mus) + (2 / 3.0 - self._mus) * trdown
      ) / (4 / 3.0 + taur)
  
      tH2O = self._get_th2o()
      TtotraytH2O = Ttotrayu * Ttotrayd * tH2O
  
      tO2 = self._get_to2()
      tO3 = self._get_to3()
      tOG = tO3 * tO2
      return sphalb, rhoray, TtotraytH2O, tOG
  
imports: from __future__ import annotations
  import logging
  from typing import Optional, Type, Union
  import dask.array
  import numpy
  import xarray
  from satpy.dataset.dataid import WavelengthRange
label_desc: Use image node_id 2 for calling the _AtmosphereVariables obj's underlying member method code with example usage: obj.__call__() and returns: sphalb,  rhoray,  TtotraytH2O,  tOG