code: def _calc_essl_red(ratio):
      """Calculate values for red based on scaled and clipped ratio."""
      red_a = 1.375 - 2.67 * ratio
      red_b = -0.75 + ratio
      red = xr.where(red_a > red_b, red_a, red_b)
      red.data = da.clip(red.data, 0, 1)
      return red
  
file_path: satpy/satpy/enhancements/atmosphere.py
imports: import datetime
  import dask.array
  import xarray
label_desc: Use image node_id 3 for calling a global function with example usage: _calc_essl_red(ratio) and returns: red