def compute_relBIAS_map_healpix(pred, obs):
    """ Compute the relative bias from two xr.DataArrays given some dimensions
    
    Parameters
    ----------
    pred : xr.DataArray
        Forecast. Time coordinate must be validation time.
    obs_mean : xr.DataArray
        Mean of observations across "time" and "lead_time" dimensions
    
    Returns
    -------
    relBIAS : xr.DataArray
        Relative bias map
    """
    error = pred - obs
    rbias = error.mean(('time')).load() / obs.mean(('time')).load()
    return rbias