Dipole directions for independent 100-multipole bins of the local power spectrum distribution from ℓ = 2 to 1500 in the SMICA map with the common mask applied. We also show the preferred dipolar modulation axis (labelled as “low-ℓ”) derived in Sect. 6.2, as well as the total direction for ℓ_max = 600 determined from WMAP-9 (Axelsson et al. 2013). The average directions determined from the two multipole ranges ℓ ∈ [2,300] and ℓ ∈ [750,1500] are shown as blue and red rings, respectively. The error on the derived direction that results from masking the data is about 60°, with only small variations related to bin size.