average of the two-dimensional power spectrum within an $\ell$-bin $b$, $$\label{eqn:ddef}
 \widehat{D}^{\nu_i x \nu_j, AB}_b\equiv \left< \frac{\ell(\ell+1)}{2\pi}H_\ell \mathrm{Re}\left[\tilde{m}^{\nu_i,A}_{\ell}\tilde{m}^{\nu_j,B*}_{\ell}\right] \right>_{\ell \in b},$$ where $H_\ell$ is a two-dimensional weight array described below and $\tilde{m}^{\nu_i, A}$ is the Fourier transformed map. Here, $\nu_i, \nu_j$ are the observation frequencies (e.g., 150GHz) and $A, B$ are the observation indices. We average all cross-spectra $\widehat{D}^{AB}_b$ for $A \neq B$ to calculate binned power spectrum $\widehat{D}_b$ for each field. We refer to the power within a bin $b$ as defined by equation \[eqn:ddef\] as a “bandpower."

The maps have anisotropic noise due to the observation strategy and TOD filtering. At low $\ell$, modes perpendicular to the scan direction ($\ell_x=0$) are noisier than those parallel to the scan direction ($\ell_y = 0$). R12 addressed this by simply masking modes at $\ell_x < 1200$. In this work, we instead follow the weighting procedure used in K11. We construct a two-dimensional weight array $H_\ell$, defined as $$\label{eqn:2dweight}
H_{\ell} \propto (C_\ell^{\mathrm{th}} + N_{\ell})^{-2} \,,$$ where $C_\ell^{\mathrm{th}}$ is the theoretical power spectrum used in simulations described in section \[sec:sims\], and $N_{\ell}$ is the two-dimensional, calibrated, beam-deconvolved noise power. $N_\ell$ is calculated from difference maps between scans going in opposite directions. In most 