  We estimate Cosmic Microwave Background (CMB) polarisation power spectra, and
temperature-polarisation cross-spectra, from the 9-year data of the Wilkinson
Microwave Anisotropy Probe (WMAP). Foreground cleaning is implemented using
minimum variance linear combinations of the coefficients of needlet
decompositions of sky maps for all WMAP channels, to produce maps for CMB
temperature anisotropies (T-mode) and polarisation (E-mode and B-mode), for 9
different years of observation. The final power spectra are computed from
averages of all possible cross-year power spectra obtained using
foreground-cleaned maps for the different years. Our analysis technique yields
a measurement of the EE spectrum that is in excellent agreement with
theoretical expectations from the current cosmological model. By comparison,
the publicly available WMAP EE power spectrum is higher on average (and
significantly higher than the predicted EE spectrum from the current best fit)
at scales larger than about a degree, an excess that is not confirmed by our
analysis.
