Wavelets on the sphere. Application to the detection problem
  A new method is presented for the construction of a natural continuous wavelet transform on the sphere. It incorporates the analysis and synthesis with the same wavelet and the definition of translations and dilations on the sphere through the spherical harmonic coefficients. We construct a couple of wavelets as an extension of the flat Mexican Hat Wavelet to the sphere and we apply them to the detection of sources on the sphere. We remark that no projections are used with this methodology. 
J.L. Sanz, D. Herranz, M. Lopez-Caniego and F. Argueso