Joint Auger+Telescope Array working-group paper directly cross-calibrating and combining the two observatories’ independently measured energy spectra across the full sky, addressing the historical ~10% energy-scale offset between the detectors. relevance_note: the primary reconciliation of the two largest current UHECR datasets into one flux curve; the actual “how many natural collisions above LHC-equivalent energy” figure should be read off this combined spectrum rather than either detector alone.