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We present new, full-orbit observations of the infrared phase variations ofthe canonical hot Jupiter HD 189733b obtained in the 3.6 and 4.5 micron bandsusing the Spitzer Space Telescope. When combined with previous phase curveobservations at 8.0 and 24 micron, these data allow us to characterize theexoplanet's emission spectrum as a function of planetary longitude. We utilizeimproved methods for removing the effects of intrapixel sensitivity variationsand accounting for the presence of time-correlated noise in our data. Wemeasure a phase curve amplitude of 0.1242% +/- 0.0061% in the 3.6 micron bandand 0.0982% +/- 0.0089% in the 4.5 micron band. We find that the times ofminimum and maximum flux occur several hours earlier than predicted for anatmosphere in radiative equilibrium, consistent with the eastward advection ofgas by an equatorial super-rotating jet. The locations of the flux minima inour new data differ from our previous observations at 8 micron, and we presentnew evidence indicating that the flux minimum observed in the 8 micron islikely caused by an over-shooting effect in the 8 micron array. We obtainimproved estimates for HD 189733b's dayside planet-star flux ratio of 0.1466%+/- 0.0040% at 3.6 micron and 0.1787% +/- 0.0038% at 4.5 micron; these are themost accurate secondary eclipse depths obtained to date for an extrasolarplanet. We compare our new dayside and nightside spectra for HD 189733b to thepredictions of models from Burrows et al. (2008) and Showman et al. (2009). Wefind that HD 189733b's 4.5 micron nightside flux is 3.3 sigma smaller thanpredicted by the Showman et al. models, which assume that the chemistry is inlocal thermal equilibrium. We conclude that this discrepancy is best-explainedby vertical mixing, which should lead to an excess of CO and correspondinglyenhanced 4.5 micron absorption in this region. [abridged]

3.6 and 4.5 Micron Phase Curves and Evidence for Non-Equilibrium Chemistry in the Atmosphere of Extrasolar Planet HD 189733b