Comparison of gas density at position of Rosetta orbiter predicted by models (n^mod, green) with homogeneous surface (left panels: instantaneous energy input, right panels: rotation-averaged energy input) and COPS measurements (n^NG, red): in August–November 2014 (top row), in September 15–October 30, 2014 (middle row), and in October 8–12 (bottom row). The bottom part of each panel shows cometocentric distance Δ, colatitude θ_SC, and phase angle α of the orbiter. The horizontal axis shows the date (yy-mm-dd).