Left: average OLR value assigned to each of the 18 ten-degree zonal segments. We note the different average OLR near the north and south poles of Earth and the maximum radiation at the tropics. In this example no thermal radiation from segments south of 70°S would be received at the lunar location due to obstruction by the horizon. Right: average zonal OLR (black line, courtesy of Kevin Trenberth and Yongxin Zhang) and the average for each ten-degree zonal segment used in this study (red crosses).