Difference between DMSP probe Te measurements and simultaneous Millstone Hill incoherent scatter measurements versus the solar activity index PF10.7 = (F10.7D + F10.7_81)/2 with F10.7D the daily solar radio flux index F10.7 and F10.7_81 the 81 day average of F10.7. The 540 coincidences from the time period 1996 to 2006 are separated into daytime (+) and night-time (◊) and also include a least-square fitted linear approximation (broken curve) with the formula given at the bottom.