Is there enough solar extreme ultraviolet radiation to maintain the global mean thermospheric temperature?

The global mean temperature profile of the neutral thermosphere above 120 km is calculated using the solar EUV flux tabulation of H. E. Hinteregger (1970) for wavelengths less than 1310 A and the data of K. G. Widing et al. (1970) for wavelengths greater than 1310 A. With a heating efficiency of 0.33, the calculated global mean exospheric temperature is 700°K. This temperature does not lie within the range of the 900° to 1050°K global mean temperature obtained from the model of L. G. Jacchia (1971) for the range of solar F10.7 emission suggested by H. E. Hinteregger (1970) as appropriate to his data. The electron temperature in the ionosphere is also calculated using the solar EUV flux and is compared with the data of J. V. Evans (1971). The calculated electron temperature is also considerably lower than the measured values. Calculations show that a doubling of the solar EUV flux for wavelengths less than 1310 A is required to bring both the neutral and electron temperatures into reasonable agreement with observations.