ON THE NET HEATING OF AURORAL JET CURRENTS IN THE POLAR MESOPAUSE REGION

Assuming that the cooling-to-space of the atmosphere in the mesopause region around 100km altitude is caused by CO_2 15μm band radiation, the efficiency is reduced to one twentieth or less that calculated on the condition of local thermodynamic equilibrium (J. T. HOUGHTON : The Physics of Atmospheres, 2nd ed., Cambridge, Cambridge Univ. Press, 57,1986). The amount of joule heating in this region of auroral belt during substorm period is calculated from ground based magnetometer observations (Y. KAMIDE and A. D. RICHMOND : Geophys. Monogr., 28,67,1984). Combining the above mentioned cooling and heating effects one can calculate the amount of net heating. The result shows that 1.3°K warming, which should require one day before cooling, may be attained by only one hour substorm duration. This may have significance in considering the dynamical effect of solar activity in the global atmosphere such as discussed by K. LABITZKE and H. VAN LOON (J. Atmos. Terr. Phys., 50,197,1988)