Subauroral mesopause temperature response to solar activity in 1999-2013
A. Ammosova, G. Gavrilyeva, P. Ammosov, I. Koltovskoi
OH(6-2) rotational temperature trends and solar cycle effects are studied. Observations were carried out at the Maimaga station (63.04° N, 129.51° E) for the period August 1999 to March 2013. Measurements were conducted with an infrared spectrograph. The temperature was determined by P- branch ratio of the molecular of hydroxyl. The monthly average residuals of temperature after the subtraction of seasonal climatic component were used for a search for the solar component of temperature response. The dependence of temperatures on solar activity has been investigated using the Ottawa 10.7 cm flux as a proxy. A linear regression fitting on residual temperatures yields a solar cycle coefficient of 4.24 K /100 solar flux units (SFU). The cross-correlation analyses showed that changes of the residual temperature follow changes of solar activity with a 25 months delay. The temperature response at the delay of 25 months reaches 7 K/100 SFU. The value of the temperature trend after the subtraction of seasonal and solar components inconsiderable. The effect of geomagnetic activity on the subauroral mesopause temperature was evaluated to find the possible reasons for the time lag.