Modeling the effect of the 11-year solar cycle on mesospheric temperatures

1. Modeling the effect of the 11-year solar cycle on mesospheric temperatures LWS03-0102-0052: John McCormack & David Siskind, Naval Research Laboratory, Washington DC Estimated SABER solar max - solar min DT = 6-7 K CHEM2D modeled solar max - solar min DT = 5-6 K SABER temperatures (points) at 0.002 hPa (~85 km) as a function of solar 10.7cm flux progressing from higher solar activity in 2002 to lower solar activity in 2005. Encl (7)

2. This figure shows average winter Southern Hemisphere (60oS - 80oS ) temperatures at 0.002 hPa (~85 km) from the SABER (Sounder of the Atmosphere using Broadband Emission Radiometry) instrument on board the NASA TIMED satellite over the period of declining solar activity from 2002-2005. The SABER data indicate a temperature decrease consistent with the modeled temperature response to declining solar activity. Since these measurements are in polar night, the solar cycle response is likely an indirect effect due to transport of photochemically altered constituents (e.g., O) from sunlit regions. This altitude corresponds to the region of peak Meinel band OH* emissions. The SABER SH temperature difference at 85 km over a full cycle is estimated to be 6-7 K, which is comparable to the 5-6 K difference we obtain with the CHEM2D model. This agrees with recent published results from Michelson Interferometer measurements of the OH airglow from the South Pole. Modeling the effect of the 11-year solar cycle on mesospheric temperatures