Effects of solar cycle variations on oxygen green line emission rate over Kiso, Japan

Abstract

A sixteen year long dataset of mesospheric OI 557.7 nm green line nightglow emission rate, measured over Kiso (35.79 • N, 137.63• E), Japan using ground-based photometers is spectrally investigated using the HilbertHuang Transform (HHT). The spectrograms reveal the presence of semi-annual, annual and quasi-biennial oscillations in consonance with the results obtained from wavelet analysis in an earlier study. In addition, due to the use of the HHT, we have been able to investigate the very low frequency solar cycle variation in the emission rate. It is found that there is a signi cant solar cycle effect on the oxygen green line emission rate. The mean amplitude of variation is approximately 20% and it is also found that it is maximum at midnight. A correlation study between the means of the emission rate and the solar radio ux at 10.7 cm also shows that the effect of solar activity on the oxygen green line emission rate is maximum at midnight.

Nighttime atomic oxygen in the mesopause region retrieved from SCIAMACHY O(1S) green line measurements and its response to solar cycle variation

“…Therefore, it cannot be expected that solar maximum/minimum ratios are independent of solar local time. This was confirmed by Das et al [], who found that the solar cycle impact on the green line emission rate is dependent on the local time, changing from 15% to 30% during the night and reaching its maximum at midnight.…”

“…These differences might also be related to the different local time sampling of the two instruments, because SCIAMACHY data covers a fixed local time only, whereas WINDII data covers all local solar times during the night. A local time dependence of the 11 year solar cycle in the green line radiance was indeed observed by the ground‐based measurements at Kiso (35.79°N, 137.63°E) [ Das et al , ] indicating around 40% solar maximum/minimum differences. The Buckland Park Field station (34.6°S, 138.6°E) observed the solar maximum/minimum differences of around 34 ± 14% [ Reid et al , ].…”

Long-Term Changes in Night Time Airglow Emission at 557.7 nm over Mid Latitude Japanese Station i.e., Kiso (35.79oN, 137.63oE)

“…Rajesh et al [23], have reported the ionospheric plasma depletion phenomenon over Kavalur i.e., Indian low latitude station using the nighttime airglow intensity measurements at 557.7 nm. Effect of seasonal, solar cycle variation and determination of different range of periodicities from a few days to less than one solar cycle on nighttime airglow intensity of 557.7 nm over Kiso, was also described by Das et al [24,25]. But earlier workers have not attempted to such rare studies on long-term trend behavior on nighttime airglow emission intensity at 557.7 nm.…”

“…Thus, studies of long-term variation on mesospheric airglow specifically based on experimentally observed data and its possible causes are either rare or few [23][24][25]. Rajesh et al [23], have reported the ionospheric plasma depletion phenomenon over Kavalur i.e., Indian low latitude station using the nighttime airglow intensity measurements at 557.7 nm.…”

Simulations of airglow variations induced by the CO2 increase and solar cycle variation from 1980 to 1991

“…Therefore, it is expected that airglow intensity would also change in response to solar variations. There have been quite a few studies on airglow intensity or airglow temperature variations caused by the 11-year solar cycles using airglow observations [Scheer et al, 2005;Azeem et al, 2007;Pertsev and Perminov, 2008;Beig et al, 2008;Das et al, 2011]; however, no definitive correlation has been established.…”