The Effect Of Solar Flares On The Oi Green Line Of The Nightglow

The Venusian 5577.3 Å OI (1S - 1D) (oxygen green line) nightglow emission is known to be highly temporally variable. The reason for this variability is unknown. We propose that the emission is due to electron precipitation from intense solar storms. For my dissertation, I observed the Venusian green line after solar flares, coronal mass ejections (CMEs), and co-rotating interaction regions from December 2010 to April 2015 using the high resolution Astrophysical Research Consortium Echelle Spectrograph on the Apache Point Observatory 3.5-m telescope. Combining these observation with all other published observations, we find that the strongest detections occur after CME impacts and we conclude electron precipitation is required to produce green line emission. We do not detect emission from the 6300.3 Å OI (1D - 3P) oxygen red line for any observation. In an effort to determine the emitting altitude, thereby constraining the possible emission processes responsible for green line emission, and quantify the electron energy and flux entering the Venusian nightside, we conducted analyses of space-based observations of the Venusian nightglow and ionosphere collected by the Venus Express (VEX) spacecraft. We were unable to detect the green line but confirmed that electron energy and flux increases after CME impacts. In order to determine the effect of storm condition electron precipitation on the Venusian green line, we modeled the Venusian ionosphere using the TRANSCAR model (a 1-D magnetohydrodynamic ionospheric model that simulates auroral emission from electron precipitation) by applying observed electron energies and fluxes. We found that electron energy plays a primary role in producing increased green line emission in the Venusian ionosphere. Based on observation and modeling results, we conclude that the Venusian green line is an auroral-type emission that occurs after solar storms with the largest intensities observed after CMEs. Post-CME electron fluxes and energies are sufficient to produce the observed green line intensity with the lack of red line emission. We find that O + e is the greatest contributor to the OI (1S) state and is responsible for the observed green line emission.

The cumulus cloud events of the Florida peninsula that were observed during a 19-day period of photoreconnaissance in August and September 1957 are described and illustrated. The associated meteorological and rainfall events are also described and the intercorrelations among the various observations are pointed out. The study findings revealed that the principal factors governing the cloud and rainfall situations of the different days were (1) the low-level advection of water vapor into the peninsula from the oceanic surroundings, (2) the wind transport, into the heated peninsula from the oceans during the daytime, of pre -existing cumulus populations containing appreciable liquid water, (3) the low-level convergence, and associated updraft motion, engendered by the synoptic situation and the peninsula sea breezes, and (4) the precipitable water content of the lower Florida air mass. (Author)