Improving our ability to predict and mitigate the impacts of ionospheric scintillation on satellite communication and navigation systems requires new observations of the global morphology and climatology of scintillation-causing irregularities. The SSUSI (Special Sensor Ultraviolet Spectrographic Imager) instruments on-board the DMSP F16 and F18 satellites have global observations of the ionosphere at 8 PM local time from 2004 to the present. We have developed a technique for reconstructing three-dimensional ionospheric electron density profiles from SSUSI UV brightness observations at 135.6 nm. We also have developed a technique that routinely detects equatorial plasma bubbles in SSUSI data. Here we present a climatology of SSUSI plasma bubble observations (occurrence frequency as a function of parameters such as longitude, season, solar activity, etc.) which is the most comprehensive set of global observations ever at 8 PM local time. We also present three-dimensional electron density profile reconstructions which capture the morphology of large-scale gradients and density depletions. Finally, we explore the potential of these observed irregularities to interfere with trans-ionospheric communication at various frequencies.