Measurements of atmospheric sodium abundance by direct absorption of sunlight

Graduation date: 1989The atmospheric sodium daytime abundance was measured for\ud Corvallis, Oregon, using direct absorption of sunlight by atmospheric\ud sodium atoms, as observed with an optical waveguide spectrum analyzer.\ud The disadvantage of the spectrum analyzer is that it can't resolve the\ud sodium D-lines (Its resolving power is 0.5 nm, which is approximately\ud the same as the wavelength separation of the sodium D lines). The data\ud analysis is based on a model developed specifically for atomic\ud absorption of resonance radiation. In this model only the first order\ud approximation was considered, and any further development of the model\ud needs to consider the higher order terms. A daytime variation in the\ud atmospheric sodium abundance having a maximum at around noon was\ud observed. Also, a day-to-day variation in the atmospheric sodium\ud abundance was observed. The results obtained in this experiment are\ud consistent with previous results obtained at Madison, Wisconsin, by\ud measuring the atmospheric transmission of sunlight at the Na D2\ud wavelength using a high resolution multiple Fabry-Perot spectrometer