Absorption measurements of upper-atmospheric sodium at Boca Raton, Florida, 1967-1971

Section: Introductionmentioning

confidence: 63%

diurnal variation of the sodium dayglow

Chanin¹,

Goutail²

1975

“…Purdy, 1970; Albano et al, 1970]. Likewise, the direct absorption results obtained by Burnett et al [1972], as well as the laser data obtained by Gibson and Sandford [1972], showed little or no diurnal variation. However, the direct absorption.…”

mentioning

confidence: 79%

“…Fabry-Perot spectrometer. The detailed description of this system is given elsewhere Roeder and Mack, 1967;Burnett et al, 1972;Roeder, 1974]. The three Because the terrestrial sodium absorption is normally very weak, it was possible in this experiment to convert each computed equivalent width w measured in units per centimeter to an abundance value ,4 from the following linear curve of growth:…”

mentioning

confidence: 90%

Absorption studies of daytime sodium abundance

Partowmah¹,

Roesler²

1977

On the basis of the analysis of approximately 3000 high spectral resolution scans of the direct absorption of sunlight by atmospheric sodium atoms the average seasonal and diurnal variations of atomic sodium abundance in the upper atmosphere have been deduced for Madison, Wisconsin (43°4.5′N, 80°24.3′W). For the period 1971–1974 an average maximum abundance of 7.7 × 109 atoms/cm² was observed to occur in early March and an average minimum of 2.9 × 109 atoms/cm² in late August. The abundance at local noon relative to the abundance ±4½ hours away from noon averaged 2.3 for the period of January and February and between 1.3 and 1.7 for the remainder of the year, with the minimum in June. The diurnal abundance variation in the winter appears to show a correlation with snow cover, suggesting a relationship with changes in the earth's albedo.

“…The existence of atomic sodium in the Earth's atmosphere has been known for over 40 years [Chapman, 1939]. The results of subsequent ground-based and air-borne experiments indicate that atmospheric sodium is located at about 90-km altitude in the form of a layer approximately 15 km thick [Gault and Rundle, 1969 Burnett et al, 1972;Partowmah, 1975;Gibson and Sanford, 1972]. Another pronounced character of the atomic sodium abundances is the rapid variability during the day.…”

Section: Introductionmentioning

confidence: 99%

Investigation of sodium in the upper atmosphere

Yeringil¹,

Öğelman²,

Kiziloglu³

1980

Upper atmospheric atomic sodium abundances have been measured near Ankara (39.9°N, 32.6°E), Turkey, from February 1976 to April 1977. The daytime absorption measurements were made with a Pepsios spectrometer using the solar radiation near the D2 line of sodium at 5890 Å. Seasonal and daily variations of the sodium abundance were examined. A seasonal variation appears to be present with maximum abundance values occurring near the end of February and minimum values occurring in April. No significant evidence was found for diurnal variations. However, there is some evidence for shorter‐period fluctuations with periods between 25 and 108 min. A model is proposed in which the atomic sodium has a cloudlike structure, and the parameters obtained in this way suggest that the ‘clouds’ have a mean column density of 1.5×109 atoms/cm2.