Telluric absorption, residual intensities, and shifts in the Fraunhofer D lines

Abstract

The shapes of the D lines, integrated over the solar disk, have been observed from Madison, Wisconsin, United States, for a year, with spectroscopic resolution sufficient to resolve the ground‐state hyperfine structure of sodium in telluric absorption. An annual upper‐atmosphere sodium abundance plot shows an autumn maximum of (8±2)× 09 atoms/cm2 and no detectable sodium from April to August 1961. The observations in a single day show definite, apparently random, variations. Several other telluric absorption lines in the neighborhood are listed. Out to about 220 mK or 13 ppm from the line centers, the profiles of intensity I (relative to the continuum), corrected for telluric absorption, follow the expression I = I0 exp (|x|/xe)A, withI0 xeA D1(λ5896) 0.0495 217 mK or 12.8 ppm 2.14 ±0.0010 ±6 mK ±0.4 ppm ±0.10 D2(λ5890) 0.0444 228 mK or 13.4 ppm 2.16 ±0.0010 ±6mK ±0.4 ppm ±0.12The wave numbers of the D lines, corrected for the relative motion of the earth, show a relative red shift δσ/σ = (−2.7 ± 0.4) × 10−6, indicating that the net effect of the Lindholm shift and convection currents is small compared with the computed relative gravitational shift of −2.1×10−6.

Retrieval of sodium number density profiles in the mesosphere and lower thermosphere from SCIAMACHY limb emission measurements

“…with π F (λ) being the solar irradiance (note that it is convention to use π F (λ) (see e.g., Chamberlain et al, 1958) and π belongs to the symbol and is not meant as a factor 3.14) and , which agrees for both, is used in the approximate formula by McNutt and Mack (1963). The right figure shows the SAO 2010 spectrum compared to the fully resolved approximation of the D 1 and D 2 lines taken from McNutt and Mack (1963).…”

“…The right figure shows the SAO 2010 spectrum compared to the fully resolved approximation of the D 1 and D 2 lines taken from McNutt and Mack (1963). Note that the approximate formula by McNutt and Mack (1963) is only valid close to the center of the Fraunhofer lines. The fully resolved Na Fraunhofer lines are much deeper than the lines in the SAO 2010 spectrum and the SCIAMACHY spectrum.…”

“…Figure 1 shows solar spectra for this wavelength region from SCIAMACHY, Chance and Kurucz (2010) and McNutt and Mack (1963), from which only the latter fully resolves the Na D lines. Note that the approximate formula for the spectrum measured by McNutt and Mack (1963) is only valid in the vicinity of the center of the lines. Following McNutt and Mack (1963), the solar irradiance in the vicinity of the Na D 1 and D 2 lines can be calculated for x (x is defined further below):…”

“…Note that the approximate formula for the spectrum measured by McNutt and Mack (1963) is only valid in the vicinity of the center of the lines. Following McNutt and Mack (1963), the solar irradiance in the vicinity of the Na D 1 and D 2 lines can be calculated for x (x is defined further below):…”

Retrieval of global mesospheric sodium densities from the Odin satellite

“…We use results on the Fraunhofer minima from McNutt and Mack [1963] and normalize them to the absolute photon fluxes provided by Chance and Spurr [1997]. Varying shifts of the solar Fraunhofer structure due to the Earth's motion and the Sun's gravitational red-shift must be taken into account [McNutt and Mack, 1963].…”