mathar_2004

R. J. Mathar, “Calculated refractivity of water vapor and moist air in the atmospheric window at 10 um”, Appl. Opt. 43, 928 (2004)

Source record · Catalogue · Review register

DOI: 10.1364/ao.43.000928

Source kind: theory

Recorded technique: Line-by-line calculation of the dielectric function of water vapour and moist air: a linear superposition of independent Lorentz oscillators, Eq. (1), eps = 1 + (e^2 / m eps0) sum_m N_m sum_l f_ml / (2 omega_0ml) [1/(omega + omega_0ml - i Gamma/2) - 1/(omega - omega_0ml - i Gamma/2)], n = sqrt(eps), with the oscillator strengths from HITRAN 2000’s squared transition moments, f = 2 m c omega_0 R^2 / (3 hbar e^2) (Eq. 2), and the ultraviolet from pseudospectra and measured oscillator-strength distributions; no fitted parameter (pp. 928-931).

Materials in structured entries: None recorded.

Dataset quantities: None recorded.

Contents: 0 datasets; 0 formulas.

Curation notes

Identity VALIDATED_WITH_WARNINGS by the library (no DOI printed; found by title, author and year); the first page reads Applied Optics, received 30 July 2003, footer 0003-6935/04/040928-05. Journal pages 928-932 = pdf pages 1-5. Nothing is extracted: the results are figures of air and water vapour (not curated species), and this record is cited for method (TC-721).

THE LINES (p. 929). Water: 31,646 HITRAN lines between 441 nm and 24.96 mm; CO2: 27,123 lines between 1.036 and 22.6 um (HITRAN 2000; the 2001 edition’s 31,683 water lines differ ‘indiscernibly’). Fig. 1 shows the dispersion of water (1e23 m^-3) with and without CO2 (7.076e21 m^-3), the only place CO2’s infrared contribution appears on its own (a figure, not digitised). The line list alone leaves out the electronic spectrum; adding Margoliash and Meath’s ten water pseudo-oscillators (margoliash_1978, all below 178.1 nm) lifts n by about 9e-7 at 1e23 m^-3 and brings it to Matsumoto’s 3.4 and 10.6 um cell data (Fig. 2). The HITRAN-only calculation is valid only beyond about 2.5 um (p. 931).

THE AIR MODEL (Section 4, pp. 930-931). N2, O2, H2O and CH4 with ten pseudospectral lines each (Margoliash and Meath); CO2 with Padial et al.’s discrete and continuum transitions; Ar with Eggarter’s two lines (11.62, 11.83 eV), 12 lines of Chan et al. (13.864-15.188 eV) and 450 histogram bins to 500 eV, S(0) about 13.3; Ne from Hibbert et al. and Chan et al.; densities of the Very Large Telescope site (Fig. 3: N2 1.49e25, O2 3.84e24, Ar 1.1786e23, CO2 7.076e21, Ne 3.44e20, CH4 3.06e19, O3 2.23e18, CO 1.91e18 m^-3, 746.64 hPa of dry air). He, N2O, Kr and NH3 add at most 1.3e-10, 1.05e-10, 3e-10 and 1e-10 (p. 931). No Lorentz-Lorenz local field: eps is linear in the densities, and the author states that the response is linear at all wavelengths.

STATED COMPARISONS. At 10 um the dry components fall about 1.6e-6 below Ciddor’s (1996) formula at 752.9 hPa and 1.5e-7 below it at 746.64 hPa (p. 931). The 311 and 337 um water refractivities (+2.61e-5, +2.12e-5) are within 4 % and 6 % of Bradley and Gebbie’s after density scaling (p. 929). At 28 um the calculated humid air (833.3 hPa, 26 degrees C) lies about 0.25e-4 below Bradley and Gebbie’s (2.3 +- 0.1)e-4, unexplained (p. 931); their pure N2 value 2.26e-4 ‘fits rather well’ with the calculated 2.31e-4 at 833.3 hPa. Check (2026-09-29): fit/N2 gives 2.2050e-4 at 28 um, 833.3 hPa and 26 degrees C, and 2.3135e-4 at 12 degrees C (the temperature of the paper’s Fig. 2): the calculated 2.31e-4 matches 12, not 26, degrees C; the paper does not state the temperature of that comparison.

The paper gives no compact representation of the infrared terms. Its successor, mathar_2007, adds Lorentz-Lorenz, virial densities and temperature-dependent line strengths and publishes polynomial fits.

Recorded bibliographic identity status: VALIDATED_WITH_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.

Datasets

No datasets are recorded.

Formulas

No formulas are recorded.

Corrections

No dataset errata are recorded in this source record.

Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the review register for the checks and decisions.