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Abstract
Radiation is a key process in the atmosphere. Numerous radiative transfer codes have been developed spanning a large range of wavelengths, complexities, speeds, and accuracies. In the infrared and microwave, line-by-line codes are crucial esp. for modeling and analyzing high-resolution spectroscopic observations. Here we present Py4CAtS—PYthon scripts for Computational ATmospheric Spectroscopy, a Python re-implemen-tation of the Fortran Generic Atmospheric Radiation Line-by-line Code GARLIC, where computationally-intensive code sections use the Numeric/Scientific Python modules for highly optimized array processing. The individual steps of an infrared or microwave radiative transfer computation are implemented in separate scripts (and corresponding functions) to extract lines of relevant molecules in the spectral range of interest, to compute line-by-line cross sections for given pressure(s) and temperature(s), to combine cross sections to absorption coefficients and optical depths, and to integrate along the line-of-sight to transmission and radiance/intensity. Py4CAtS can be used in three ways: in the (Unix/Windows/Mac) console/terminal, inside the (I)Python interpreter, or Jupyter notebook. The basic design of the package, numerical and computational aspects relevant for optimization, and a sketch of the typical workflow are presented. In conclusion, Py4CAtS provides a versatile environment for “interactive” (and batch) line-by-line radiative transfer modeling.
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Stiller GP, von Clarmann T, Brühl C, Fischer H, Funke B, Glatthor N, Grabowski U, Höpfner M, Jöckel P, Kellmann S, Kiefer M, Linden A, López-Puertas M, Mengistu Tsidu G, Milz M, Steck T, Steil B. Global distributions of HO2NO2as observed by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd007212] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Nassar R, Bernath PF, Boone CD, McLeod SD, Skelton R, Walker KA, Rinsland CP, Duchatelet P. A global inventory of stratospheric fluorine in 2004 based on Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) measurements. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2006jd007395] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sharpe SW, Johnson TJ, Sams RL, Chu PM, Rhoderick GC, Johnson PA. Gas-phase databases for quantitative infrared spectroscopy. APPLIED SPECTROSCOPY 2004; 58:1452-61. [PMID: 15606959 DOI: 10.1366/0003702042641281] [Citation(s) in RCA: 244] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The National Institute of Standards and Technology (NIST) and the Pacific Northwest National Laboratory (PNNL) are each creating quantitative databases containing the vapor-phase infrared spectra of pure chemicals. The digital databases have been created with both laboratory and remote-sensing applications in mind. A spectral resolution of approximate, equals 0.1 cm(-1) was selected to avoid degrading sharp spectral features, while also realizing that atmospheric broadening typically limits line widths to 0.1 cm(-1). Calculated positional (wave- number, cm(-1)) uncertainty is </=0.005 cm(-1), while the 1sigma statistical uncertainty in absorbance values is <2% for most compounds. The latter was achieved by measuring multiple (typically >/=9) path length-concentration burdens and fitting a weighted Beer's law plot to each wavenumber channel. The two databases include different classes of compounds and were compared using 12 samples. Though these 12 samples span a range of polarities, absorption strengths, and vapor pressures, the data agree to within experimental uncertainties with only one exception.
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Affiliation(s)
- Steven W Sharpe
- Pacific Northwest National Laboratory, P. O. Box 999, Richland, Washington 99352, USA
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Irion FW, Gunson MR, Toon GC, Chang AY, Eldering A, Mahieu E, Manney GL, Michelsen HA, Moyer EJ, Newchurch MJ, Osterman GB, Rinsland CP, Salawitch RJ, Sen B, Yung YL, Zander R. Atmospheric Trace Molecule Spectroscopy (ATMOS) Experiment Version 3 data retrievals. APPLIED OPTICS 2002; 41:6968-6979. [PMID: 12463241 DOI: 10.1364/ao.41.006968] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Version 3 of the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment data set for some 30 trace and minor gas profiles is available. From the IR solar-absorption spectra measured during four Space Shuttle missions (in 1985, 1992, 1993, and 1994), profiles from more than 350 occultations were retrieved from the upper troposphere to the lower mesosphere. Previous results were unreliable for tropospheric retrievals, but with a new global-fitting algorithm profiles are reliably returned down to altitudes as low as 6.5 km (clouds permitting) and include notably improved retrievals of H2O, CO, and other species. Results for stratospheric water are more consistent across the ATMOS spectral filters and do not indicate a net consumption of H2 in the upper stratosphere. A new sulfuric-acid aerosol product is described. An overview of ATMOS Version 3 processing is presented with a discussion of estimated uncertainties. Differences between these Version 3 and previously reported Version 2 ATMOS results are discussed. Retrievals are available at http://atmos.jpl.nasa.gov/atmos.
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Affiliation(s)
- Fredrick W Irion
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA.
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Michelsen HA. ATMOS version 3 water vapor measurements: Comparisons with observations from two ER-2 Lyman-α hygrometers, MkIV, HALOE, SAGE II, MAS, and MLS. ACTA ACUST UNITED AC 2002. [DOI: 10.1029/2001jd000587] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Notholt J, Toon GC, Rinsland CP, Pougatchev NS, Jones NB, Connor BJ, Weller R, Gautrois M, Schrems O. Latitudinal variations of trace gas concentrations in the free troposphere measured by solar absorption spectroscopy during a ship cruise. ACTA ACUST UNITED AC 2000. [DOI: 10.1029/1999jd900940] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sen B, Osterman GB, Salawitch RJ, Toon GC, Margitan JJ, Blavier JF, Chang AY, May RD, Webster CR, Stimpfle RM, Bonne GP, Voss PB, Perkins KK, Anderson JG, Cohen RC, Elkins JW, Dutton GS, Hurst DF, Romashkin PA, Atlas EL, Schauffler SM, Loewenstein M. The budget and partitioning of stratospheric chlorine during the 1997 Arctic summer. ACTA ACUST UNITED AC 1999. [DOI: 10.1029/1999jd900245] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sen B, Toon GC, Osterman GB, Blavier JF, Margitan JJ, Salawitch RJ, Yue GK. Measurements of reactive nitrogen in the stratosphere. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/97jd02468] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Notholt J, Toon GC, Lehmann R, Sen B, Blavier JF. Comparison of Arctic and Antarctic trace gas column abundances from ground-based Fourier transform infrared spectrometry. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97jd00358] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abrams MC, Gunson MR, Lowes LL, Rinsland CP, Zander R. Pressure sounding of the middle atmosphere from ATMOS solar occultation measurements of atmospheric CO(2) absorption lines. APPLIED OPTICS 1996; 35:2810-2820. [PMID: 21085429 DOI: 10.1364/ao.35.002810] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A method for retrieving the atmospheric pressure corresponding to the tangent point of an infrared spectrum recorded in the solar occultation mode is described and applied to measurements made by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier-transform spectrometer. Tangent pressure values are inferred from measurements of isolated CO(2) lines with temperature-insensitive strengths by measuring the slant-column CO(2) amount and by adjusting the viewing geometry until the calculated column matches the observed column. Tangent pressures are determined with a spectroscopic precision of l%-3%, corresponding to a tangent-point height precision of 70-210 m. The total uncertainty is limited primarily by the quality of the spectra and ranges between 4% and 6% (280-420 m) for spectra with signal-to-noise ratios of 300:1 and between 4% and 10% for spectra with signal-to-noise ratios of 100:1. The retrieval of atmospheric pressure increases the accuracy of the retrieved-gas concentrations by minimizing the effect of systematic errors introduced by climatological pressure data, ephemeris parameters, and the uncertainties in instrumental pointing.
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Sen B, Toon GC, Blavier JF, Fleming EL, Jackman CH. Balloon-borne observations of midlatitude fluorine abundance. ACTA ACUST UNITED AC 1996. [DOI: 10.1029/96jd00227] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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