Comparison of spectrally resolved outgoing longwave radiation between 1970 and 2003: The ν4 band of methane

JA Griggs; JE Harries

doi:10.1117/12.621607

Comparison of spectrally resolved outgoing longwave radiation between 1970 and 2003: The ν4 band of methane

JA Griggs, JE Harries

School of Geographical Sciences

Research output: Contribution to journal › Article (Academic Journal) › peer-review

590 Downloads (Pure)

Abstract

Measurements of spectrally resolved outgoing longwave radiation recorded in 1970, 1997 and 2003 are compared to determine the change in radiative forcing over that period. The changes are shown to be in agreements with that simulated by MODTRAN, a band model, using the known changes in atmospheric temperature and greenhouse gas concentrations when the effects of noise in the observed spectra are considered. The only region where the simulations are unable to reproduce the observations is in the v4 band of methane around 1306cm-1. The methane profiles used to simulate this region of the spectrum are shown to be in good agreement with all available data and the noise levels on the spectra are small. Therefore, it is proposed that the inability to model this region lies in the model formulation. Genln2, a line-by-line model, is shown to give very different results in this particular band to those obtained using MODTRAN. Sensitivity studies show that Genln2 is also not able to fully reproduce the spectrum observed. Errors in the spectroscopic parameters are shown to be smaller than the observed discrepancy and line mixing in methane is suggested as a possible cause of the discrepancy.

Translated title of the contribution	Comparison of spectrally resolved outgoing longwave radiation between 1970 and 2003: The nu4 band of methane
Original language	English
Number of pages	12
Journal	Proceedings of SPIE
Volume	5883
DOIs	https://doi.org/10.1117/12.621607
Publication status	Published - 29 Aug 2005

Bibliographical note

Rose publication type: Journal article

Sponsorship: This work was supported by a NERC studentship.

Terms of use: Copyright 2005 Society of Photo-Optical Instrumentation Engineers. This paper was published in Proceedings of SPIE Volume: 5883 and is made available as an electronic reprint (preprint) with permission of SPIE. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.

Keywords

outgoing longwave radiation
spectrum
greenhouse gases
simulation
infrared
methane
HITRAN

Access to Document

10.1117/12.621607

PaperAccepted author manuscript, 299 KB
LicenseAccepted author manuscript, 4.01 KB
Extracted textAccepted author manuscript, 38.6 KB

Handle.net

Persistent link

Cite this

@article{061024fd22a641c9abc47cbf6d41076f,

title = "Comparison of spectrally resolved outgoing longwave radiation between 1970 and 2003: The ν4 band of methane",

abstract = "Measurements of spectrally resolved outgoing longwave radiation recorded in 1970, 1997 and 2003 are compared to determine the change in radiative forcing over that period. The changes are shown to be in agreements with that simulated by MODTRAN, a band model, using the known changes in atmospheric temperature and greenhouse gas concentrations when the effects of noise in the observed spectra are considered. The only region where the simulations are unable to reproduce the observations is in the v4 band of methane around 1306cm-1. The methane profiles used to simulate this region of the spectrum are shown to be in good agreement with all available data and the noise levels on the spectra are small. Therefore, it is proposed that the inability to model this region lies in the model formulation. Genln2, a line-by-line model, is shown to give very different results in this particular band to those obtained using MODTRAN. Sensitivity studies show that Genln2 is also not able to fully reproduce the spectrum observed. Errors in the spectroscopic parameters are shown to be smaller than the observed discrepancy and line mixing in methane is suggested as a possible cause of the discrepancy.",

keywords = "outgoing longwave radiation, spectrum, greenhouse gases, simulation, infrared, methane, HITRAN",

author = "JA Griggs and JE Harries",

note = "Rose publication type: Journal article Sponsorship: This work was supported by a NERC studentship. Terms of use: Copyright 2005 Society of Photo-Optical Instrumentation Engineers. This paper was published in Proceedings of SPIE Volume: 5883 and is made available as an electronic reprint (preprint) with permission of SPIE. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. ",

year = "2005",

month = aug,

day = "29",

doi = "10.1117/12.621607",

language = "English",

volume = "5883",

journal = "Proceedings of SPIE",

issn = "0277-786X",

publisher = "Society of Photo-Optical Instrumentation Engineers (SPIE)",

}

TY - JOUR

T1 - Comparison of spectrally resolved outgoing longwave radiation between 1970 and 2003: The ν4 band of methane

AU - Griggs, JA

AU - Harries, JE

N1 - Rose publication type: Journal article Sponsorship: This work was supported by a NERC studentship. Terms of use: Copyright 2005 Society of Photo-Optical Instrumentation Engineers. This paper was published in Proceedings of SPIE Volume: 5883 and is made available as an electronic reprint (preprint) with permission of SPIE. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.

PY - 2005/8/29

Y1 - 2005/8/29

N2 - Measurements of spectrally resolved outgoing longwave radiation recorded in 1970, 1997 and 2003 are compared to determine the change in radiative forcing over that period. The changes are shown to be in agreements with that simulated by MODTRAN, a band model, using the known changes in atmospheric temperature and greenhouse gas concentrations when the effects of noise in the observed spectra are considered. The only region where the simulations are unable to reproduce the observations is in the v4 band of methane around 1306cm-1. The methane profiles used to simulate this region of the spectrum are shown to be in good agreement with all available data and the noise levels on the spectra are small. Therefore, it is proposed that the inability to model this region lies in the model formulation. Genln2, a line-by-line model, is shown to give very different results in this particular band to those obtained using MODTRAN. Sensitivity studies show that Genln2 is also not able to fully reproduce the spectrum observed. Errors in the spectroscopic parameters are shown to be smaller than the observed discrepancy and line mixing in methane is suggested as a possible cause of the discrepancy.

AB - Measurements of spectrally resolved outgoing longwave radiation recorded in 1970, 1997 and 2003 are compared to determine the change in radiative forcing over that period. The changes are shown to be in agreements with that simulated by MODTRAN, a band model, using the known changes in atmospheric temperature and greenhouse gas concentrations when the effects of noise in the observed spectra are considered. The only region where the simulations are unable to reproduce the observations is in the v4 band of methane around 1306cm-1. The methane profiles used to simulate this region of the spectrum are shown to be in good agreement with all available data and the noise levels on the spectra are small. Therefore, it is proposed that the inability to model this region lies in the model formulation. Genln2, a line-by-line model, is shown to give very different results in this particular band to those obtained using MODTRAN. Sensitivity studies show that Genln2 is also not able to fully reproduce the spectrum observed. Errors in the spectroscopic parameters are shown to be smaller than the observed discrepancy and line mixing in methane is suggested as a possible cause of the discrepancy.

KW - outgoing longwave radiation

KW - spectrum

KW - greenhouse gases

KW - simulation

KW - infrared

KW - methane

KW - HITRAN

U2 - 10.1117/12.621607

DO - 10.1117/12.621607

M3 - Article (Academic Journal)

SN - 0277-786X

VL - 5883

JO - Proceedings of SPIE

JF - Proceedings of SPIE

ER -

Comparison of spectrally resolved outgoing longwave radiation between 1970 and 2003: The ν4 band of methane

Abstract

Bibliographical note

Keywords

Access to Document

Handle.net

Fingerprint

Cite this