Robert Gamache - Profile on Academia.edu (original) (raw)
Papers by Robert Gamache
Molecular Physics, Jul 30, 2010
With the modified Robert-Bonamy (RB) formalism, the halfwidth is given by The integrand of ... more With the modified Robert-Bonamy (RB) formalism, the halfwidth is given by The integrand of is Usually, S 2 consists of three terms S 2,outer,I , S 2,outer,f , and S 2,middle . For example, S 2,outer,I is given by In order to consider more realistic potentials, it is necessary to include a short range atom-atom model V atom-atom (t) () 2 2 2 2 2 2 Re ( ) (1 ).
Reduced matrix elements for CH4 from ab initio wavefunctions for line shape calculations
Line shape parameters for nu3 transitions of CH4
HAL (Le Centre pour la Communication Scientifique Directe), Jun 15, 2008
Communication P6
Total internal partition sums for the HITRAN2020 database
Journal of Quantitative Spectroscopy and Radiative Transfer, 2021
Corrigendum to "Measurement and computations for temperature dependences of self-broadened carbon dioxide transitions in the 30012←00001 and 30013←00001 bands" [J. Quant. Spectrosc. Radiat. Transf., 111 (9) (2010) 1065–1079]
Journal of Quantitative Spectroscopy and Radiative Transfer, 2015
Journal of Molecular Spectroscopy, 2016
Radio Science, 1989
The ionosphere is known to be a dispersive medium. Additionally, for a fixed ground distance inan... more The ionosphere is known to be a dispersive medium. Additionally, for a fixed ground distance inan oblique propagation geometry, the ray of each Fourier component of a pulse follows its own path in a phenomenon known as frequency splitting. As a consequence of these two factors distortion results. Under the approximation of a quadratic phase channel, this distortion is most conveniently characterized by a quantity, known as the dispersive bandwidth. Formulas for the dispersive bandwidth have been derived both for the linear layer and the parabolic layer and are given without showing derivations. A technique has been developed to analyze the vertical ionogram for dispersive bandwidth. This technique has been applied to several days of digital ionosonde data. The resulting values of dispersive bandwidth are reasonable and plotted over a diurnal cycle. Such a technique should be further developed as a step toward eventual application to ionospheric informatics.
Proceedings of the 70th International Symposium on Molecular Spectroscopy, 2015
For SO 2 atmospheric characterization in Venus and other Exoplanetary environments, recently we p... more For SO 2 atmospheric characterization in Venus and other Exoplanetary environments, recently we presented Ames-296K line lists for 626 (upgraded) and other 4 symmetric isotopologues: 636, 646, 666 and 828. For CO 2 , we reported Ames-296K (1E-42 cm/molecule) and Ames-1000K (1E-36 cm/molecule) IR line lists up to E'=18000 cm -1 for 13 CO 2
Journal of Quantitative Spectroscopy and Radiative Transfer, 2015
We present CDSD-296 a version of the Carbon Dioxide Spectroscopic Databank aimed at processing si... more We present CDSD-296 a version of the Carbon Dioxide Spectroscopic Databank aimed at processing signals from the satellite based sensors. The databank contains line parameters (positions, intensities as well as HITRAN air-and self-broadened halfwidths and coefficients of temperature dependence of air-broadened halfwidths) of the four most abundant isotopic species of CO 2 . The reference temperature is T ref =296 K, the intensity cutoff is I cut =10 -28 cm -1 /(molecule cm -2 ) and the spectral range is 405-12784 cm -1 . The databank was generated within the framework of the method of effective operators and based on the global fittings of parameters of the models to observed data collected from the literature. Calculated line positions were systematically replaced where possible by the differences between experimental term values derived from recalibrated observed line positions with the help of the combination Ritz principle. The databank includes statistically justified confidence intervals for each line position and intensity.
High-latitude ionospheric radio studies. Final report, 3 May 1983-30 September 1986
Structure and dynamics of the ionosphere are explored under this contract by digital high-frequen... more Structure and dynamics of the ionosphere are explored under this contract by digital high-frequency sounding techniques. The research emphasizes the investigation of the auroral and subauroral ionosphere, but also includes studies on the polar-cap and mid-latitude ionosphere.
Journal of Quantitative Spectroscopy and Radiative Transfer, 2005
Since 1998, we have developed two balloonborne diode laser spectrometers, SDLA and micro-SDLA, to... more Since 1998, we have developed two balloonborne diode laser spectrometers, SDLA and micro-SDLA, to yield in situ concentration data of H 2 O in the middle atmosphere by absorption spectroscopy in the 1.39mm spectral range. In this paper, we revisit the molecular parameters, line intensities and pressurebroadening coefficients, for several lines of the n 1 +n 3 and 2n 1 bands, which are useful for the monitoring of atmospheric H 2 O. The new values are thoroughly compared to existing molecular database and previous determinations. Calculations are performed to yield the pressure-effect coefficients: the theoretical model is described and the ab initio predictions are compared to laboratory measurements achieved with a laser diode spectrometer. The improvement in the H 2 O monitoring obtained with the new set of molecular data is evaluated directly from vertical H 2 O concentration profiles.
Journal of Geophysical Research, 1994
This paper compares the observed behavior of the Fe layer of the ionosphere at Millstone Hill and... more This paper compares the observed behavior of the Fe layer of the ionosphere at Millstone Hill and Hobart with calculations from the field line interhemispheric plasma (FLIP) model for solar maximum, solstice conditions in 1990. During the study period the daily F10.? index varied by more than a factor of 2 (123 to 280), but the 81-day mean F10.? (F10.?A) was almost constant near 190. Calculations were performed with and without the effects of vibrationally excited N2 (N]) which affects the loss rate of atomic oxygen ions. In the case without N] there is generally good agreement between the model and measurement for the daytime, peak density of the F region (NmFe). Both the model and the measurement show a strong seasonal anomaly with the winter noon densities a factor of 3 to 4 greater than the summer noon densities at Millstone Hill and a factor of 2 greater at Hobart. The seasonal anomaly in the model is caused by changes in the neutral composition as given by the mass spectrometer and incoherent scatter (MSIS) 86 neutral density model. There is generally little or no increase in the observed noon NmFe as a function of daily F10.7 except at Millstone Hill in winter. In May-July, where the measured NmFe shows least dependence on daily F10.?, there is excellent agreement between the model and data. The modeled NmFe is about 30% less than the measured values at Millstone Hill at the December solstice, but both model and data increase with increasing daily F10.? index. At Hobart, on the other hand, the model densities are greater than or comparable to the measured densities for the December solstice. This suggests that the differences between model and data are not due to the incorrect solar EUV flux. The effect of including N] is to worsen the agreement between model and data at Millstone Hill by reducing the summer densities from good agreement to 40% below the data. In winter the N• effects are much smaller, and the densities are reduced by only 10%. While N] worsens the model-data comparison at Millstone Hill, it does bring the model seasonal density ratio into better agreement with the data and also improves the agreement at Hobart. Although the 1990 daytime ionosphere can be well modeled without N], it may still be important for high levels of solar and magnetic activity. There is a very close relationship between the height at which peak density occurs hmFe variation and the NmFe variation with F10.? in summer at Millstone Hill. In contrast to the generally good agreement between model and data at noon, the model badly underestimates the density at night at Millstone Hill at all seasons. At Hobart the model reproduces the nighttime density variations well in both winter and summer. The international reference ionosphere (IRI) model generally provides a good representation of the average behavior of noon NmFe and hmFe but because the data show a lot of day-to-day variability, there are often large differences. The FLIP model is able to reproduce this variability when hmFe is specified. The IRI model peak densities are better than the FLIP densities at night, but the IRI model does not represent the Millstone Hill summer data very well at night in 1990.
Statistical studies of the N(h) profile of the ionosphere using automatically scaled digital ionograms
Advances in Space Research, 1991
ABSTRACT The relationships between ionospheric profile parameters are studied by examining 6000 D... more ABSTRACT The relationships between ionospheric profile parameters are studied by examining 6000 Digisonde 256 ionograms that are automatically scaled with the Artist program. Using basic models of the ionosphere, estimates of the profile parameters are calculated for comparison with the Digisonde data. The formula for hmF2 by Dudeney (1983) is examined with respect to ionospheric data, and the method is found to be very accurate for the midlatitude ionosphere. Examination of the height at half the peak density reveals the inadequacy of Guliaeva's value for the parameter. A distinct correlation is noted between the semithickness of the F2 layer and the value of hmF2. Large-scale analyses of the ionospheric structure can be facilitated by combining automatic scaling techniques to digital vertical-incidence ionosonde data.
Molecular Physics, Jul 30, 2010
With the modified Robert-Bonamy (RB) formalism, the halfwidth is given by The integrand of ... more With the modified Robert-Bonamy (RB) formalism, the halfwidth is given by The integrand of is Usually, S 2 consists of three terms S 2,outer,I , S 2,outer,f , and S 2,middle . For example, S 2,outer,I is given by In order to consider more realistic potentials, it is necessary to include a short range atom-atom model V atom-atom (t) () 2 2 2 2 2 2 Re ( ) (1 ).
Reduced matrix elements for CH4 from ab initio wavefunctions for line shape calculations
Line shape parameters for nu3 transitions of CH4
HAL (Le Centre pour la Communication Scientifique Directe), Jun 15, 2008
Communication P6
Total internal partition sums for the HITRAN2020 database
Journal of Quantitative Spectroscopy and Radiative Transfer, 2021
Corrigendum to "Measurement and computations for temperature dependences of self-broadened carbon dioxide transitions in the 30012←00001 and 30013←00001 bands" [J. Quant. Spectrosc. Radiat. Transf., 111 (9) (2010) 1065–1079]
Journal of Quantitative Spectroscopy and Radiative Transfer, 2015
Journal of Molecular Spectroscopy, 2016
Radio Science, 1989
The ionosphere is known to be a dispersive medium. Additionally, for a fixed ground distance inan... more The ionosphere is known to be a dispersive medium. Additionally, for a fixed ground distance inan oblique propagation geometry, the ray of each Fourier component of a pulse follows its own path in a phenomenon known as frequency splitting. As a consequence of these two factors distortion results. Under the approximation of a quadratic phase channel, this distortion is most conveniently characterized by a quantity, known as the dispersive bandwidth. Formulas for the dispersive bandwidth have been derived both for the linear layer and the parabolic layer and are given without showing derivations. A technique has been developed to analyze the vertical ionogram for dispersive bandwidth. This technique has been applied to several days of digital ionosonde data. The resulting values of dispersive bandwidth are reasonable and plotted over a diurnal cycle. Such a technique should be further developed as a step toward eventual application to ionospheric informatics.
Proceedings of the 70th International Symposium on Molecular Spectroscopy, 2015
For SO 2 atmospheric characterization in Venus and other Exoplanetary environments, recently we p... more For SO 2 atmospheric characterization in Venus and other Exoplanetary environments, recently we presented Ames-296K line lists for 626 (upgraded) and other 4 symmetric isotopologues: 636, 646, 666 and 828. For CO 2 , we reported Ames-296K (1E-42 cm/molecule) and Ames-1000K (1E-36 cm/molecule) IR line lists up to E'=18000 cm -1 for 13 CO 2
Journal of Quantitative Spectroscopy and Radiative Transfer, 2015
We present CDSD-296 a version of the Carbon Dioxide Spectroscopic Databank aimed at processing si... more We present CDSD-296 a version of the Carbon Dioxide Spectroscopic Databank aimed at processing signals from the satellite based sensors. The databank contains line parameters (positions, intensities as well as HITRAN air-and self-broadened halfwidths and coefficients of temperature dependence of air-broadened halfwidths) of the four most abundant isotopic species of CO 2 . The reference temperature is T ref =296 K, the intensity cutoff is I cut =10 -28 cm -1 /(molecule cm -2 ) and the spectral range is 405-12784 cm -1 . The databank was generated within the framework of the method of effective operators and based on the global fittings of parameters of the models to observed data collected from the literature. Calculated line positions were systematically replaced where possible by the differences between experimental term values derived from recalibrated observed line positions with the help of the combination Ritz principle. The databank includes statistically justified confidence intervals for each line position and intensity.
High-latitude ionospheric radio studies. Final report, 3 May 1983-30 September 1986
Structure and dynamics of the ionosphere are explored under this contract by digital high-frequen... more Structure and dynamics of the ionosphere are explored under this contract by digital high-frequency sounding techniques. The research emphasizes the investigation of the auroral and subauroral ionosphere, but also includes studies on the polar-cap and mid-latitude ionosphere.
Journal of Quantitative Spectroscopy and Radiative Transfer, 2005
Since 1998, we have developed two balloonborne diode laser spectrometers, SDLA and micro-SDLA, to... more Since 1998, we have developed two balloonborne diode laser spectrometers, SDLA and micro-SDLA, to yield in situ concentration data of H 2 O in the middle atmosphere by absorption spectroscopy in the 1.39mm spectral range. In this paper, we revisit the molecular parameters, line intensities and pressurebroadening coefficients, for several lines of the n 1 +n 3 and 2n 1 bands, which are useful for the monitoring of atmospheric H 2 O. The new values are thoroughly compared to existing molecular database and previous determinations. Calculations are performed to yield the pressure-effect coefficients: the theoretical model is described and the ab initio predictions are compared to laboratory measurements achieved with a laser diode spectrometer. The improvement in the H 2 O monitoring obtained with the new set of molecular data is evaluated directly from vertical H 2 O concentration profiles.
Journal of Geophysical Research, 1994
This paper compares the observed behavior of the Fe layer of the ionosphere at Millstone Hill and... more This paper compares the observed behavior of the Fe layer of the ionosphere at Millstone Hill and Hobart with calculations from the field line interhemispheric plasma (FLIP) model for solar maximum, solstice conditions in 1990. During the study period the daily F10.? index varied by more than a factor of 2 (123 to 280), but the 81-day mean F10.? (F10.?A) was almost constant near 190. Calculations were performed with and without the effects of vibrationally excited N2 (N]) which affects the loss rate of atomic oxygen ions. In the case without N] there is generally good agreement between the model and measurement for the daytime, peak density of the F region (NmFe). Both the model and the measurement show a strong seasonal anomaly with the winter noon densities a factor of 3 to 4 greater than the summer noon densities at Millstone Hill and a factor of 2 greater at Hobart. The seasonal anomaly in the model is caused by changes in the neutral composition as given by the mass spectrometer and incoherent scatter (MSIS) 86 neutral density model. There is generally little or no increase in the observed noon NmFe as a function of daily F10.7 except at Millstone Hill in winter. In May-July, where the measured NmFe shows least dependence on daily F10.?, there is excellent agreement between the model and data. The modeled NmFe is about 30% less than the measured values at Millstone Hill at the December solstice, but both model and data increase with increasing daily F10.? index. At Hobart, on the other hand, the model densities are greater than or comparable to the measured densities for the December solstice. This suggests that the differences between model and data are not due to the incorrect solar EUV flux. The effect of including N] is to worsen the agreement between model and data at Millstone Hill by reducing the summer densities from good agreement to 40% below the data. In winter the N• effects are much smaller, and the densities are reduced by only 10%. While N] worsens the model-data comparison at Millstone Hill, it does bring the model seasonal density ratio into better agreement with the data and also improves the agreement at Hobart. Although the 1990 daytime ionosphere can be well modeled without N], it may still be important for high levels of solar and magnetic activity. There is a very close relationship between the height at which peak density occurs hmFe variation and the NmFe variation with F10.? in summer at Millstone Hill. In contrast to the generally good agreement between model and data at noon, the model badly underestimates the density at night at Millstone Hill at all seasons. At Hobart the model reproduces the nighttime density variations well in both winter and summer. The international reference ionosphere (IRI) model generally provides a good representation of the average behavior of noon NmFe and hmFe but because the data show a lot of day-to-day variability, there are often large differences. The FLIP model is able to reproduce this variability when hmFe is specified. The IRI model peak densities are better than the FLIP densities at night, but the IRI model does not represent the Millstone Hill summer data very well at night in 1990.
Statistical studies of the N(h) profile of the ionosphere using automatically scaled digital ionograms
Advances in Space Research, 1991
ABSTRACT The relationships between ionospheric profile parameters are studied by examining 6000 D... more ABSTRACT The relationships between ionospheric profile parameters are studied by examining 6000 Digisonde 256 ionograms that are automatically scaled with the Artist program. Using basic models of the ionosphere, estimates of the profile parameters are calculated for comparison with the Digisonde data. The formula for hmF2 by Dudeney (1983) is examined with respect to ionospheric data, and the method is found to be very accurate for the midlatitude ionosphere. Examination of the height at half the peak density reveals the inadequacy of Guliaeva's value for the parameter. A distinct correlation is noted between the semithickness of the F2 layer and the value of hmF2. Large-scale analyses of the ionospheric structure can be facilitated by combining automatic scaling techniques to digital vertical-incidence ionosonde data.