Infrared Continuum Absorption by Atmospheric Water Vapor in the 8-12- Micrometer Window

Roberts, Rita; Biberman, L. M.; Selby, John E.

doi:10.21236/ada025377

Cited by 46 publications

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“…The Goody random-band model is adopted for water vapour, the Malkmus model for carbon dioxide and ozone, and the CurtisGodson method is used for line pressure broadening along vertical paths. The Roberts et al (1976) scheme (augmented with foreign-broadened contribution) was considered sufficient for the very important water-vapour continuum effect in the present study, which concentrates on the BL, although the more comprehensive Clough et al (1992) continuum scheme is recommended for the upper troposphere.…”

Section: The Abl Modelmentioning

confidence: 99%

Radiative and turbulent heating rates in the clear‐air boundary layer

Savijärvi

2006

Quart J Royal Meteoro Soc

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SUMMARYThe diurnal evolution of a clear-sky midlatitude summertime boundary layer (BL) was studied using a column model over smooth and homogeneous land, subject to weak, moderate, and strong winds. The highresolution BL model (lowest point at 30 cm) was equipped with an adequate turbulence scheme and a narrow-band long-wave (LW) radiation scheme, the latter validated using data from the International Comparison of Radiation Codes in Climate Models (ICRCCM).In off-line ICRCCM experiments, ground emissivity ε < 1 led to extra LW cooling of air near the surface compared to ε = 1. However, much stronger LW cooling at heights of 1-3 m, and warming below 1 m, was obtained by setting the ground colder than air at screen height, a typical condition during clear nights. Conversely, a warm surface anomaly typical of sunny days leads to strong LW warming at 1-3 m, with LW cooling just above the ground. These ground temperature anomalies dominated the LW heating/cooling patterns at heights of up to 3-4 m, perhaps explaining controversies in the observed LW flux divergences close to the ground.Interactive model results indicate that the middle part of a windy clear-air nocturnal BL (NBL) is dominated by turbulent cooling, while the upper and lower NBL is dominated by LW cooling. Below about 1 m, a fourth layer is formed with LW warming and turbulent cooling, in agreement with the off-line experiments. When the surface winds fall below about 1-1.5 m s −1 LW cooling dominates in the whole NBL, except very near the surface. In these light wind conditions the Monin-Obukhov theory should be revised to include radiative effects.In clear-air daytime conditions strong convective BL heating dominates over weak LW cooling except at 1-3 m heights where the cooler air absorbs the thermal emission of the hot ground. The subsequent LW warming of the superadiabatic surface layer appears to be strong enough to induce local turbulent cooling (despite the hot surface) in an 'hour glass' pattern independently of wind speed, such that the total diabatic heating rate remains nearly constant with height.

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Section: The Abl Modelmentioning

confidence: 99%

Radiative and turbulent heating rates in the clear‐air boundary layer

Savijärvi

2006

Quart J Royal Meteoro Soc

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“…The values of the absorption coefficient were taken from Robert et al (1976). Since the surface emissivity of sea water is a function of incident angle, the effect is also taken into consideration using the table calculated by Masuda et al (1988).…”

Section: Sst=tbb11+1811(tbb11-tbb12)+0671 (2)mentioning

confidence: 99%

A Case Study of the Mesoscale Distribution of Precipitable Water Using the Split-Window Data from a NOAA Satellite

Iwasaki

1994

Journal of the Meteorological Society of Japan

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“…Photolysis Reactions Band model parameters for the water vapor rotation and vibration-rotation bands, the 15 #m CO2 bands, and the O 3 9.6 #m band are taken directly from Ramanathan's work. We have, however, modified the H20 continuum formulation to reflect the results determined by Roberts et al [1976] with respect to the frequency and temperature dependencies of the H20 continuum absorption coefficients. The temperature dependence has been incorporated by simply redefining the water vapor absorber amount to include this variation.…”

Section: For the 2 X •Bn2o And 2 X •Bn2 O + 2 X •Bco Simulationsmentioning

confidence: 99%

On the relationship between the greenhouse effect, atmospheric photochemistry, and species distribution

Callis¹,

Natarajan

Boughner

1983

J. Geophys. Res.

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A radiative‐convective‐photochemical model that extends from 0 to 53 km is used to examine the effect on atmospheric constituents and thermal structure of changes in the atmospheric levels of CO2, CFM's, CO, N2O, and combinations of these species. Calculations were carried out for two reference atmospheres, one with high (HINOX) and one with low (LONOX) levels of NOx. The HINOX atmosphere has a vertical distribution of NOx similar to that resulting from recently published measurements. Such a distribution requires an unrealistically large value for the integrated tropospheric source of NOx. This suggests that the HINOX profile, and the measurements from which it was drawn, are more characteristic of contaminated, rather than clean, air masses. The HINOX troposphere provides a net photochemical source of O3 and is not greatly sensitive to downward transport of O3 from the stratosphere. The LONOX troposphere is a photochemical sink for O3 and, as a result, is sensitive to such variations in downward transport. Results of this study suggest that (1) infrared opacity changes due to CO2 and CFM increases can cause significant changes in tropospheric O3, OH, CH4, CO, and other species through changes in tropospheric water vapor; (2) perturbation or sensitivity studies conducted with tropospheric photochemical models may be subject to significant errors due to the absence of modulating effects provided by the stratosphere; (3) the response to given perturbations is significantly dependent upon the tropospheric NOx distribution present in the model; (4) CO2 growth rates must be included in the calculation of CFM‐O3 time scenarios and must account for surface temperature changes, especially in the steady state; and (5) that thermal or chemical perturbations introduce a variety of coupling or interactive mechanisms which are significant and which may provide compensating effects.

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Infrared Continuum Absorption by Atmospheric Water Vapor in the 8-12- Micrometer Window

Cited by 46 publications

References 0 publications

Radiative and turbulent heating rates in the clear‐air boundary layer

Radiative and turbulent heating rates in the clear‐air boundary layer

A Case Study of the Mesoscale Distribution of Precipitable Water Using the Split-Window Data from a NOAA Satellite

On the relationship between the greenhouse effect, atmospheric photochemistry, and species distribution

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