Very Narrow Band Model Calculations of Atmospheric Fluxes and Cooling Rates

Bernstein, L. S.; Berk, Alexander; Acharya, Prabhat K.; Robertson, David; Anderson, George P.; Chetwynd, James H.; Kimball, L. M.

doi:10.1175/1520-0469(1996)053<2887:vnbmco>2.0.co;2

Cited by 47 publications

(35 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…We take advantage of Ramaswamy et al (2006) Synthetic spectra ranging from 100 to 2500 cm 21 with 1 cm 21 resolution are simulated offline by using a radiative transfer code, MODTRAN version 4 (Bernstein et al 1996), assuming a nonscattering plane-parallel atmosphere (Goody and Yung 1989). The choice of this particular radiative transfer model as well as the configuration is a compromise between speed and spectral resolution.…”

Section: Model and Observation Data A Modelmentioning

confidence: 99%

Evolution and Trend of the Outgoing Longwave Radiation Spectrum

Huang

Ramaswamy

2009

Journal of Climate

View full text Add to dashboard Cite

The variability and change occurring in the outgoing longwave radiation (OLR) spectrum are investigated by using simulations performed with a Geophysical Fluid Dynamics Laboratory coupled atmosphere-oceanland general circulation model. First, the variability in unforced climate (natural variability) is simulated. Then, the change of OLR spectrum due to forced changes in climate is analyzed for a continuous 25-yr time series and for the difference between two time periods (1860s and 2000s). Spectrally resolved radiances have more pronounced and complex changes than broadband fluxes. In some spectral regions, the radiance change is dominated by just one controlling factor (e.g., the window region and CO 2 band center radiances are controlled by surface and stratospheric temperatures, respectively) and well exceeds the natural variability. In some other spectral bands, the radiance change is influenced by multiple and often competing factors (e.g., the water vapor band radiance is influenced by both water vapor concentration and temperature) and, although still detectable against natural variability at certain frequencies, demands stringent requirements (drift less than 0.1 K decade 21 at spectral resolution no less than 1 cm 21 ) of observational platforms. The difference between clear-sky and all-sky radiances in the forced climate problem offers a measure of the change in the cloud radiative effect, but with a substantive dependence on the temperature lapse rate change. These results demonstrate that accurate and continuous observations of the OLR spectrum provide an advantageous means for monitoring the changes in the climate system and a stringent means for validating climate models.

show abstract

Section: Model and Observation Data A Modelmentioning

confidence: 99%

Evolution and Trend of the Outgoing Longwave Radiation Spectrum

Huang

Ramaswamy

2009

Journal of Climate

View full text Add to dashboard Cite

show abstract

“…[1][2][3][4][5][6][7][8] MODTRAN uses a spherically symmetric atmosphere, consisting of homogeneous layers, each of which is characterized by the layer boundary specification of temperature, pressure and atmospheric species concentrations; it uses Snell's law to refract a line-of-sight (LOS). To illustrate the accuracy of the band model transmittance approach, MODTRAN4 and FASCODE transmittances are compared at 5 cm' resolution (FWHM) between 1600 and 2500 nm in Figure 1 .…”

Section: Introductionmentioning

confidence: 99%

MODTRAN4: multiple scattering and bidirectional reflectance distribution function (BRDF) upgrades to MODTRAN

et al. 1999

View full text Add to dashboard Cite

Radiance multiply scattered from clouds and thick aerosols is a significant component in the short wave IR through the visible region ofthe electro-optical (EO) spectrum. In MODTRAN, until very recently, multiple scattering predictions could not vary with the azimuth of the line-of-sight (LOS), although the single scattering component of the radiance did take the azimuthal variation into account. MODTRAN has now been upgraded to incorporate the dependence of multiple scattering (MS) on the azimuth of the LOS. This was accomplished by upgrading the interface between MODTRAN and DISORT, which is used as an MS subroutine in MODTRAN. Results from the upgraded MODTRAN are compared against measurements of radiance in a cloudy sky in the 1.5-2.5 tm region. Furthermore, taking advantage of DISORT, the upgraded version of MODTRAN can accommodate parameterized BRDFs (Bi-Directional Reflectance Distribution Functions) for surfaces. Some results, which demonstrate the new MODTRAN capabilities, are presented. Additionally, MS results from MODTRAN are compared to results obtained from a Monte-Carlo model.

show abstract

“…2a that shows sensitivity of the OLR to idealized distribution of humidity in the free troposphere obtained from computations similar to that of Spencer and Braswell (1997). Radiative computations have been performed as discussed in Roca et al (2005) but with the use of the MODTRAN code (Bernstein et al 1996;Berk et al 2000) instead of a broad-band model. The vertical profile of temperature is a multiyear summer average of Bay of Bengal conditions from ERA-40.…”

mentioning

confidence: 99%

Tropical and Extra-Tropical Influences on the Distribution of Free Tropospheric Humidity Over the Intertropical Belt

et al. 2012

View full text Add to dashboard Cite

International audienceFree tropospheric humidity (FTH) is a key parameter of the radiation budget of the Earth. In particular, its distribution over the intertropical belt has been identified as an important contributor to the water vapour feedback. Idealized radiative transfer computations are performed to underscore the need to consider the whole probability distribution function (PDF) rather than the arithmetical mean of the FTH. The analysis confirmed the overwhelming role of the dry end of the PDF in the radiative perturbation of the top of atmosphere longwave budget. The physical and dynamical processes responsible for the maintenance of this dry part of the FTH distribution are reviewed, and the lateral mixing between the tropics and the extra-tropics is revealed as a major element of the dry air dynamics. The evolution of this lateral mixing in the framework of the global warming is discussed, and perspectives of work are listed as a mean of a conclusion

show abstract

Very Narrow Band Model Calculations of Atmospheric Fluxes and Cooling Rates

Cited by 47 publications

References 0 publications

Evolution and Trend of the Outgoing Longwave Radiation Spectrum

Evolution and Trend of the Outgoing Longwave Radiation Spectrum

MODTRAN4: multiple scattering and bidirectional reflectance distribution function (BRDF) upgrades to MODTRAN

Tropical and Extra-Tropical Influences on the Distribution of Free Tropospheric Humidity Over the Intertropical Belt

Contact Info

Product

Resources

About