Clear‐sky Atmospheric Radiative Transfer: A Model Intercomparison for Shortwave Irradiances

2009 ◽  
Author(s):  
P. Wang ◽  
W. H. Knap ◽  
P. Kuipers Munneke ◽  
P. Stammes
Keyword(s):  
Radiative Transfer ◽  
Model Intercomparison ◽  
Clear Sky ◽  
Atmospheric Radiative Transfer

scholarly journals Full-Spectrum Correlated-k Distribution for Shortwave Atmospheric Radiative Transfer

2004 ◽  
Vol 61 (21) ◽  
pp. 2588-2601 ◽  
Author(s):  
Daniel T. Pawlak ◽  
Eugene E. Clothiaux ◽  
Michael F. Modest ◽  
Jason N. S. Cole
Keyword(s):  
Radiative Transfer ◽  
Source Function ◽  
Computation Time ◽  
Spectral Interval ◽  
Heating Rates ◽  
Full Spectrum ◽  
Solar Source ◽  
Clear Sky ◽  
Spectral Bands ◽  
Atmospheric Radiative Transfer

Abstract The full-spectrum correlated k-distribution (FSCK) method, originally developed for applications in combustion systems, is adapted for use in shortwave atmospheric radiative transfer. By weighting k distributions by the solar source function, the FSCK method eliminates the requirement that the Planck function be constant over a spectral interval. As a consequence, integration may be carried out across the full spectrum as long as the assumption of correlation from one atmospheric level to the next remains valid. Problems with the lack of correlation across the full spectrum are removed by partitioning the spectrum at a wavelength of 0.68 μm into two bands. The resulting two-band approach in the FSCK formalism produces broadband rms clear-sky flux and heating rate errors less than 1% and 6%, respectively, relative to monochromatic calculations and requires only 15 quadrature points per layer, which represents a 60%–90% reduction in computation time relative to other models currently in use. An evaluation of fluxes calculated by the FSCK method in cases with idealized clouds demonstrates that gray cloud scattering in two spectral bands is sufficient to reproduce line-by-line generated fluxes. Two different approaches for modeling absorption by cloud drops were also examined. Explicitly including nongray cloud absorption in solar source function-weighted k distributions results in realistic in-cloud heating rates, although in-cloud heating rates were underpredicted by approximately 8%–12% as compared to line-by-line results. A gray cloud absorption parameter chosen to fit line-by-line results optimally for one cloud or atmospheric profile but applied to different cloud combinations or profiles, also closely approximated line-by-line heating rates.

scholarly journals Intercomparison of general purpose clear sky atmospheric radiative transfer models for the millimeter/submillimeter spectral range

Radio Science ◽  
2005 ◽  
Vol 40 (1) ◽  
pp. n/a-n/a ◽  
Author(s):  
C. Melsheimer ◽  
C. Verdes ◽  
S. A. Buehler ◽  
C. Emde ◽  
P. Eriksson ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Spectral Range ◽  
General Purpose ◽  
Clear Sky ◽  
Radiative Transfer Models ◽  
Atmospheric Radiative Transfer ◽  
Transfer Models

scholarly journals Aerosol direct radiative forcing during Sahara dust intrusions in the Central Mediterranean

2010 ◽  
Vol 10 (8) ◽  
pp. 20673-20727
Author(s):  
M. R. Perrone ◽  
A. Bergamo ◽  
V. Bellantone
Keyword(s):  
Optical Properties ◽  
Radiative Transfer ◽  
Spectral Range ◽  
Mediterranean Basin ◽  
Transfer Model ◽  
Clear Sky ◽  
Fine Mode ◽  
The Mediterranean ◽  
The Mediterranean Basin ◽  
Sahara Dust

Abstract. The clear-sky, instantaneous Direct Radiative Effect (DRE) by all and anthropogenic particles is calculated during Sahara dust intrusions in the Mediterranean basin, to evaluate the role of anthropogenic particle's radiative effects and to obtain a better estimate of the DRE by desert dust. The clear-sky aerosol DRE is calculated by a two stream radiative transfer model in the solar (0.3–4 μm) and infrared (4–200 μm) spectral range, at the top of the atmosphere (ToA) and at the Earth's surface (sfc). Aerosol optical properties by AERONET sun-sky photometer measurements and aerosol vertical profiles by EARLINET lidar measurements, both performed at Lecce (40.33° N, 18.10° E) during Sahara dust intrusions occurred from 2003 to 2006 year, are used to perform radiative transfer simulations. Instantaneous values at 0.44 μm of the real (n) and imaginary (k) refractive index and of the of aerosol optical depth (AOD) vary within the 1.33–1.55, 0.0037–0.014, and 0.2–0.7 range, respectively during the analyzed dust outbreaks. Fine mode particles contribute from 34% to 85% to the AOD by all particles. The complex atmospheric chemistry of the Mediterranean basin that is also influenced by regional and long-range transported emissions from continental Europe and the dependence of dust optical properties on soil properties of source regions and transport pathways, are responsible for the high variability of n, k, and AOD values and of the fine mode particle contribution. Instantaneous all-wave (solar+infrared) DREs that are negative as a consequence of the cooling effect by aerosol particles, span the – (32–10) Wm−2 and the – (44–20) Wm−2 range at the ToA and surface, respectively. The instantaneous all-wave DRE by anthropogenic particles that is negative, varies within – (13–7) Wm−2 and – (18–11) Wm−2 at the ToA and surface, respectively. It represents from 41% up to 89% and from 32% up to 67% of the all-wave DRE by all particles at the ToA and surface, respectively during the analysed dust outbreaks. A linear relationship to calculate the DRE by natural particles in the solar and infrared spectral range is provided.

An upgraded combined atmospheric radiative transfer CART2(Invited)

2020 ◽  
Vol 49 (7) ◽  
pp. 20201024
Author(s):  
魏合理 Heli Wei ◽  
戴聪明 Congming Dai ◽  
武鹏飞 Pengfei Wu ◽  
唐超礼 Chaoli Tang ◽  
赵凤美 Fengmei Zhao ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Atmospheric Radiative Transfer
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