Two‐ and four‐stream optical properties for water clouds and solar wavelengths

Dobbie, J. S.; Li, Jiangnan; Chýlek, Petr

doi:10.1029/1998jd200039

Cited by 68 publications

(57 citation statements)

References 15 publications

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“…With the cloud water contents and effective particles sizes, the cloud optical properties for each band in the CKD are computed for liquid cloud particles at solar (Dobbie, Li, and Chýlek, 1999) and infrared (Lindner and Li, 2000) wavenumbers and for ice cloud particles at solar (Fu, 1996) and infrared (Fu, Yang, and Sun, 1998) wavenumbers.…”

Section: Cloud Microphysicsmentioning

confidence: 99%

The Canadian Fourth Generation Atmospheric Global Climate Model (CanAM4). Part I: Representation of Physical Processes

et al. 2013

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The Canadian Centre for Climate Modelling and Analysis (CCCma) has developed the fourth generation of the Canadian Atmospheric Global Climate Model (CanAM4). The new model includes substantially modified physical parameterizations compared to its predecessor. In particular, the treatment of clouds, cloud radiative effects, and precipitation has been modified. Aerosol direct and indirect effects are calculated based on a bulk aerosol scheme. Simulation results for present-day global climate are analyzed, with a focus on cloud radiative effects and precipitation. Good overall agreement is found between climatological mean short-and longwave cloud radiative effects and observations from the Clouds and Earth's Radiant Energy System (CERES) experiment. An analysis of the responses of cloud radiative effects to variations in climate will be presented in a companion paper.RÉSUMÉ [Traduit par la rédaction] Le Centre canadien de la modélisation et de l'analyse climatique (CCmaC) a mis au point la quatrième génération du modèle canadien de circulation générale de l'atmosphère (CanAM4). Le nouveau modèle comprend des paramétrisations physiques passablement modifiées comparativement à son prédé-cesseur. En particulier, le traitement des nuages, des effets radiatifs des nuages et des précipitations a été modifié. Les effets directs et indirects des aérosols sont calculés à l'aide d'un schéma d'aérosols en bloc. Nous analysons des résultats de simulation pour le climat général du jour présent en mettant l'accent sur les effets radiatifs des nuages et les précipitations. Nous trouvons un bon accord général entre la moyenne climatologique des effets radiatifs des nuages pour les courtes et les grandes longueurs d'onde et les observations de l'expérience CERES (Clouds and Earth's Radiant Energy System). Une analyse de la réponse des effets radiatifs des nuages aux variations du climat sera présentée dans un article connexe.

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Section: Cloud Microphysicsmentioning

confidence: 99%

The Canadian Fourth Generation Atmospheric Global Climate Model (CanAM4). Part I: Representation of Physical Processes

et al. 2013

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“…Gaseous transmittances (H 2 O, CO 2 and O 3 for SW; H 2 O, CO 2 , O 3 , CH 4 , N 2 O, CFCl 3 and CF 2 Cl 2 for LW) were computed using the correlated k-distribution method with 31 quadrature points in cumulative probability space for SW and 46 for LW (Scinocca et al, 2008). Optical properties for liquid droplets (Dobbie et al, 1999;Lindner and Li, 2000) and ice crystals (Fu, 1996;Fu et al, 1998) were resolved into four SW bands and nine LW bands. Aerosols were neglected.…”

Section: D Radiative Transfer For Constructed Domainsmentioning

confidence: 99%

A 3D cloud‐construction algorithm for the EarthCARE satellite mission

Barker

Jerg

Wehr

et al. 2011

Quart J Royal Meteoro Soc

144

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† The contribution of H. W. Barker to this article was prepared as part of his official duties as a Canadian government employee This article presents and assesses an algorithm that constructs 3D distributions of cloud from passive satellite imagery and collocated 2D nadir profiles of cloud properties inferred synergistically from lidar, cloud radar and imager data. It effectively widens the active-passive retrieved cross-section (RXS) of cloud properties, thereby enabling computation of radiative fluxes and radiances that can be compared with measured values in an attempt to perform radiative closure experiments that aim to assess the RXS. For this introductory study, A-train data were used to verify the scene-construction algorithm and only 1D radiative transfer calculations were performed.The construction algorithm fills off-RXS recipient pixels by computing sums of squared differences (a cost function F) between their spectral radiances and those of potential donor pixels/columns on the RXS. Of the RXS pixels with F lower than a certain value, the one with the smallest Euclidean distance to the recipient pixel is designated as the donor, and its retrieved cloud properties and other attributes such as 1D radiative heating rates are consigned to the recipient. It is shown that both the RXS itself and Moderate Resolution Imaging Spectroradiometer (MODIS) imagery can be reconstructed extremely well using just visible and thermal infrared channels. Suitable donors usually lie within 10 km of the recipient. RXSs and their associated radiative heating profiles are reconstructed best for extensive planar clouds and less reliably for broken convective clouds. Domain-average 1D broadband radiative fluxes at the top of the atmosphere (TOA) for (21 km) 2 domains constructed from MODIS, CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) data agree well with coincidental values derived from Clouds and the Earth's Radiant Energy System (CERES) radiances: differences between modelled and measured reflected shortwave fluxes are within ±10 W m −2 for ∼35% of the several hundred domains constructed for eight orbits. Correspondingly, for outgoing longwave radiation ∼65% are within ±10 W m −2 .

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“…-Aerosol and cloud parameterisations (Shettle and Fenn, 1979;Stephens, 1979;Slingo, 1989;Hu and Stamnes, 1993;Dobbie et al, 1999;Lindner and Li, 2000).…”

Section: The Applied Modelmentioning

confidence: 99%

On realistic size equivalence and shape of spheroidal Saharan mineral dust particles applied in solar and thermal radiative transfer calculations

Otto

Trautmann²,

Wendisch

2011

Atmos. Chem. Phys.

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Abstract. Realistic size equivalence and shape of Saharan mineral dust particles are derived from in-situ particle, lidar and sun photometer measurements during SAMUM-1 in Morocco (19 May 2006), dealing with measured sizeand altitude-resolved axis ratio distributions of assumed spheroidal model particles. The data were applied in optical property, radiative effect, forcing and heating effect simulations to quantify the realistic impact of particle nonsphericity. It turned out that volume-to-surface equivalent spheroids with prolate shape are most realistic: particle nonsphericity only slightly affects single scattering albedo and asymmetry parameter but may enhance extinction coefficient by up to 10 %. At the bottom of the atmosphere (BOA) the Saharan mineral dust always leads to a loss of solar radiation, while the sign of the forcing at the top of the atmosphere (TOA) depends on surface albedo: solar cooling/warming over a mean ocean/land surface. In the thermal spectral range the dust inhibits the emission of radiation to space and warms the BOA. The most realistic case of particle non-sphericity causes changes of total (solar plus thermal) forcing by 55/5 % at the TOA over ocean/land and 15 % at the BOA over both land and ocean and enhances total radiative heating within the dust plume by up to 20 %. Large dust particles significantly contribute to all the radiative effects reported. They strongly enhance the absorbing properties and forward scattering in the solar and increase predominantly, e.g., the total TOA forcing of the dust over land.

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Two‐ and four‐stream optical properties for water clouds and solar wavelengths

Cited by 68 publications

References 15 publications

The Canadian Fourth Generation Atmospheric Global Climate Model (CanAM4). Part I: Representation of Physical Processes

The Canadian Fourth Generation Atmospheric Global Climate Model (CanAM4). Part I: Representation of Physical Processes

A 3D cloud‐construction algorithm for the EarthCARE satellite mission

On realistic size equivalence and shape of spheroidal Saharan mineral dust particles applied in solar and thermal radiative transfer calculations

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