Parameterization of Atmospheric Radiative Transfer. Part I: Validity of Simple Models

Stephens, Graeme L.; Gabriel, Philip; Partain, Philip T.

doi:10.1175/1520-0469(2001)058<3391:poartp>2.0.co;2

Cited by 86 publications

(71 citation statements)

References 27 publications

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“…The code uses the BUGSrad radiative transfer model (Stephens et al, 2001) in conjunction with the input cloud and aerosol properties derived from ORAC. BUGSrad is based on the two-stream approximation and correlated-k distribution methods of atmospheric radiative transfer.…”

Section: Satellite Datamentioning

confidence: 99%

Unveiling aerosol–cloud interactions – Part 1: Cloud contamination in satellite products enhances the aerosol indirect forcing estimate

et al. 2017

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Abstract. Increased concentrations of aerosol can enhance the albedo of warm low-level cloud. Accurately quantifying this relationship from space is challenging due in part to contamination of aerosol statistics near clouds. Aerosol retrievals near clouds can be influenced by stray cloud particles in areas assumed to be cloud-free, particle swelling by humidification, shadows and enhanced scattering into the aerosol field from (3-D radiative transfer) clouds. To screen for this contamination we have developed a new cloudaerosol pairing algorithm (CAPA) to link cloud observations to the nearest aerosol retrieval within the satellite image. The distance between each aerosol retrieval and nearest cloud is also computed in CAPA.Results from two independent satellite imagers, the Advanced Along-Track Scanning Radiometer (AATSR) and Moderate Resolution Imaging Spectroradiometer (MODIS), show a marked reduction in the strength of the intrinsic aerosol indirect radiative forcing when selecting aerosol pairs that are located farther away from the clouds ( − 0.28 ± 0.26 W m −2 ) compared to those including pairs that are within 15 km of the nearest cloud (−0.49±0.18 W m −2 ). The larger aerosol optical depths in closer proximity to cloud artificially enhance the relationship between aerosol-loading, cloud albedo, and cloud fraction. These results suggest that previous satellite-based radiative forcing estimates represented in key climate reports may be exaggerated due to the inclusion of retrieval artefacts in the aerosol located near clouds.

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Section: Satellite Datamentioning

confidence: 99%

Unveiling aerosol–cloud interactions – Part 1: Cloud contamination in satellite products enhances the aerosol indirect forcing estimate

et al. 2017

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“…This model is based on the two-stream doubling-adding solution to the radiative transfer equation with the assumption of a plane-parallel atmosphere [27]. BUGSrad computes molecular absorption and scattering properties based on correlated-k formulation [26].…”

Section: Data Preparationmentioning

confidence: 99%

“…One broadband flux covers the SW at 0-4 µm, and the other one covers the LW above 4 µm. Based on the comparison experiment with observations of the Atmospheric Radiation Measurement program, the mean biases of SW and LW in clear-sky conditions are 1.2 and 2.2 W m −2 at the TOA, respectively [27].…”

Section: Data Preparationmentioning

confidence: 99%

Impacts of 3D Aerosol, Cloud, and Water Vapor Variations on the Recent Brightening during the South Asian Monsoon Season

et al. 2018

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South Asia is experiencing a levelling-off trend in solar radiation and even a transition from dimming to brightening. Any change in incident solar radiation, which is the only significant energy source of the global ecosystem, profoundly affects our habitats. Here, we use multiple observations of the A-Train constellation to evaluate the impacts of three-dimensional (3D) aerosol, cloud, and water vapor variations on the changes in surface solar radiation during the monsoon season (June-September) in South Asia from 2006 to 2015. Results show that surface shortwave radiation (SSR) has possibly increased by 16.2 W m −2 during this period. However, an increase in aerosol loading is inconsistent with the SSR variations. Instead, clouds are generally reduced and thinned by approximately 8.8% and 280 m, respectively, with a decrease in both cloud water path (by 34.7 g m −2 ) and particle number concentration under cloudy conditions. Consequently, the shortwave cloud radiative effect decreases by approximately 45.5 W m −2 at the surface. Moreover, precipitable water in clear-sky conditions decreases by 2.8 mm (mainly below 2 km), and related solar brightening increases by 2.5 W m −2 . Overall, the decreases in 3D water vapor and clouds distinctly result in increased absorption of SSR and subsequent surface brightening.

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“…Existem várias versões deste método e todas apresentam praticamente a mesma acurácia (King & Harshvardhan, 1986). O método de dois fluxos tem sido usado para várias finalidades, como exemplo, Fu et al (1997) para estimar a transferência radiativa no IR e Stephens et al (2001) para deduzir fluxos de banda larga.…”

Section: Introductionunclassified

“…No caso de uma atmosfera estratificada, a equação geral de propagação pode ser reduzida a um par de equações diferenciais ou "método de dois fluxos", cuja solução resulta em um par de irradiâncias, uma ascendente e outra descendente (Ceballos, 1988;Liou, 1992). Os modelos de circulação atmosférica costumam utilizar o esquema de dois fluxos e, genericamente, consideram uma atmosfera com estratificação plano-paralela e cada camada povoada por arúmido ou por uma nuvem estratiforme (Stephens, 1984;Stephens et al, 2001). …”

Section: Introductionunclassified

Estimativa da radiação solar global à superfície usando um modelo estocástico: caso sem nuvens

Souza¹,

Silva²,

Ceballos

2008

Rev. Bras. Geof.

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ABSTRACT.A radiative transfer model was implemented for a 16-layer stratified atmosphere. The scheme is of a stochastic structure, with a random walk of diffuse photons between transition states until arriving to absorption states within layers, sky or ground. The formalism is associated a first order Markov process. The model exhibits a simple but powerful structure, when compared with other models used for multiple-layered atmospheres. The structure of the model allows the calculation of the planetary reflectance, global radiance in the surface and the absorption in the atmosphere. Transition parameters for each layer are calculated using a delta-SS two-flux approximation. Comparisons with surface measurements and with SBDART code (Santa Barbara DISORT Atmospheric Radiative Transfer), show a good performance of the model when assessing global radiation at ground level for Rayleigh atmospheres as well as for high-loaded aerosol atmospheres during burning season. The precision of the model, in the atmosphere transmittance estimation, makes it important for researchers that act in the area of remote sensing. Main advantages of the model are: simple structure, good accuracy and easy adaptation to an atmosphere composed of an even number of layers.Keywords: Solar radiation, irradiance, radiative transfer, stochastic model. RESUMO.Neste trabalho implementa-se um modelo de transferência radiativa numa atmosfera estratificada em 16 camadas. O esquema tem estrutura estocástica com transições aleatórias de fótons difusos de estados transitórios até um estado de absorção numa camada da atmosfera, no céu ou no solo. O formalismo está associado a uma cadeia de Markov de primeira ordem. O modeloé uma estrutura simples, mas eficiente quando comparado com outros modelos usados para atmosfera de múltiplas camadas. A estrutura do modelo permite o cálculo da refletância planetária, radiação solar globalà superfície e a absorção na atmosfera. Os parâmetros de transição são avaliados mediante aproximação delta-SS de dois fluxos. Verifica-se um bom desempenho do modelo ao se comparar a radiação solar globalà superfície com dados medidosà superfície e com o código SBDART (Santa Barbara DISORT Atmospheric Radiative Transfer). A precisão do modelo, na estimativa da transmitância da atmosfera, o torna importante para pesquisadores que atuam naárea de sensoriamento remoto. As principais vantagens do modelo utilizado são: estrutura simples, boa precisão e fácil adaptação para uma atmosfera composta por um número par de camadas.Palavras-chave: irradiância, fluxo radiativo, processo estocástico.

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Parameterization of Atmospheric Radiative Transfer. Part I: Validity of Simple Models

Cited by 86 publications

References 27 publications

Unveiling aerosol–cloud interactions – Part 1: Cloud contamination in satellite products enhances the aerosol indirect forcing estimate

Unveiling aerosol–cloud interactions – Part 1: Cloud contamination in satellite products enhances the aerosol indirect forcing estimate

Impacts of 3D Aerosol, Cloud, and Water Vapor Variations on the Recent Brightening during the South Asian Monsoon Season

Estimativa da radiação solar global à superfície usando um modelo estocástico: caso sem nuvens

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