Optical Properties of the Atmosphere (Revised)

McClatchey, R. A.; Fenn, Robert W.; Volz, Frederic E.; Garing, J. S.

doi:10.21236/ad0726116

Cited by 850 publications

(609 citation statements)

References 16 publications

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“…In order to evaluate the various search algorithms on the temperature inversion problem, we used five, well-known, McClatchey temperature profiles [6], which represent conditions ranging from subarctic winter to tropical summer.…”

Section: Resultsmentioning

confidence: 99%

Comparing Search Algorithms for the Temperature Inversion Problem

Lunacek

Whitley

Gabriel

et al. 2004

Genetic and Evolutionary Computation – GECCO 2004

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Abstract. Several inverse problems exist in the atmospheric sciences that are computationally costly when using traditional gradient based methods. Unfortunately, many standard evolutionary algorithms do not perform well on these problems. This paper investigates why the temperature inversion problem is so difficult for heuristic search. We show that algorithms imposing smoothness constraints find more competitive solutions. Additionally, a new algorithm is presented that rapidly finds approximate solutions.

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Section: Resultsmentioning

confidence: 99%

Comparing Search Algorithms for the Temperature Inversion Problem

Lunacek

Whitley

Gabriel

et al. 2004

Genetic and Evolutionary Computation – GECCO 2004

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“…Neste trabalho, a distribuição vertical dos componentes atmosféricosé feita com base numa atmosfera tropical de McClatchey et al (1971), que possui um perfil de umidade determinado, concentração de dióxido de carbono de 360 ppm, pressãoà superfície igual a 1013 hPa e ozônio com concentração variável com a altura, de aproximadamente 3 ppm perto da superfície, aumentando consideravelmente na estratosfera (máximo de 18 ppm aos 36 ESTIMATIVA DA RADIAÇÃO SOLAR GLOBALÀ SUPERFÍCIE USANDO UM MODELO ESTOCÁSTICO: CASO SEM NUVENS 25 km) e caindo para 2,14 × 10 −6 ppm acima de 100 km e coluna total em torno de 300 DU. Os conjuntos de parâmetros espectralmente discretos referentes a aerossol, ozônio e vapor d'água, assim como os valores da irradiância solar no topo da atmosfera, foram representados por funções contínuas obtidas através de ajustes de curvas.…”

Section: Componentes Atmosféricos No Modelounclassified

“…Alguns modelos empíricos, com base em dados experimentais, estabelecem valores numéricos de coeficientes de absorção. Leckner (1978), a partir de dados de McClatchey et al (1971), propôs a seguinte expressão para transmitância da radiação solar no nível da superfície,…”

Section: Aerossolunclassified

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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“…2 at some microwave frequencies. Two different atmospheric models, tropical (a) and mid latitude winter (b), described in McClatchey et al (1972) are used in this calculation. These figures, (a) and (b), have almost the same trend in spite of a big difference in both temperature profiles and a weak dependence of weighting function on an altitude at around 21 and 23GHz.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

A Method to Retrieve Precipitable Water Content Using a Microwave Spectro-Radiometer

Takamura

1996

Journal of the Meteorological Society of Japan

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A new method, utilizing a 22.235 GHz-water vapor emission line, to retrieve precipitable water content (PWC) is proposed. To obtain PWC, the method includes estimating the portion of the water vapor contribution to the brightness temperature, integrated over the microwave ) range. It is appropriate to use the K-band range in order to retrieve PWC because the emission (or absorption) in this frequency range is weak and the line strength is little dependent on atmospheric temperature and pressure.By using several atmospheric models with typical cloud types, the following approximate relation to retrieve PWC is introduced:where a=0.2135+0.0021, b=-0.0420+0.0251, Tb.obs(f) is a brightness temperature observed at a frequency of f GHz, and f1 and f2 are lower and upper boundary frequencies for integration, which are 18 and 26GHz, respectively, and df=f2-f1.dTb is a correction factor for the term correcting cloud and water vapor continuum emission. It is best for dTb to be set at 0.2K empirically.By using actual radiosonde data along with clouds introduced depending on atmospheric conditions, an error is determined from the above approximate method for retrieval of PWC. The error for PWC is less than 5% under the average atmospheric condition (PWC>1g/cm2 and liquid water path (LWP)<0.1g/m2), and is about 6% for rather cool atmospheric conditions (PWC<1g/cm2 and LWP<0.01g/m2).

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Optical Properties of the Atmosphere (Revised)

Cited by 850 publications

References 16 publications

Comparing Search Algorithms for the Temperature Inversion Problem

Comparing Search Algorithms for the Temperature Inversion Problem

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

A Method to Retrieve Precipitable Water Content Using a Microwave Spectro-Radiometer

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