Meaning of Successive Iteration of the Auxiliary Equation in the Theory of Radiative Transfer.

Dave, J. V.

doi:10.1086/148024

Cited by 111 publications

(76 citation statements)

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“…If /measured < /ground, the backscattered radiation is thought to be entirely from the surface and is determined by solving the boundary condition of the radiative transfer equation [Dave, 1964]. Equation ( Table 3.…”

Section: Toms Erythemal Uvr Exposure Algorithmmentioning

confidence: 99%

Surface UV radiation over Australia, 1979–1992: Effects of ozone and cloud cover changes on variations of UV radiation

Udelhofen¹,

Gies²,

Roy³

et al. 1999

J. Geophys. Res.

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Section: Toms Erythemal Uvr Exposure Algorithmmentioning

confidence: 99%

Surface UV radiation over Australia, 1979–1992: Effects of ozone and cloud cover changes on variations of UV radiation

Udelhofen¹,

Gies²,

Roy³

et al. 1999

J. Geophys. Res.

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“…The global coverage afforded by satellite observations of UV irradiance, or flux density (energy per unit area per unit time), can be used to distinguish regional and global changes in contrast to purely local observations from ground-based instru-TOMS backscattered radiance data using tables generated from the plane-parallel multiple-scattering radiative transfer program [Dave, 1964;Dave and Gazdag, 1970]. The tables include the effects of terrain height, solar zenith angle, ozone absorption, Rayleigh scattering, aerosol scattering and absorption, 340-380 nm surface reflectivity, and a pseudospherical geometry correction (spherical geometry for the unattenuated solar beam and for first-order scattering, with plane-parallel geometry for higher-order scattering).…”

Section: Introductionmentioning

confidence: 99%

Distribution of UV radiation at the Earth's surface from TOMS‐measured UV‐backscattered radiances

Herman¹,

Krotkov²,

Celarier³

et al. 1999

J. Geophys. Res.

228

241

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Abstract. Daily global maps of monthly integrated UV-erythemal irradiance (290-400 nm) at the Earth's surface are estimated using the ozone amount, cloud transmittance, aerosol amounts, and surface reflectivity from the solar UV radiation backscattered from the Earth's atmosphere as measured by the total ozone mapping spectrometer (TOMS) and independently measured values of the extraterrestrial solar irradiance. The daily irradiance values at a given location show that short-term variability (daily to annual) in the amount of UV radiation, 290-400 nm, reaching the Earth's surface is caused by (1) partially reflecting cloud cover, (2) haze and absorbing aerosols (dust and smoke), and (3) ozone. The reductions of UV irradiance estimated from TOMS data can exceed 50 +_ 12% underneath the absorbing aerosol plumes in Africa and South America (desert dust and smoke from biomass burning) and exceeded 70 _ 12% during the Indonesian fires in September 1997 and again during March 1998. Recent biomass burning in Mexico and Guatemala have caused large smoke plumes extending into Canada with UV reductions of 50% in Mexico and 20% in Florida, Louisiana, and Texas. Where available, ground-based Sun photometer data show similar UV irradiance reductions caused by absorbing aerosol plumes of dust and smoke. Even though terrain height is a major factor in increasing the amount of UV exposure compared to sea level, the presence of prolonged clear-sky conditions can lead to UV exposures at sea level rivaling those at cloudier higher altitudes. In the equatorial regions, +_20 ø, the UV exposures during the March equinox are larger than during the September equinox because of increased cloudiness during September. Extended land areas with the largest erythemal exposure are in Australia and South Africa where there is a larger proportion of clear-sky days. The large short-term variations in ozone amount which occur at high latitudes in the range _+65 ø cause changes in UV irradiance comparable to clouds and aerosols for wavelengths between 280 nm and 300 nm that are strongly absorbed by ozone. The absolute accuracy of the TOMS monthly erythemal exposure estimates over a TOMS field of view is within +_6%, except under UV-absorbing aerosol plumes (dust and smoke) where the accuracy is within +_ 12%. The error caused by aerosols can be reduced if the height of the aerosol plume is more accurately known. The TOMS estimated irradiances are compared with ground-based Brewer spectroradiometer data obtained at Toronto, Canada. The Brewer irradiances are systematically 20% smaller than TOMS irradiance estimates during the summer months. An accounting of systematic errors brings the Brewer and TOMS irradiances into approximate agreement within the estimated instrumental uncertainties for both instruments. IntroductionThe global coverage afforded by satellite observations of UV irradiance, or flux density (energy per unit area per unit time), can be used to distinguish regional and global changes in contrast to purely local observations from grou...

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“…0148-0227/97/96JD-03965509.00 amounts are used in a radiative transfer calculation [Dave, 1964] in order to compute radiances with which the measured radiances are compared in the ozone computation [McPeters et al, 1993]. A set of five fixed temperature profiles are used, including one each for low, middle, and high latitudes and a separate temperature profile for each of the 125 and 175 Dobson unit (DU) ozone profiles which characterize ozone hole conditions.…”

Section: Paper Number 96jd03965mentioning

confidence: 99%

A correction for total ozone mapping spectrometer profile shape errors at high latitude

Wellemeyer¹,

Taylor²,

Seftor³

et al. 1997

J. Geophys. Res.

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Abstract. The total ozone mapping spectrometer (TOMS) ozone measurement is derived by comparing measured backscatter ultraviolet radiances with theoretical radiances computed using standard climatological ozone profiles. Profile shape errors occur in this algorithm at high optical path lengths whenever the actual vertical ozone distribution differs significantly from the standard profile used. These errors are estimated using radiative transfer calculations and measurements of the actual ozone profile. These estimated errors include a shortterm component resulting from day-to-day variability in profile shape that gives rise to a standard deviation of 10% in total column ozone amount, as well as a systematic error in the long-term trend at very high solar zenith angles. The trend error resulting from the long-term changes in the ozone profile shape is estimated using measurements from the solar backscattered ultraviolet instrument. At the maximum retrieval solar zenith angle of 88 ø , these calculations indicate that TOMS long-term ozone depletions may be overestimated by 5% per decade.

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Meaning of Successive Iteration of the Auxiliary Equation in the Theory of Radiative Transfer.

Cited by 111 publications

References 0 publications

Surface UV radiation over Australia, 1979–1992: Effects of ozone and cloud cover changes on variations of UV radiation

Surface UV radiation over Australia, 1979–1992: Effects of ozone and cloud cover changes on variations of UV radiation

Distribution of UV radiation at the Earth's surface from TOMS‐measured UV‐backscattered radiances

A correction for total ozone mapping spectrometer profile shape errors at high latitude

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