Aerosol optical properties and their effect on the UV solar irradiance at Uccle, Belgium

Abstract. Direct observation of the Sun at large solar zenith angles during the second SAGE III Ozone Loss and Validation Experiment (SOLVE II)/Validation of International Satellites and study of Ozone Loss (VINTERSOL) campaign by several instruments provided a rich dataset for the retrieval and analysis of line-of-sight column composition, intercomparison, and measurement validation. A flexible, multi-species spectral fitting technique is presented and applied to spectral solar irradiance measurements made by the NCAR Direct beam Irradiance Atmospheric Spectrometer (DIAS) on-board the NASA DC-8. The approach allows for the independent retrieval of O3, O2·O2, and aerosol optical properties, by constraining Rayleigh extinction. We examine the 19 January 2003 and 6 February 2003 flights and find very good agreement of O3 and O2·O2 retrievals with forward-modeling calculations, even at large solar zenith angles, where refraction is important. Intercomparisons of retrieved ozone and aerosol optical thickness with results from the Ames Airborne Tracking Sunphotometer (AATS-14) are summarized.

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Column ozone and aerosol optical properties retrieved from direct solar irradiance measurements during SOLVE II

Atmospheric Chemistry and Physics ◽

10.5194/acp-5-611-2005 ◽

2005 ◽

Vol 5 (3) ◽

pp. 611-622 ◽

Cited By ~ 3

Author(s):

W. H. Swartz ◽

J.-H. Yee ◽

R. E. Shetter ◽

S. R. Hall ◽

B. L. Lefer ◽

...

Keyword(s):

Optical Properties ◽

Solar Irradiance ◽

Aerosol Optical Properties ◽

Ozone Loss ◽

Spectral Fitting ◽

Validation Experiment ◽

Measurement Validation ◽

Column Ozone ◽

Spectral Solar Irradiance ◽

Good Agreement

Abstract. Direct observation of the Sun at large solar zenith angles during the second SAGE III Ozone Loss and Validation Experiment (SOLVE II)/Validation of International Satellites and study of Ozone Loss (VINTERSOL) campaign by several instruments provided a rich dataset for the retrieval and analysis of line-of-sight column composition, intercomparison, and measurement validation. A flexible, multi-species spectral fitting technique is presented and applied to spectral solar irradiance measurements made by the NCAR Direct beam Irradiance Atmospheric Spectrometer (DIAS) on-board the NASA DC-8. The approach allows for the independent retrieval of O3, O2·O2, and aerosol optical properties, by constraining Rayleigh extinction. We examine the 19 January 2003 and 6 February 2003 flights and find very good agreement of O3 and O2·O2 retrievals with forward-modeling calculations, even at large solar zenith angles, where refraction is important. Intercomparisons of retrieved ozone and aerosol optical thickness with results from the Ames Airborne Tracking Sunphotometer (AATS-14) are summarized.

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All-Sky Imager: A New Instrument for the Estimation of Solar Irradiance, Cloudiness and Aerosol Optical Properties

Perspectives on Atmospheric Sciences - Springer Atmospheric Sciences ◽

10.1007/978-3-319-35095-0_169 ◽

2016 ◽

pp. 1175-1180

Author(s):

A. Kazantzidis ◽

P. Tzoumanikas ◽

E. Nikitidou ◽

V. Salamalikis

Keyword(s):

Optical Properties ◽

Solar Irradiance ◽

Aerosol Optical Properties ◽

New Instrument ◽

Sky Imager

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Development of on-site self-calibration and retrieval methods for sky-radiometer observations of precipitable water vapor

10.5194/amt-2019-426 ◽

2019 ◽

Author(s):

Masahiro Momoi ◽

Rei Kudo ◽

Kazuma Aoki ◽

Tatsuhiro Mori ◽

Kazuhiko Miura ◽

...

Keyword(s):

Optical Properties ◽

Water Vapor ◽

Solar Irradiance ◽

Precipitable Water ◽

Dry Season ◽

Calibration Constant ◽

Aerosol Optical Properties ◽

Vapor Channel ◽

Long Term Observation

Abstract. The Prede sky-radiometer, whose aerosol channels are calibrated by on-site measurements (the Improved Langley method), has been used for continuous long-term observation of aerosol properties. However, continuous long-term observation of precipitable water vapor (PWV) by sky-radiometer remain challenge, because the water vapor channel is generally calibrated by the standard Langley method at limited observation sites (e.g., the Mauna Loa Observatory). In this study, we developed SKYMAP, a new onsite self-calibration method for the water vapor channel of the Prede sky-radiometer using diffuse radiances normalized by direct solar irradiance. The SKYMAP algorithm consists of three steps. First, aerosol optical and microphysical properties are retrieved using direct solar irradiances and the normalized diffuse radiances at aerosol channels. The aerosol optical properties at the water vapor channel are interpolated from those at aerosol channels. Second, the transmittance of PWV is retrieved using the diffuse radiance normalized to the direct solar irradiance at the water vapor channel, which does not need the calibration constant. Third, the calibration constant at the water vapor channel is estimated from the transmittance of PWV and aerosol optical properties. Intensive sensitivity tests of SKYMAP using simulated data of the sky-radiometer showed that the calibration constant is retrieved reasonably well for PWV < 2 cm, indicating that SKYMAP can calibrate the water vapor channel on-site in dry conditions. Then SKYMAP was applied to actual measurements in the dry season at two sites (Tsukuba and Chiba, Japan). Because the SKYMAP algorithm is useful for clear-sky and low PWV (< 2 cm) conditions, the water vapor channel was calibrated for the dry season. After determining the calibration constant, PWV is able to be retrieved using direct solar irradiances for the whole year. The retrieved PWV values correspond well to those derived from a Global Navigation Satellite System (GNSS)/Global Positioning System (GPS) receiver, a microwave radiometer, and a AERONET sun-sky radiometer at both sites (correlation coefficient γ > 0.96), indicating that the Prede sky-radiometer provides both aerosol and PWV data based on its unique on-site calibration methods.

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Renewal of aerosol data for ALADIN-HIRLAM radiation parametrizations

Advances in Science and Research ◽

10.5194/asr-16-129-2019 ◽

2019 ◽

Vol 16 ◽

pp. 129-136 ◽

Cited By ~ 2

Author(s):

Laura Rontu ◽

Joni-Pekka Pietikäinen ◽

Daniel Martin Perez

Keyword(s):

Optical Properties ◽

Solar Irradiance ◽

Climate Models ◽

Climate Model ◽

Weather Prediction ◽

Aerosol Optical Properties ◽

Maximum Reduction ◽

Screen Level ◽

The Impact

Abstract. Radiative transfer calculations in numerical weather prediction (NWP) and climate models require reliable information about aerosol concentration in the atmosphere, combined with data on aerosol optical properties. Replacement of the default input data on vertically integrated climatological aerosol optical depth at 550 nm (AOD550, Tegen climatology) with newer data, based on those available from Copernicus atmosphere monitoring service (CAMS), led to minor differences in the simulated solar irradiance and screen-level temperature in the regional climate model HCLIM-ALARO simulations over Scandinavia and in a clear-sky case study using HARMONIE-AROME NWP model over the Iberian peninsula. In the case study, replacement of the climatological AOD550 with that based on three-dimensional near-real-time aerosol mass mixing ratio resulted in a maximum reduction of the order of 150 W m−2 in the simulated local solar irradiance at noon. Corresponding maximum reduction of the screen-level temperature by almost two degrees was found. The large differences were due to a dust intrusion from Sahara, which is obviously not represented in the average climatological distribution of dust aerosol. Further studies are needed in order to introdude updated aerosol optical properties of all available aerosol types at different wavelengths, make them available for the radiation schemes of ALADIN-HIRLAM and test the impact on the predicted radiation fluxes.

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