UV index and UV dose: aerosol correction
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Correction for the presence of aerosolsThere is no explicit correction for the variable presence of aerosols in the TEMIS UV data products: they are are produced with an empirical algorithm assuming fixed aerosol conditions. The implicit UV aerosol optical depth (AOD), at 368 nm is about 0.30 with a single scattering albedo of about 0.9 [Badosa and Van Weele, 2002; Allaart et al., 2004].
An Angstrom coefficient can be used to convert the AOD at 368 nm to the AOD at 550 nm. Excluding situations dominated by coarse particles, such as wind blown dust and sea spray, the aerosol optical extinction would be dominated by fine mode particles. For an Angstrom coefficient of 1.5 [Frieß et al., 2016] the implicit aerosol conditions in the TEMIS UV data products correspond to an AOD of about 0.16 at 550 nm.
The aerosol standard conditions are assumed to be representative for areas where people live. In situations with bad air quality the TEMIS UV data products might overestimate the UV exposure, while in very clean background conditions a (slight) underestimation of the UV exposure might be expected.
- Allaart, M., Van Weele, M., Fortuin P. and Kelder, H.: 2004,
- An Empirical model to predict the UV-index based on solar zenith angle and total ozone
- Meteorological Applications (Royal Met. Society), 11, 59-65.
- Badosa, J. and Van Weele, M.: 2002,
- Effects of aerosols on UV-index
- KNMI Scientific Report WR-2002-07.
- [ PDF file ]
- Frieß, U., Klein Baltink, H., Beirle, S., Clémer, K., Hendrick, F., Henzing, B., Irie, H., de Leeuw, G., Li, A., Moerman, M. M., van Roozendael, M., Shaiganfar, R., Wagner, T., Wang, Y., Xie, P., Yilmaz, S., and Zieger, P.: 2016,
- Intercomparison of aerosol extinction profiles retrieved from MAX-DOAS measurements
- Atmos. Meas. Tech. 9, 3205-3222.
19 February 2019
data product contact: Jos van Geffen & Michiel van Weele & Ronald van der A
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