Assessment of Six Different Methods for the Estimation of Surface Ultra-Violet Fluxes at One Location in Uruguay

Claire Thomas, Agustín Laguarda Cirigliano, William Wandji Nyamsi, Antti Arola, Uwe Pfeifroth, Jörg Trentmann, Thierry Ranchin, Lucien Wald
2019 Proceedings of the ISES Solar World Congress 2019   unpublished
This communication assesses six methods estimating Ultra-Violet A and B (UV-A and UV-B) fluxes from satellite imagery, numerical weather models or ground measurements. The UV estimates from each method are compared to coincident 15 minutes in-situ measurements collected at one location in Uruguay from September 2015 to January 2019. The first method "LAAM" (Locally-Adapted Antón Martínez) combines Global Horizontal Irradiance (G) measured on site with satellite-derived daily Ozone
more » ... Ozone concentration. The second method "Wald" uses an empirical model onto satellite-retrieved solar broadband irradiance at the surface (SSI) produced by HelioClim-3 version 5 (HC3v5) to derive UV fluxes. The third method named "CAMS-UV", is one of the outputs of ECMWF numerical weather model. The three remaining methods are respectively named "Weighted_Kato HC3v5", "Discretized _Kato HC3v5" and "DWD SARAH-3". They rely on more sophisticated modelling of the atmosphere in cloud-free conditions using radiative transfer modelling combined to a cloud modification factor (or cloud extinction) derived from HC3v5. Outside an underestimation observed for the UV-B range for both CAMS-UV (-20 %) and for the empirical model (-29 %), methods demonstrated their ability to collect the temporal variability of the signal of the instrument on-ground; biases ranges from -2 to 4 % for UV-A and from 0 to 10 % for UV-B, RMSE are close to 15 % and almost all correlation coefficients exceed 0.96. This analysis gives precious elements for discussion about the performance of models mainly developed and validated over Europe and Africa.
doi:10.18086/swc.2019.42.12 fatcat:arodfvbvwngelapbz3vdvf2jta