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Sensitivity of erythemal UV/global irradiance ratios to atmospheric parameters: application for estimating erythemal radiation at four sites in Thailand

journal contribution
posted on 2023-05-18, 07:26 authored by Buntoung, S, Janjai, S, Manuel NunezManuel Nunez, Choosri, P, Pratummasoot, N, Chiwpreecha, K
Factors affecting the ratio of erythemal UV (UVER) to broadband (G) irradiance were investigated in this study. Data from four solar monitoring sites in Thailand, namely Chiang Mai, Ubon Ratchathani, Nakhon Pathom and Songkhla were used to investigate the UVER/G ratio in response to geometric and atmospheric parameters. These comprised solar zenith angle, aerosol load, total ozone column, precipitable water and clearness index. A modeling scheme was developed to isolate and examine the effect of each individual environmental parameter on the ratio. Results showed that all parameters with the exception of solar zenith angle and clearness index influenced the ratios in a linear manner. These results were also used to develop a semi-empirical model for estimating hourly erythemal UV irradiance. Data from 2009 to 2010 were used to construct the ratio model while validation was performed using erythemal UV irradiance at the above four sites in 2011. The validation results showed reasonable agreement with a root mean square difference of 13.5% and mean bias difference of − 0.5%, under all sky conditions and 10.9% and − 0.3%, respectively, under cloudless conditions.


Publication title

Atmospheric Research








School of Geography, Planning and Spatial Sciences


Elsevier Science Inc

Place of publication

360 Park Ave South, New York, USA, Ny, 10010-1710

Rights statement

Copyright 2014 Elsevier B.V.

Repository Status

  • Restricted

Socio-economic Objectives

Air quality, atmosphere and weather not elsewhere classified

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