Ultraviolet Radiation over Two Lakes in the Middle and Lower Reaches of the Yangtze River, China: An Innovative Model for UV Estimation

Abstract

This study aims to explore the characteristics of ultraviolet (UV) radiation over Dong Lake (DL) and Tai Lake (TL) in the middle and lower reaches of the Yangtze River and to develop an innovative model for UV estimation under all weather conditions. The characteristic analysis of UV radiation shows distinctly hourly and monthly variations at two typical sites. The maximum values can represent the hourly UV feature, and the median and the arithmetic mean values are reasonably similar with little difference for both stations. The monthly means of hourly UV radiation range from 25.68 to 70.07 kJ m -2 for DL and between 36.00 and 92.62 kJ m -2 for TL. The monthly mean hourly UV fractions vary from 3.79% to 4.93% at DL and between 4.57% and 5.94% at TL. Comparisons on the monthly mean hourly values of UV radiation and UV fraction, the values at TL are always greater than those at DL. An innovative model is constructed based on two input parameters, namely the effect of the comprehensive attenuation factors for assumed cloud-free conditions (CAF UVclear ) and the effect of the clouds (K g ). CAF UVclear is derived from empirical models based on relative optical air mass and ozone. The effectiveness of the presented model is demonstrated by comparing with other two estimation models. This innovative model presents values of RMSE better than two reported models either at local place or a different locality. It indicates that this new model can provide satisfactory estimates of UV radiation at different localities other than the local place of origin where the relationships are developed.

Relations between erythemal UV dose, global solar radiation, total ozone column and aerosol optical depth at Uccle, Belgium

“…Surface albedo is determined mostly by snow amount and snow depth (Rieder et al, 2010) and plays a significant role at high-altitude and highlatitude sites, where UV irradiance can be strongly enhanced due to multiple occurrences of scattering and reflection between snow-covered ground and the atmosphere (Fitzka et al, 2012). Several studies have been conducted to quantify the effects of the abovementioned variables on the amount of UV irradiance reaching the ground, and many of them have done so by constructing empirical models with UV irradiance (or a related quantity) as a dependent variable (Díaz et al, 2000;Fioletov et al, 2001;de La Casinière et al, 2002;Foyo-Moreno et al, 2007;Antón et al, 2009;De Backer, 2009;Huang et al, 2011;Krishna Prasad et al, 2011;El Shazly et al, 2012).…”

Diurnal and Annual Evolution of UV, PAR and NIR Irradiations in Botucatu/Brazil

“…The estimation error of PAR radiation is associated with inaccuracy in measurement of I G and I NIR irradiance by the Eppley pyranometer, and I UV irradiance by the UV Kipp &Zonen radiometer. Uncertainty values of 4.1% and 5.0% are found for the PSP pyranometer [16] and UV Kipp & Zonen radiometer [17], respectively. Therefore, total uncertainty of PAR estimate is 7.7% [16].…”

Estimation of Daily Ultraviolet Radiation in Beijing Using a Semiempirical Method

“…established five empirical models for any atmospheric condition and any zenith angle between the main influence factors on UV radiation; Huang et al . developed an innovative model for UV estimation under all weather conditions by assuming cloudless conditions and considering the clearness index; and Hu et al . developed an experiential estimation model based on the relationship of the global broadband hemispherical transmittance and optical air mass for all sky conditions.…”

“…The former is mainly based on establishing an empirical expression between UV radiation and total radiation, ozone, clearness index or other parameters. For example, Mateos et al (22) established five empirical models for any atmospheric condition and any zenith angle between the main influence factors on UV radiation; Huang et al (9) developed an innovative model for UV estimation under all weather conditions by assuming cloudless conditions and considering the clearness index; and Hu et al (23) developed an experiential estimation model based on the relationship of the global broadband hemispherical transmittance and optical air mass for all sky conditions. The latter estimated the surface UV radiation using the radiative transfer model, which can model the process of atmospheric absorption and scatter and only requires various conventional atmospheric factors as inputs.…”