posted on 2023-05-17, 09:43authored byManuel NunezManuel Nunez, Utrillas, MP, Martinez-Lozano, JA
The paper explores methods of partitioning the hourly average UV erythemal flux into its direct and diffuse components for Valencia, Spain. It is shown that the cloud modification factor, the ratio of measured to cloudless erythemal flux relates linearly to the fraction of the measured irradiance that is diffuse. This relationship was developed further into two simple models- a linear and nonlinear one. The models are characterized by an effective cloud cover to partition the global erythemal flux. The diffuse fraction increases linearly with cloud cover in the linear model, but exponentially in the nonlinear one. The models may be used to partition the direct and diffuse irradiance with RMS errors values ranging from 5.7 to 6.8 mWm-2 and 6.0-7.7 mWm-2 for direct and diffuse, respectively, with the nonlinear model performing best overall.
History
Publication title
Journal of Geophysical Research
Volume
117
Article number
D02204
Number
D02204
Pagination
1-12
ISSN
0148-0227
Department/School
School of Geography, Planning and Spatial Sciences