Estimation of atmospheric turbidity coefficient b over Zhengzhou, China during 1961e2013 using an improved hybrid model

AIWEN LIN; LING ZOU; LUNCHE WANG; WEI GONG; HONGJI ZHU; GERMÁN A. SALAZAR

RENEWABLE ENERGY

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2015 vol. 86 p. 1134 - 1144

0960-1481

Accurate measurement and determination of the atmospheric turbidity is of great importance for solar radiation modeling and climate change studies. Daily values of global, direct and diffuse solar irradiation and meteorological variables (air temperature, relative humidity, sunshine duration and wind speed) during 1960e2013 are used to investigate the monthly variations of Ångstrom turbidity coef ? ficient (b) at Zhengzhou, China. An improved method (IYHM-ZZ) is proposed by combining the format of the Yang hybrid model (YHM) with corrected spectral terms. The b value is obtained by adjusting the estimated direct radiation until it matches the measured values. Statistical indicators (RMSE, MBE and t-test) are used to evaluate the performance of YHM and IYHM-ZZ models, and the IYHM-ZZ model produces more accurate estimates than the YHM model. The results indicate that the b values are generally higher in winter and spring, lower in summer and autumn. An increasing trend of b is observed during 1960e2010 at Zhengzhou, and the annual mean b are 0.07, 0.09, 0.11, 0.12, 0.12 and 0.13 for 1960s, 1970s, 1980s, 1990s, 2000s and 2010-, respectively