First Effort for Constructing a Direct Solar Radiation Data Set in China for Solar Energy Applications

Abstract

Accurate estimate of direct solar radiation is a prerequisite for the design of concentrated solar power thermal systems; however, direct radiation observations are very sparse compared to observations of routine meteorological variables. Therefore, this study developed a method for estimating daily direct radiation from routine observations, based mainly on a clear‐sky physical model to compute clear‐sky direct radiation and a parameterized formula to compute cloud transmittance from sunshine duration data. The parameters of the cloud transmittance formula were calibrated with high‐quality radiation data measured in the United States. The validation results at independent stations in the United States were comparable to those at the calibration stations, indicating that the method is suitable for various climatic and geographic conditions. We applied this method to compile a long‐term, high‐density data set of daily direct radiation over China based on observations from 2,473 routine weather stations of the China Meteorological Administration (CMA) network. Although the root‐mean‐square error of the data set from the 20 CMA radiation stations at which the direct solar radiations have been observed since 1993 is about 27.3 W m−2, the accuracy of the data set for CMA routine weather stations with less severe air pollution should be better. The newly developed data set in this study, which is available upon request, will contribute to the development of concentrated solar power thermal systems throughout China.

Variability in Direct and Diffuse Solar Radiation Across China From 1958 to 2017

“…Other statistical indicators include the following: the correlation coefficient (r), mean bias error (bias), root-mean-square error, and relative root-mean-square error. (Li et al, 2011;Tang et al, 2018). The observed trends in R s and R dir appear to be steeper (likely spurious) than the derived trends during the period 1970-1989 (Figures 1c1 and 1d1).…”

“…The equations of R dir and R dif are regressed based on the observed direct and diffuse solar radiation from 16 CMA stations during the period 1994–2014. Analogously, the calculation formula for the monthly derived R dir data set is improved based on that for the derived R s data set (He et al, ; Tang et al, ; Yang et al, ), as shown in equation : …”

A 16-year dataset (2000–2015) of high-resolution (3 h, 10 km) global surface solar radiation

“…Firstly, the estimated SSR were validated against the observations measured at the 42 BSRN stations at both instantaneous and daily scales. To reduce the uncertainties induced by broken clouds, we validated the estimated instantaneous SSR against hourly mean observed ones centered on the time of satellite overpass, according to the suggestion of Wang and Pinker (2009). To examine the effect of different spatial resolutions on the accuracy of our SSR estimates, in addition to the 10 km spatial resolution, we also evaluated our estimated SSR at spatial resolutions of 30, 50, 70, 90 and 110 km, derived by averaging the SSR values observed at the original scale of 10 km.…”

Daily Global Solar Radiation in China Estimated From High‐Density Meteorological Observations: A Random Forest Model Framework

“…Daily global solar radiation (DGSR), as the major energy source of the Earth, plays a key role in the terrestrial radiation balance, energy exchange, hydrological cycle, photosynthesis, and the formation of weather and climate (Cooter & Dhakhwa, 1996;Cline et al, 1998;Hoogenboom, 2000;Power, 2001;Pohlert, 2004;Wild, 2009). DGSR is also crucial for the utilization of solar energy through transformation of technologies (Wu et al, 2012(Wu et al, , 2016Tang et al, 2018;Prăvălie et al, 2019;Zou et al, 2019). In recent years, there has been an aggravation of air pollution in China induced by massive fossil fuel consumption and emissions coinciding with unfavorable weather conditions (Guo et al, 2016Lou et al, 2019;Yang, et al, 2018;Yang, Ye, et al, 2019;Zheng et al, 2019).…”

“…On the one hand, this has significantly modulated the change in surface solar radiation (Che et al, 2005;Guo et al, 2018;Wang et al, 2012Wang et al, , 2013Wang & Wild, 2016;Zheng et al, 2018;He & Wang, 2020;Yang et al, 2020), while on the other hand, it has led to solar radiation becoming one of the fastest-growing and important sources of clean and renewable energy. Therefore, solar radiation is a topic that has attracted broad and increasing attention in China (Che et al, 2005;Sun et al, 2016;Li et al, 2017;Song et al, 2019;Tang et al, 2016Tang et al, , 2018Liu et al, 2019;He & Wang et al, © 2020 The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.…”