Revisiting the Decadal Variability of Solar Photovoltaic Resource Potential in the Monsoon Climate Zone of East Asia Using Innovative Trend Analysis

In this study, we applied an innovative trend analysis (ITA) technique to detect the annual and seasonal trends of solar photovoltaic resource potential (Rs) in East Asia during 1961–2010 based on the Global Energy Balance Archive (GEBA) data. The Mann-Kendall (M-K) trend test and linear regression method (LRM) were compared with the ITA technique. The results showed that the annual Rs in China presented a significant decreasing trend (D<–0.5 and P<0.01, where P is the P-value and D is the trend indicator of ITA) using these three techniques. The seasonal Rs generally showed a significant decreasing trend (D<–0.5) using the ITA technique in China, however, a slightly increasing trend was observed in Japan. The Rs values were further divided into four groups (“low”, “moderate”, “high” and “very high”) to detect the sub-trends using the ITA technique. The results indicated that the decreasing annual Rs in China was mainly due to reductions in the “high” and “very high” Rs values. The most probable causes of the trends in the variation in China were the decreasing sunshine duration and increasing anthropogenic aerosol loadings; while the trends in Japan were probably driven by the increasing sunshine and declining cloud optical thickness. Moreover, the similarities and differences between the M-K test and ITA technique results were compared and evaluated, and the ITA technique proved to be superior to the M-K test.