Analysis and evaluation of solar energy resource change characteristics in the Wanshan Island area

The total solar radiation and insolation hours in Wanshan Island were analyzed by linear regression analysis, distance level analysis method, 5-year sliding average method, and Mann-Kendall test method. The results showed that the total solar radiation in Wanshan Island showed a slight upward trend, and the total monthly solar radiation showed a unimodal distribution, with the highest in July and the lowest in February. The number of annual sunshine hours showed a weak downward trend, and the number of monthly sunshine hours showed a double-peak distribution, with the highest in July and the lowest in March. The analysis and evaluation of solar energy resources in the Wanshan Island area show that the annual average of total solar radiation in the Wanshan Island area is 4,996.25 MJ/m2, belonging to a resource-rich area. The indicator of the stability of solar energy resources is 3.7, which belongs to the resources of more stable areas.