The climatic mutation in the long-term trends of wind and wave energies in the south China sea

A precise understanding of long-term trends in wind and wave energy and their underlying mechanisms is essential for the planning and sustainable development of marine renewable energy resources. Based on 45 years (1980–2024) of continuous model reanalysis data, this study systematically investigates the long-term trend, climate mutation, and their associations with large-scale climate variability for wind and wave energies in the South China Sea (SCS). The results reveal significant seasonal and spatial heterogeneity in wind and wave energy trends, with two notable climate mutations identified around 1995 and 2005. Around 1995, the springtime trend of wave energy shifted from increasing to decreasing. Besides, the growth trend in the northern SCS and the decline trend in the southern SCS both slowed down for the summertime wind energy. A further intensification in the wintertime trends of both wind and wave energy occurred around 2005. These trend mutations are strongly linked to broader climate variability, particularly through changes in the amplitude of the Niño 3.4 index, which affected the frequency of strong wind events, and the phase transitions in the Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation, which modulated the intensity of the SCS monsoon system and regional wind fields over the western Pacific. By detecting and quantifying the spatiotemporal variability of the energies' trend mutations and establishing robust connections with climate indices, this study provides critical insights for regional energy resource planning, climate risk assessment, and the development of adaptive policy strategies.