Abstract:
ERA5 reanalysis data and swell-index are used to study the swell pools in the low latitude areas of the Pacific, Atlantic and Indian Oceans, and analyze the causes of the Pacific swell pools. The results show that the southeast part of the Pacific swell pools is caused by the northward propagation of waves from the South Pacific, while the northwest part is caused by the southward propagation of waves from the North Pacific. The middle part of the swell pools is affected by both. The area of the Pacific swell pools is larger in winter (DJF) and smaller in summer (JJA). The swells in the winter hemisphere can spread farther and even cross the equator, thus the swells staying in low latitude sea area of the winter hemisphere are less. At the same time, the wind waves in the winter hemisphere is strongest all year around, resulting in the reduction in the swell pools area in the winter hemisphere. The propagation distance of the swells in the summer hemisphere is short, so the swells will "accumulate" in the low latitude sea area of the hemisphere. At the same time, the wind waves in the summer hemisphere is the weakest all year around, leading to the increase in the swell pools area in the summer hemisphere. The strength of wind field in the sea area where the swell pools is located is weak and the wind waves is feeble, creating favorable conditions for dominance of swells. When El Niño or La Niña occurs, it will strengthen or weaken the swells propagated to the low latitude Pacific region, thus affecting the spatial distribution of swell pools. The analysis of the temporal and spatial variation of swell pools is of great significance to the study of large-scale propagation of swells.