Phys.org February 7, 2023
Understanding and prediction of tropical cyclone (TC) activity on the medium range remains challenging. Researchers in the UK found that the pre-existing westward-moving equatorial waves can inform the risk of TC occurrence and intensification, based on a dataset obtained by synchronising objectively identified TCs and equatorial waves in a climate reanalysis. Globally, westward-moving equatorial waves can be precursors to 60–70% of pre-tropical cyclogenesis events, and to >80% of the events with the strongest vorticity, related to the favourable environmental conditions within the pouch of equatorial waves. They also found that when storms are in-phase with westward-moving equatorial waves, the intensification rate of TCs was augmented, while in other phases of the waves, storm intensity grows more slowly, or even decays. Coherent wave packets associated with TCs are identifiable up to two weeks ahead. According to the researchers their findings show that westward-moving equatorial waves can be useful medium-range precursors to TC activity… read more. Open Access TECHNICAL ARTICLEÂ
Percentages of pre-tropical cyclogenesis (pre-TCG) events matched in-phase to equatorial waves. Credit: Nature Communications volume 14, Article number: 511 (2023)Â