441 / 2024-09-17 02:15:58
Exploring the Mutual Memory of Tropical Cyclones and Upper Ocean Conditions
tropical cyclone,upper ocean,air-sea interaction
Session 6 - Tropical Cyclone-Ocean Interactions: From Weather to Climate Scales
Abstract Review Pending
Tropical cyclones (TCs) and upper ocean conditions interact in ways that leave lasting imprints on both systems. Our study investigates these mutual “memories,” revealing how mesoscale ocean temperature anomalies influence TC characteristics and how TCs, in turn, modify the ocean surface. On the one hand, we show through simulations that while a TC's maximum wind speed recovers quickly after crossing sea surface temperature (SST) anomalies, its size-related features, including the radius of gale force winds and integrated kinetic energy (IKE), can be significantly altered for several days. These changes are strongly tied to cumulative SST exposure and are proportional to storm precipitation. Accurate SST forecasts along the TC track are crucial for improving size and IKE predictions.
On the other hand, TCs can also create memories in the ocean. An analysis of cold wakes—ocean surface temperature anomalies created by TCs—infers changes in TC lifetime maximum intensity (LMI), size, and IKE from cold wake intensity and size for the period 1982–2019. We find a globally enhanced local cold wake amplitude three days after the LMI, with a rate of −0.12 ± 0.04 °C per decade, while the cold wake size shows no significant change. While the inferred annual mean global LMI has increased by 1.0 ± 0.7 m s−1 per decade, TC size and destructive potential, as measured by IKE, have not shown any significant long-term changes.
This dual analysis highlights the importance of accurate SST forecasts along TC tracks for improving predictions of TC destructive potential. It also provides new independent and indirect evidence of recent TC intensity increases, while TC size and IKE have remained stable.
On the other hand, TCs can also create memories in the ocean. An analysis of cold wakes—ocean surface temperature anomalies created by TCs—infers changes in TC lifetime maximum intensity (LMI), size, and IKE from cold wake intensity and size for the period 1982–2019. We find a globally enhanced local cold wake amplitude three days after the LMI, with a rate of −0.12 ± 0.04 °C per decade, while the cold wake size shows no significant change. While the inferred annual mean global LMI has increased by 1.0 ± 0.7 m s−1 per decade, TC size and destructive potential, as measured by IKE, have not shown any significant long-term changes.
This dual analysis highlights the importance of accurate SST forecasts along TC tracks for improving predictions of TC destructive potential. It also provides new independent and indirect evidence of recent TC intensity increases, while TC size and IKE have remained stable.