El Nino Southern Oscillation and Atlantic Multidecadal Oscillation Impact on Hurricanes North Atlantic Basin

TL;DR

This study analyzes how ENSO, AMO, and SST variations influence the strength, frequency, and landfall patterns of hurricanes in the North Atlantic Basin, highlighting their increasing impact and potential for improved seasonal forecasting.

Contribution

It provides a comprehensive analysis of the combined effects of ENSO, AMO, and SSTs on Atlantic hurricanes using data from 1950 to 2023, revealing new insights into their influence on TC behavior.

Findings

Increasing SSTs correlate with stronger TCs.

Warm AMO phases are linked to higher TC frequency.

El Nino reduces landfalling TCs, La Nina or neutral conditions increase them.

Abstract

Tropical cyclones (TCs), including hurricanes and typhoons, cause significant property damage and result in fatalities, making it crucial to understand the factors driving extreme TCs. The El Nino Southern Oscillation (ENSO) influences TC formation through tropospheric vorticity, wind shear, and atmospheric circulations. Apart from atmospheric changes, oceans influence activity through sea surface temperatures (SSTs) and deep ocean heat content. These Atlantic SSTs determine the Atlantic Multidecadal Oscillation (AMO), which indicates SST variability in the Atlantic. This research focuses on ENSO, AMO, and SSTs impact on the strength and frequency of TCs in the North Atlantic Basin. AMO and SST anomalies are increasing at an alarming rate, but it remains unclear how their dynamics will influence future TC behavior. I used observational cyclone track data from 1950 to 2023, the Oceanic Nino Index (ONI), and NOAAs Extended Reconstructed SST V5 (ERSST). I found that Increasing SSTs over the past decade indicate stronger TCs, while warm phase AMO periods correspond with higher TC frequency. Meanwhile, a greater frequency of landfalling TCs can be attributed to La Nina or ENSO-neutral, with El Nino decreasing the frequency of landfalling TCs. Such relationships suggest that as the seasonal predictability of ENSO and SSTs improve, seasonal TC forecasts may improve.