The 2020-2023 La Niña: Did Cross-timescale Interference Fuel this Multi-year Event?

<p>Beginning July 2020, the Ni&#241;o 3.4 index crossed below the threshold to La Ni&#241;a conditions and remained below a -0.4 sea surface temperature anomaly through the spring of 2023, impacting agriculture, livelihoods, and communities around the world. What caused this prolonged La Ni&#241;a event and why was it sustained? How did the interaction between the different modes of climate variability influence the event? The internal dynamics of ENSO, the Indian Ocean Dipole, and the Madden-Julian Oscillation are studied here through a non-linear approach utilizing compositing techniques and both linear and non-linear wave superposition to identify what caused and prolonged the 2020-2023 La Ni&#241;a event.</p>