Summary of Commonly Used ENSO Indices

This paper introduces 12 commonly used El Niño-Southern Oscillation (ENSO) indices and compares their creation based on different datasets, regions, representing anomalies, functions, advantages, and limits. It summarizes two application cases for each of the three different ENSO indices: Niño 3.4, Ocean Niño Index (ONI), and the Multivariate ENSO index (MEI). The application examples for Niño 3.4 are ENSO prediction and drought pattern analysis; for ONI, they are responses of ice shelves and rainfalls to ENSO; and for MEI, they are building two modeling approaches for ENSO monitoring and hydrological events prediction. The summary of these ENSO indices demonstrates their importance in climate studies in providing simplified anomalies for building models and making scientists communicate with each other about their findings in ENSO-related climate variabilities in agriculture, fisheries, water resource management, disaster preparedness, etc.