NASA-SSH ENSO Sea Surface Height Indicator

This file contains an indicator for the El Nino-Southern Oscillation (ENSO), based on satellite observations of sea surface height anomaly, measured by radar altimeter missions such as TOPEX/Poseidon, the Jason series, and Sentinel-6. The indicator values were calculated using NASA-SSH Simple Gridded Sea Surface Height from Standardized Reference Missions Only Version 1 podaac.jpl.nasa.gov/dataset/NASA_SSH_REF_SIMPLE_GRID_V1 .

Indicator values were calculated using cyclostationary empirical orthogonal functions (CSEOFs; Kim et al., 2015) computed by decomposing the gridded sea surface height anomalies over the time period from 1993 to 2019. After removing the linear trend from each individual gridded location, three sets of regional CSEOFs were generated, one each for ENSO, the Pacific Decadal Oscillation (PDO) and Indian Ocean Diode (IOD). In each case, the dominant statistical mode represents the seasonal cycle.