DOI: 10.5281/zenodo.17383301
title: Post-Processed Output for super El Niño-induced Climate Regime Shifts

description: Post-Processed Output for Super El Nino-induced climate Regime Shifts

These dataset include the *post-processed diagnostics and intermediate outputs** used in the study:

“Super El Niño events drive Climate Regime Shifts with Enhanced Risks under Global Warming”, accepted in Nature Communications (2025).

🔹 Archived Content

###Reanalysis Datasets

(1) obs_SAT.zip:

Contains the surface air temperature Regime Shift Index (RSI) derived from multiple reanalysis and observational datasets, including AMIP II, COBE2, ERA5, ERSST v5, HadISST, HURRELL, and Kaplan.Each dataset is processed using multiple cut-off lengths (L) and significance levels (p) to assess the robustness of detected regime shifts across products and parameter settings.

(2) obs_SST.zip:

Contains the surface air temperature Regime Shift Index (RSI) derived from multiple reanalysis and observational datasets, including HadCRUT4, ERA5, GHCN-CAMS, GISS, MLOST, and NCEP.Each dataset is processed using multiple cut-off lengths (L) and significance levels (p) to assess the robustness of detected regime shifts across products and parameter settings.

(3) obs_soil_moisture.zip:

Includes the surface soil-moisture RSI derived from diverse land reanalysis and satellite products: ERA5, ERA5-Land, ESACCI, GLDAS 2.1, GLEAM, MERRA-2, PDSI, and TERRA.All data are detrended, standardized into anomalies, and analyzed using multiple cut-off lengths (L) and significance levels (p) under the same STARS framework.

(4) obs_SIC.zip:

Contains the Arctic and Antarctic sea-ice RSI, computed from the Hadley Center and National Snow and Ice Data Center (NSIDC) Sea Ice Index.

###Climate model simulations

1. cesm2_lens_regime_shift.zip:

This dataset provides the Regime Shift Index (RSI) calculated from the 100-member Community Earth System Model version 2 Large Ensemble (CESM2-LE) simulations. All three variables (SAT, SST and surface soil moisture) are detrended, converted to anomalies, and processed using the Sequential t-test Analysis of Regime Shifts (STARS) algorithm.

The data allow quantitative assessment of how internal variability, anthropogenic forcing, and extreme ENSO events influence the frequency and spatial pattern of climate regime shifts.

📂 Directory Structure





hist/ – Historical period (1850–2014)Contains regime-shift analyses for three major variables:





sat/ – Surface air temperature (SAT) RSI




sst/ – Sea surface temperature (SST) RSI




soil/ – Surface soil moisture RSI






ssp/ – SSP3-7.0 future projection (2015–2100)Contains the same variables and file structure as hist/, showing projected changes in climate regime-shift probability and frequency under high-emission forcing.




nino/ – ENSO diagnosticsContains the Niño3 index time series computed from CESM2 large ensemble SST anomalies. These indices are used to identify Super El Niño, regular El Niño, and neutral years, supporting composite analyses of Super El Niño-induced regime-shift probabilities.



2. cmip6_regime_shift.zip:

This archive provides the Regime Shift Index (RSI) computed from a CMIP6 multi-model ensemble  for SAT and SST.

📂 Directory Structure





hist/ — Historical period (model historical runs)





sat/ – Surface air temperature (SAT) RSI




sst/ – Sea surface temperature (SST) RSI






ssp/ — Future projections (e.g., SSP5-8.5)





Mirrors hist/ with sat/ and sst/ directories, providing projected changes in climate regime shifts.






nino/ — ENSO diagnostics





Contains Niño3 index time series derived from CMIP6 SST anomalies, used to classify Super El Niño, regular El Niño, and neutral years for composite analyses





🔗 The multiple SST reanalysis datasets used in this study are available from: 

(1) HadISST v1.1, https://www.metoffice.gov.uk/hadobs/hadisst/data/download.html;

(2) ERSSTv5: https://downloads.psl.noaa.gov/Datasets/noaa.ersst.v5/; 

(3) COBE SST2: https://www.esrl.noaa.gov/psd/data/gridded/data.cobe2.html; 

(4) Kaplan SST v2: https://psl.noaa.gov/data/gridded/data.kaplan_sst.html; 

(5) ERA5: https://cds.climate.copernicus.eu/datasets/reanalysis-era5-single-levels-monthly-means?tab=download; 

(6) HURRELL: https://climatedataguide.ucar.edu/climate-data/merged-hadley-noaaoi-sea-surface-temperature-sea-ice-concentration-hurrell-et-al-2008; 

(7) AMIPII: https://pcmdi.llnl.gov/mips/amip/AMIP2EXPDSN/BCS_OBS/amip2_bcs.html#source_data.

🔗 The multiple SAT reanalysis datasets are available from: 

(1) NCEP: https://downloads.psl.noaa.gov/Datasets/ncep.reanalysis/Monthlies/surface_gauss/air2m.mon.mean.nc; 

(2) MLOST: https://www.ncdc.noaa.gov/cag/time-series/global; 

(3) GISTEMP: http://data.giss.nasa.gov/gistemp; 

(4) HadCRUT4: https://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/download.html; 

(5) GHCN_CAMS: https://psl.noaa.gov/thredds/catalog/Datasets/ghcncams/catalog.html?dataset=Datasets/ghcncams/air.mon.mean.nc; 

(6) ERA5: https://cds.climate.copernicus.eu/datasets/reanalysis-era5-single-levels-monthly-means?tab=download.

🔗 The surface soil moisture reanalysis datasets are available from:

(1) CPC: https://psl.noaa.gov/data/gridded/data.cpcsoil.html; 

(2) NCEP: https://downloads.psl.noaa.gov/Datasets/ncep.reanalysis/Monthlies/surface_gauss/soilw.mon.mean.nc;

(3) TerraClimate: https://www.climatologylab.org/terraclimate.html; 

(4) ERA5: https://cds.climate.copernicus.eu/datasets/reanalysis-era5-single-levels-monthly-means?tab=download; 

(5) ERA5_land: https://cds.climate.copernicus.eu/datasets/reanalysis-era5-land?tab=download; 

(6) ESACCI: https://data.ceda.ac.uk/neodc/esacci/soil_moisture/data; 

(7) GLDAS: https://hydro1.gesdisc.eosdis.nasa.gov/data/GLDAS/GLDAS_CLSM10_M.2.0/; 

(8) GLEAM: https://www.gleam.eu/#downloads; 

(9) MERRA2: https://goldsmr4.gesdisc.eosdis.nasa.gov/data/MERRA2_MONTHLY/M2TMNXLND.5.12.4/; 

(10) scPDSI: https://crudata.uea.ac.uk/cru/data/drought/.

🔗 The sea ice concentration and sea ice extent reanalysis datasets are available from:

(1) Hadley SIC: https://www.metoffice.gov.uk/hadobs/hadisst/; 

(2) NSIDC SIE: https://noaadata.apps.nsidc.org/NOAA/G02135/seaice_analysis.

The CESM2-LE datasets are available from https://www.cesm.ucar.edu/experiments.

The CMIP6 archives are freely available from https://esgf-node.llnl.gov/search/cmip6/.

🔖 Citation

Xue, A., et al. (2025). Super El Niño events drive climate Regime Shifts with Enhanced Risks under Global Warming. Zenodo DOI: https://doi.org/10.5281/zenodo.17383301