Model Democracy in El Nio Southern Oscillation in a Changing Climate: The impact of internal variability on the observed change in the La Nia

In El Nio Southern Oscillation in a Changing Climate, An, T., Tziperman, E., and Li, T. are authors. The object is called theAm.geophys. Un., 2020).

Even if data quality wasn’t an issue, detecting observed change could depend on the time period in which the La Nia is diagnosed. When comparing 1945– 1979 with 1980– 2014. there is no change in the frequencies of La Nia events. 1a), although there is still a strengthened west-minus-east SST gradient in the equatorial Pacific (Supplementary Fig. 13b). Therefore, the observed multi-year La Niña change is subject to uncertainty and may be influenced by natural variability.

As in previous studies37,50,51, we use one experiment only from each model (the ‘model democracy’ approach) to avoid dominance by models with which many experiments are carried out such that each model is represented equally in the assessment of inter-model consensus and the ensemble mean change. Changes in ENSO might be subject to internal variability. The lower the noise level of natural variability is caused by the longer time window used to diagnose ENSO variability change. The influence from internal variability could be eliminated if two 100 year periods were used. The results of a multi century preindustrial control simulation show that the influence of internal variability in the ENSO cycle is increased in the twenty first century. We use all available models under different emission scenarios to test the sensitivity of our results.

The 10-m zonal wind and the total windspeed are what the LH means in this case. The intensity of WE Sp depends on the state. SST is related to a higher WES feedback because of a stronger mean zonal wind and a warmer background.