Two approaches are used: applying regressions to experiments as they approach equilibrium, and equilibrium experiments forced separately by CO2 and patterned sea surface temperature perturbations alone. (link.springer.com)
After the removal from the data set of short periods of temperature perturbation that relate to near - equator volcanic eruption, we use derivatives to document the presence of a 5 - to 7 - month delayed close relationship between SOI and GTTA. (climatedepot.com)
One of the identifiers for those eddies was noticeable water temperature perturbations within these swirls (sometimes as great as 2 - 4C as I recall). (realclimate.org)