On the midlatitude thermal response to tropical warmth

[1] Observations reveal a global-scale thermal response to El Nino and La Nina, featuring a band of tropospheric anomalies opposite in sign to those in the tropics. When an idealized dynamical model is forced by increased tropical heating, a similar response, with an enhanced subtropical thermal gradient, results. In the idealized model, this response is produced by changes in transient eddy fluxes of heat and momentum, and consequent changes in the mean meridional circulation. The similarity between the two-level model results and those from observations, as well as the zonally averaged behavior of a GCM, suggests that the same dynamics operate in nature. This represents a tropical-midlatitude teleconnection distinct from and in addition to that mediated by stationary Rossby wave trains.