Abstract
Abstract
Greenhouse warming features spatial variations in sea surface temperature (SST) that modulate circulation, precipitation, and radiation. While South Pacific SST pattern has recently been explained by Southern-Hemisphere feedbacks, North Pacific warming remains poorly understood. Here we decompose coupled SST pattern formation into the effects of atmospheric responses to a spatially uniform SST increase (SUSI) and the direct CO₂ effect, radiative feedbacks, and air-sea interactions. Our heat budget shows significant mid-latitude warming driven by a stability response due to warm-air advection, reinforced by the surface radiative effects of melting sea ice and rising atmospheric moisture. Moderately enhanced subtropical warming reflects anomalous latent heating in SUSI: weakened surface winds associated with reduced subtropical anticyclone, and increased relative humidity due to greater evaporation minus precipitation. Thus, unlike in the South Pacific, the North Pacific warming pattern involves surprisingly little coupled air-sea interaction, being shaped instead by forced atmospheric responses and clear-sky radiative feedbacks.