Impacts of the North Atlantic biases on the upper troposphere/lower stratosphere over the extratropical North Pacific

• Published in: npj Climate and Atmospheric Science
• Main Authors: Rajat Joshi, Rong Zhang
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Portfolio 2023
• Subjects: Environmental sciences; GE1-350; Meteorology. Climatology; QC851-999; North Atlantic
• Online Access: https://doi.org/10.1038/s41612-023-00482-4; https://doaj.org/article/1d4c667be66e483191ff77461a149714

Abstract The winter upper troposphere/lower stratosphere temperature/vertical motion response over the extratropical North Pacific induced by North Atlantic changes is not well understood. Here, using robust diagnostic calculations conducted in a fully coupled high-resolution climate model, we correct the North Atlantic ocean circulation biases and show that during wintertime, the North Atlantic cold surface temperature biases lead to a warmer upper troposphere/lower stratosphere over the extratropical North Pacific. In the upper troposphere/lower stratosphere over the extratropical North Pacific, this winter warming temperature response is linked to the vertical motion response through a simple leading order thermodynamic relationship between changes in the horizontal advection and adiabatic heating. The upper troposphere/lower stratosphere vertical motion response, which is also associated with the North Atlantic induced Walker circulation response over the tropical North Pacific, can provide a rough estimation of the upper troposphere/lower stratosphere warming response over the extratropical North Pacific.