Role of Horizontal Heat Advection in Arctic Surface Warming During Early Spring

• Published in: Geophysical Research Letters
• Main Author: Haijin Dai
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2023
• Subjects: Arctic amplification; atmospheric blocking; spring Arctic warming; Geophysics. Cosmic physics; QC801-809; Arctic
• Online Access: https://doi.org/10.1029/2023GL103234; https://doaj.org/article/5b6f0087b07042a2a81011302bd693c8

Abstract Reanalysis data and numerical model are employed to uncover the mechanisms of spring (March–April) Arctic surface warming. Different from other seasons, little additional solar radiation absorption or seasonal heat storage release contributes to Arctic surface warming in spring. Both observation and numerical results suggest that horizontal heat advection dominates Arctic surface air warming. However, horizontal advection originates from lower latitudes instead of local energy redistribution as in other seasons. Furthermore, Arctic warming weakens the meridional potential vorticity gradient, which strengthens the synoptic atmospheric blocking event. As a result, more warm (cold) air is transported to higher (lower) latitudes along the edge of high pressure, which is an accumulation of atmospheric blocking events. The results suggest that anomalous meridional heat transport plays more important roles in Arctic surface warming when the anomalous radiative forcing is weak. Without being absorbed by the ocean, additional available energy induces strong Arctic springtime surface warming.