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

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.

Surface Albedo Feedback, Seasonal Heat Storage and Meridional Heat Transport Determine the Seasonality of Recent Warming in Antarctica

“…Additional carbon dioxide (CO 2 ) forcing (greenhouse effect) leads to less longwave radiation escaping from the Earth (Myhre et al, 2013;Shmithüsen et al, 2015); Planck feedback (surface warming leading to more longwave radiation moving upward; Goosse et al, 2018;Pithan & Mauritsen, 2014;Stuecker et al, 2018); cloud feedback (more clouds may lead to either less solar radiation going downward or less longwave radiation going upward; Ceppi & Nowack, 2021;Lu & Cai, 2009;Huang et al, 2017); and lapse rate feedback (the sensitivity of outgoing longwave radiation at the top of atmosphere (TOA) to the vertical tropospheric temperature structure; Boeke et al, 2020;Pithan & Mauritsen, 2014) may not be the triggers for surface warming in Antarctica after 2016, as they exhibit passive changes (no sudden increase in CO 2 concentration). Clark et al (2021) and Dai (2023b) proposed a possible mechanism through which remote forcing influences local skin temperature. Here, remote forcing is defined as atmospheric blocking events at mid-high latitudes that influence the Arctic surface air temperature via horizontal advection and/or convection.…”

“…Clark et al. (2021) and Dai (2023b) proposed a possible mechanism through which remote forcing influences local skin temperature. Here, remote forcing is defined as atmospheric blocking events at mid‐high latitudes that influence the Arctic surface air temperature via horizontal advection and/or convection.…”