Föhn-Induced Melting over Larsen C Modulated by Atmospheric River Shape, Direction, and Landfall Location

April 12, 2026

A new paper titled “Föhn-Induced Melting over Larsen C Modulated by Atmospheric River Shape, Direction, and Landfall Location” has been published in Nature Communications. The study was led by Xun (Jerry) Zou (SIO), with co-authors Penny M. Rowe (NorthWest Research Associates), Irina V. Gorodetskaya (CIIMAR), Andrew Orr (British Antarctic Survey), David H. Bromwich (The Ohio State University), Dan Lubin (SIO), Matthew A. Lazzara (University of Wisconsin–Madison), Zhenhai Zhang (SIO), Brian Kawzenuk (SIO), Jonathan D. Wille (ETH Zürich), Jason M. Cordeira (SIO), Nicolaj Hansen (Danish Meteorological Institute), Jinxi Li (Chinese Academy of Sciences), Pu Gan (Chinese Academy of Sciences), and F. Martin Ralph (SIO).

This international collaborative work was supported by the National Science Foundation (OPP-2229392 and OPP-2331992) and highlights the importance of atmospheric river (AR) characteristics in influencing ice surface conditions, particularly through interactions with other weather systems. The study also contributes to CW3E’s Strategic Plan (Atmospheric Rivers and Extreme Precipitation Research, Prediction, and Applications) and advances AR science in polar regions.

In recent decades, the Antarctic Peninsula has experienced record-high temperatures driven by ARs and föhn winds, although not all AR events produce widespread warming over the Larsen C Ice Shelf. Using high-resolution simulations, we identify four distinct AR shapes associated with föhn-induced surface warming over the Larsen C Ice Shelf: zonal-perpendicular, zonal-like, convex, and concave. Zonal-like ARs, linked to coupled low–high-pressure systems, and convex ARs, associated with blocking highs, produce strong and widespread föhn warming, primarily affecting the northern and southern sectors, respectively. In contrast, zonal-perpendicular and concave ARs lead to weaker warming due to lower AR intensity or curvature effects. Surface warming is mainly controlled by radiation and heat fluxes, with moisture and clouds playing an important role. As ARs intensify under climate change, their interaction with blocking highs and föhn winds may increasingly influence the stability of Antarctic ice shelves (Fig. 1).

Stronger ARs in the future are likely to drive more frequent and intense surface warming over Antarctica, along with increased sea ice loss. Along the coast, small-scale weather processes play a key role but are often poorly represented in global climate models. These processes are critical for understanding how ice shelves and sea ice will respond, with important implications for Antarctic ice loss and global sea-level rise. This highlights the need for higher-resolution models that better capture interactions among the atmosphere, ocean, and ice.

Figure 1. Three-dimensional trajectories of temperature and moisture for two representative AR events. Nine-hour backward trajectories that initialized 2 m above the Larsen C Ice Shelf (LCIS) surface of (a,c) zonal-perpendicular and (b,d) convex events, occurring in Dec 2008 and Feb 2013 respectively, and based on PWRF simulations. (a,c) trajectories showing temperature (°C) and water vapor mixing ratio changes (g kg^-1) from 00Z to 09Z on 3 Dec. (b,d) as (a,c) but from 00Z to 09Z on 3 Feb. LCIS in (a) refers to the Larsen C Ice Shelf. All values are archived in the source data. From Figure 6 in Zou et al. (2026).

Citation:

Zou, X., Rowe, P. M., Gorodetskaya, I. V., Orr, A., Bromwich, D. H., Lubin, D., Lazzara, M. A., Zhang, Z., Kawzenuk, B., Wille, J. D., Cordeira, J. M., Hansen, N., Li, J., Gan, P., & Ralph, F. M. (2026). Föhn-induced melting over Larsen C modulated by atmospheric river shape, direction and landfall location. Nature Communications. https://doi.org/10.1038/s41467-026-71359-2