From Sea to Summit: Investigating the Explicit Role of SST Increase for Regional and High-Altitude Climates in New Zealand

Kropač E, Mölg T, Cullen NJ (2025)

Publication Language: English

Publication Type: Journal article

Publication year: 2025

Journal

Journal of Geophysical Research: Atmospheres American Geophysical Union (AGU)

Book Volume: 130

Article Number: e2025JD043572

Journal Issue: 15

URI: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025JD043572

DOI: 10.1029/2025JD043572

Open Access Link: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025JD043572

Abstract

The oceans around New Zealand are regional warming hotspots where sea surface temperature (SST) is rising much faster than the global average. This study uses a sensitivity experiment with a regional atmospheric model to investigate how ocean warming over the past decade (2010–2020) has influenced New Zealand's climate at different spatial scales, with particular attention to the highly sensitive alpine regions of the Southern Alps. The approach addresses the effects of an isolated SST increase, explicitly excluding broader systemic changes associated with global warming. Results suggest that rising SSTs have driven widespread thermodynamic responses, including increases in near-surface air temperature and humidity, particularly in autumn and summer. These responses have most likely affected circulation dynamics—such as changes in wind fields and moisture transport—that have modified the mesoscale flow regime near the Southern Alps, reshaping precipitation patterns and reducing foehn effects in the eastern lowlands. The dynamic responses, however, remain subject to uncertainty. Crucially, the impacts of the SST increase extend into the alpine environment, where surface warming is amplified and snowfall is reduced. Consequently, high-elevation climate regimes have shifted toward warmer and more humid conditions, contributing to greater rainfall dominance and potentially accelerated glacial melt. This study provides a process-based understanding of the influence of SST changes on both regional and high-altitude climate in New Zealand. The findings emphasize the potential for continued ocean warming to exacerbate high-elevation climate shifts and glacier retreat, with substantial implications for regional hydrology, ecosystems, and human activities.

Authors with CRIS profile

Thomas Mölg Professur für Geographie

Related research project(s)

Das Potenzial von corallinen Algen als Indikator des Klimas in der Südlichen Hemisphäre und für die Evaluierung von globalen Klimamodellen: eine Fallstudie zu Neuseeland - Fortsetzungsprojekt Oct. 1, 2024 - Sept. 30, 2026

Involved external institutions

University of Otago NZ New Zealand (NZ)

How to cite

APA:

Kropač, E., Mölg, T., & Cullen, N.J. (2025). From Sea to Summit: Investigating the Explicit Role of SST Increase for Regional and High-Altitude Climates in New Zealand. Journal of Geophysical Research: Atmospheres, 130(15). https://doi.org/10.1029/2025JD043572

MLA:

Kropač, E., Thomas Mölg, and N. J. Cullen. "From Sea to Summit: Investigating the Explicit Role of SST Increase for Regional and High-Altitude Climates in New Zealand." Journal of Geophysical Research: Atmospheres 130.15 (2025).

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