Wave forecast investigations on downscaling, source terms, and tides for Aotearoa New Zealand

<p>This study evaluates the effects of downscaling, source terms, and tidal interactions on numerical wave forecasts in Aotearoa New Zealand. We utilised a set of three nested domains (from global to regional scale) to examine significant wave height (Hs), first-order mean period (Tm01), and p...

Full description

Saved in:
Bibliographic Details
Main Authors: R. Santana, R. Gorman, E. Lane, S. Moore, C. Bosserelle, G. Reeve, C. Rautenbach
Format: Article
Language:English
Published: Copernicus Publications 2025-08-01
Series:Geoscientific Model Development
Online Access:https://gmd.copernicus.org/articles/18/4877/2025/gmd-18-4877-2025.pdf
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:<p>This study evaluates the effects of downscaling, source terms, and tidal interactions on numerical wave forecasts in Aotearoa New Zealand. We utilised a set of three nested domains (from global to regional scale) to examine significant wave height (Hs), first-order mean period (Tm01), and peak wave direction at two coastal locations, Banks Peninsula and Baring Head. Downscaling markedly improved forecast accuracy at Baring Head, a tidally constricted region, reducing Hs forecast error by 28 %. However, improvements at Banks Peninsula were minimal, likely due to its open-coast characteristics, which are adequately represented even by lower-resolution models. This variability was also evident in the Tm01 predictions, with notable improvements in bias reduction through model downscaling, particularly at Baring Head. Using default source term 6 (ST6) parameters generally improved Hs predictions on the west coast but worsened them on the east, indicating a geographical dependency in model performance. Tidal forcing had a small impact on the overall forecast skill, and its impact was mostly noticed at Baring Head, where tides force large variability. However, the tidally driven wave model showed smaller 12 <span class="inline-formula">h</span> variability compared to observations. The study underscores the importance of tailored modelling approaches that consider local geographical and hydrodynamic conditions to optimise wave forecasting.</p>
ISSN:1991-959X
1991-9603