Recent Change in Sea Level Along the Coast of New Zealand Using Tide Gauge and XTRACK Coastal Altimetry Data

Abstract

Abstract The rise in sea level along the coasts of New Zealand has accelerated in recent decades due to the impact of climate change. Determining the effects of these changes on the coastal regions is critical for their sustainability. In order to gain insight into these impacts, the present study aimed to analyze sea level changes using satellite altimetry and tide gauge data from 11 tide gauge stations along the New Zealand coast between 1993 and 2022, as well as XTRACK data processed with the coastal altimetry approach to minimize the effects of classical altimetry near coasts. The least-squares parameter estimation method was used to analyze the data and determine annual and semi-annual seasonal effects. The results showed that the sea level trend is rising in both methods; for instance, 4.2 ± 0.6 mm/yr from the tide gauge data and 3.6 ± 0.8 mm/yr from the XTRACK data at the WELLINGTON HARBOUR tide gauge. The results of this study demonstrate the importance of closely monitoring the impacts of sea level rise on the coastal regions of New Zealand to ensure their long-term sustainability. The results also highlight the utility of using multiple data sources and methods to provide a comprehensive understanding of these changes.