Heard Island sea level data Voyage 1 and Voyage 2 2025/26

Published: 2026-05-11

This dataset includes water levels obtained from two locations using different methods at Heard Island between 19 October 2025 and 18 January 2026 (inclusive). The dataset covers the period between Voyage 1 and Voyage 2 HIMI campaigns during the 2025/26 Antarctic season. Method 1 water levels were obtained via a pressure sensor mounted to a seabed frame temporarily deployed at approximately 5-6 metres water depth in Atlas Cove (bottom pressure). Method 2 water levels were obtained from GNSS (Global Navigation Satellite Systems) data collected at Magnet Point, with preliminary processing using a GNSS interferometric reflectometry (GNSS-IR) approach. The distance between the two installations is approximately 7 kilometres. Atmospheric pressure used in deriving water level from the pressure gauge was obtained from an Automatic Weather Station co-located with the GNSS-IR system. This dataset is a collaborative effort between the Australian Antarctic Data Centre (AADC) bathymetric mapping project (AAP5198), the Maritime Geospatial Warfare Unit of the Royal Australian Navy (RAN), and the Southern Ocean Sea Level Monitoring Project (AAS4626).