Satellite radar altimeter‐derived sea surface heights (SSH) are in error in coastal regions due, in part, to the complex nature of echoes returned from rapidly varying land and sea surfaces. This paper presents improved altimeter‐derived SSH results in Australian coastal regions using the waveform retracking technique, which reprocesses the waveform data through a “coastal retracking system”. The system, based upon a systematic analysis of satellite radar altimeter waveforms around Australia, improves SSH data from several retrackers depending on the waveforms' characteristics. Central to the system is the use of two techniques: the least squares fitting and the threshold retracking algorithms. To overcome the problem of fading noise, the fitting algorithm has been developed to include a weighted iterative scheme. The retrackers include five fitting models and the threshold method with varying threshold levels. A waveform classification procedure has also been developed, which enables the waveforms to be sorted and then retracked by an appropriate retracker. Two cycles of 20‐Hz waveform data from ERS‐2 have been reprocessed using this system to obtain the improved SSH estimates. Using the AUSGeoid98 gravimetric geoid model as a quasi‐independent reference, the system improves SSH estimates from beyond ∼22 km to beyond ∼5 km from the coastline.

It is broadly acknowledged that the precision of satellite-altimeter-measured instantaneous sea surface heights (SSH) is lower in coastal regions than in open oceans, due partly to contamination of the radar return from the coastal sea-surface state and from land topography. This study investigates the behavior of ERS-2 and POSEIDON altimeter waveform data in coastal regions and estimates a boundary around Australia's coasts in which the altimeter range may be poorly estimated by on-satellite tracking software. Over one million 20 Hz ERS-2 (March to April 1999) and POSEIDON (January 1998 to January 1999) radar altimeter waveform data were used over an area extending 350 km offshore Australia. The DS759.2 (5'resolution) ocean depth model and the GSHHS (0.2 km resolution) shoreline model were used together to define the coastal regions. Using the 50% threshold retracking points as the estimates of expected tracking gate, we determined that the sea surface height is contaminated out to maximum distance of between about 8 km and 22 km from the Australian shoreline for ERS-2, depending partly on coastal topography. Using the standard deviation of the mean waveforms as an indication of the general variability of the altimeter returns in the Australian coastal region shows obvious coastal contamination out to about 4 km for both altimeters, and less obvious contamination out to about 8 km for POSEIDON and 10 km for ERS-2. Therefore, ERS-2 and POSEIDON satellite altimeter data should be treated with some caution for distances less than about 22 km from the Australian coast and probably ignored altogether for distances less than 4 km.

A changing climate may increase the frequency or intensity of natural hazards, resulting in increased infrastructure damage. The paper will describe how risk-based approaches are well suited to optimising climate adaptation strategies related to the construction, design, operation, and maintenance of built infrastructure. Climate adaptation engineering involves estimating the risks, costs, and benefits of climate adaptation strategies and assessing at what point in time climate adaptation becomes economically viable. Stochastic methods are used to model infrastructure performance, risk reduction, and effectiveness of adaptation strategies, exposure, and costs. These concepts will be illustrated with recent research on risk-based life-cycle assessments of climate adaptation strategies for Australian housing subject to extreme wind events. This will pave the way for more efficient and resilient infrastructure, and help future proof new and existing infrastructure to a changing climate