Estimates of wave height data for New Zealand waters by numerical modelling

Laing, Andrew K.

doi:10.1080/00288330.1993.9516554

Cited by 8 publications

(19 citation statements)

References 12 publications

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“…This is notably the case for in situ measurements such as wave-recording buoys and observations from ships in the rarely traversed waters of the Southern Ocean (Pickrill & Mitchell 1979;Reid & Collen 1983;Laing 1993). This 590 New Zealand Journal of Marine and Freshwater Research, 2003, Vol.…”

Section: Introductionmentioning

confidence: 99%

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Wave hindcast for the New Zealand region: Deep‐water wave climate

Gorman

Bryan

Laing

2003

New Zealand Journal of Marine and Freshwater Research

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The wave evolution model WAM (WAve Model) has been implemented for the New Zealand region and used to simulate the generation and propagation of deep-water waves over a 20-year period . The model extends to include the relevant generation areas of the south-west Pacific and Southern Oceans. Input winds for the model were derived from the European Centre for MediumRange Weather Forecasts (ECMWF). The resulting synthetic wave climatology will provide a valuable tool for researchers and coastal planners, as it will help fill gaps in the available wave information for New Zealand waters. In this paper the hindcasts are described, and comparisons are made with wave height data from the altimeters flown on the TOPEX/ Poseidon and ERS1 and ERS2 satellite missions. Long-term mean significant wave heights from the hindcast were generally 0.3-0.5 m lower than values from "buoy-equivalent" altimeter data throughout the comparison region (150°E-170°W, 60°S-20°S). Hindcast distributions of significant wave height occurrence matched satellite data at the lowest wave heights and above the peaks of the distributions, but tended to overestimate occurrence below the peak and underestimate the occurrence of the largest wave events. The hindcast was then used to characterise the wave climate of the New Zealand region. Some prominent features noted were the large mean heights (3.6 m) in the high latitudes of the Southern Ocean, associated with strong prevailing westerlies. North of this band, waves largely propagate towards the north-east, with diminishing mean heights, further attenuated by the blocking effect of the New Zealand landmasses. This results in mean wave heights of c. 2 m in offshore waters north-east of New Zealand. Annual cycles of mean wave height with a range of c. 1 m were identified throughout the region. These were found to have minima in summer (December/January), and either unimodal maxima in winter (June/July) for tropical and temperate latitudes, or bimodal maxima (May and August) in southern waters. Longer-term variations were also noted in the form of correlations with the El Niño/Southern Oscillation. Positive correlations (R +0.2) were found off the north-east coast of the North Island, indicating a moderate tendency for increased wave heights there during La Niña conditions, whereas negative correlations were found south and south-west of New Zealand (R -0.2), and in the Fiji/Vanuatu region (R +0.4), reflecting wave height enhancements in the El Niño phase.

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Section: Introductionmentioning

confidence: 99%

“…This model has then been applied to create a 20-year wave hindcast, simulating wave conditions throughout the years 1979-98. The study builds on previous work (Laing 1992;Laing 1993) in which a secondgeneration model was applied to the New Zealand region to produce a short (5 month) trial hindcast.…”

Section: Introductionmentioning

confidence: 99%

Wave hindcast for the New Zealand region: Deep‐water wave climate

Gorman

Bryan

Laing

2003

New Zealand Journal of Marine and Freshwater Research

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“…This limitation has overridden any necessity for additional sophistication in the wave modelling itself which a 3rd-generation model (e.g., Hasselmann et al 1988) may offer. In the present context inadequacies in results from the 2nd-generation model can almost always be traced to uncertainties in the wind fields (Laing 1993). The key difference between 2nd-and 3rd-generation models is in the way in which wave energy is redistributed throughout the wave spectrum by weakly nonlinear wave-wave interactions.…”

Section: Introductionmentioning

confidence: 99%

“…The wave generation model accounts for the generation and advection of wave energy, and also includes an approximate description of the non-linear process by which the wave energy in shorter-period waves is gradually transferred to longer periods. The area covered by the model is shown in Laing (1993) and extends c. 2000 km east and south of New Zealand. Grid points adjacent to the Canterbury Bight are shown in Fig.…”

Section: Modelling the Wave Climatementioning

confidence: 99%

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Synthesis of extreme wave climate for the Canterbury Bight, New Zealand

Macky

McKerchar

Laing³

et al. 2000

New Zealand Journal of Marine and Freshwater Research

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Numerical models of the marine wind field and wave generation offer a technique for estimating the severity of extreme wave events. Measured and modelled waves in the Canterbury Bight, New Zealand, were used to examine the hypothesis that extreme conditions can be more confidently estimated by modelling the wave climate over a decade than by analysing shorter measured records. The meteorological conditions causing high waves in the Canterbury Bight were examined by inspecting wind measurements at Christchurch Airport and wave buoy measurements made in 1983-85 near the Rakaia River mouth. Although the arrival of high waves was sometimes associated with wind changes at the airport, peak wave heights generally occurred at least several hours after such wind changes and were associated with south-westerly or southerly winds in the Bight and a depression south-east of the South Island. Wave conditions at the buoy site for 1980-89 were modelled using marine winds obtained from a global circulation model, running a wave generation model for the seas around New M98060 Received 25 August 1998; accepted 21 July 1999Zealand, and then applying a refraction model. The decade modelled included two El Niño events and one La Niña event, and the ocean wind climate should therefore have been reasonably representative of the long-term range of conditions. The model results were verified against the buoy measurements. Estimates of extreme wave heights were then made from 10 years of modelled record and also the measured buoy record. Application of the Gumbel distribution to the monthly maxima gave a significant wave height of 9.5 m for the wave event with an annual exceedance probability of 1 in 50. Model predictions indicate that the most severe waves arrive in the Bight from due south. Estimates of extremes from the measurements and model hindcast were close, indicating that the hindcast represents a population of events similar to those measured.

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Regional influence of climate patterns on the wave climate of the southwestern Pacific: The New Zealand region

2016

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This work investigates how the wave climate around New Zealand and the southwest Pacific is modulated by the Pacific Decadal Oscillation (PDO), El Niño-Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), Zonal Wave-number-3 Pattern (ZW3), and Southern Annular Mode (SAM) during the period 1958-2001. Their respective climate indices were correlated with modeled mean wave parameters extracted from a 45 year wave hindcast carried out with the WAVEWATCH III model using the wind and ice fields from the ERA-40 reanalysis project. The correlation was performed using the Pearson's correlation coefficient and the wavelet spectral analysis. Prior to that, mean annual and interannual variabilities and trends in significant wave height (H s ) were computed over 44 years . In general, higher annual and interannual variabilities were found along the coastline, in regions dominated by local winds. An increasing trend in H s was found around the country, with values varying between 1 and 6 cm/decade at the shoreline. The greatest H s trends were identified to the south of 488S, suggesting a relationship with the positive trend in the SAM. Seasonal to decadal time scales of the SAM strongly influenced wave parameters throughout the period analyzed. In addition, larger waves were observed during extreme ENSO and IOD events at interannual time scale, while they were more evident at seasonal and intraseasonal time scales in the correlations with the ZW3. Negative phases of the ZW3 and ENSO and positive phases of the IOD, PDO, and SAM resulted in larger waves around most parts of New Zealand.

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Estimates of wave height data for New Zealand waters by numerical modelling

Cited by 8 publications

References 12 publications

Wave hindcast for the New Zealand region: Deep‐water wave climate

Wave hindcast for the New Zealand region: Deep‐water wave climate

Synthesis of extreme wave climate for the Canterbury Bight, New Zealand

Regional influence of climate patterns on the wave climate of the southwestern Pacific: The New Zealand region

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