Trends in ocean acidification, 1998–2016

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Creative Commons Attribution 4.0 International

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1365
10
Added
14 Oct 2017

This dataset was first added to MfE Data Service on 14 Oct 2017.

The pH of New Zealand subantarctic waters is calculated from pCO2 (dissolved carbon dioxide) and alkalinity measurements using refitted Mehrbach constants (see Mehrbach et al, 1973; Dickson & Millero, 1987), and in-situ temperature taken from the Munida time-series transect off the Otago coast. Measurements of pCO2 are taken every two months.
The Munida transect, in the subantarctic waters off Otago, is the Southern Hemisphere’s longest-running record of pH measurements (NIWA, 2015).
Trends were assessed using linear regression at the 95% confidence level.
More information on this dataset and how it relates to our Environmental reporting indicators and topics can be found in the attached data quality pdf.

Table ID 89462
Data type Table
Row count 3
Services Web Feature Service (WFS), Catalog Service (CS-W), data.govt.nz Atom Feed

Ocean acidification, 1998–2016

Licence

Creative Commons Attribution 4.0 International

You may use this work for commercial purposes.

You must attribute the creator in your own works.

778
14
Added
14 Oct 2017

This dataset was first added to MfE Data Service on 14 Oct 2017.

The pH of New Zealand subantarctic waters is calculated from pCO2 (dissolved carbon dioxide) and alkalinity measurements using refitted Mehrbach constants (see Mehrbach et al, 1973; Dickson & Millero, 1987), and in-situ temperature taken from the Munida time-series transect off the Otago coast. Measurements of pCO2 are taken every two months.
The Munida transect, in the subantarctic waters off Otago, is the Southern Hemisphere’s longest-running record of pH measurements (NIWA, 2015).
More information on this dataset and how it relates to our Environmental reporting indicators and topics can be found in the attached data quality pdf.

Table ID 89461
Data type Table
Row count 660
Services Web Feature Service (WFS), Catalog Service (CS-W), data.govt.nz Atom Feed

Oceanic extreme waves (2008–15)

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Creative Commons Attribution 3.0 New Zealand

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1121
7
Added
19 Oct 2016

This dataset was first added to MfE Data Service on 19 Oct 2016.

Extreme wave indexes estimate the occurrence of extreme wave events in coastal and oceanic waters. Extreme wave indexes estimate the number of times a significant wave height exceeds one of three threshold values for at least 12 hours in 24 marine regions. The three wave-height thresholds are four metres, six metres, and eight metres.
This indicator estimates the exceedances of wave-height thresholds for each year from 2008 to 2015 in oceanic areas around New Zealand.
Significant wave height is a measure of the ‘typical’ wave height in a place over a time period. It is four times the standard deviation of the water surface if, for example, you were to measure water moving up and down a jetty piling for an hour. The largest individual wave will typically have a height around twice the significant wave height.
We use three wave-height thresholds because of the regional variation in extreme wave events. In general, the north experiences less exposure to consistently strong winds, and the waves generated by them, than the south. Four-metre tall waves are considered extreme in the northern-most parts of New Zealand but are more common in the south. For the southern-most parts of New Zealand, eight-metre waves better represent extreme wave events.

Table ID 53477
Data type Table
Row count 18
Services Web Feature Service (WFS), Catalog Service (CS-W), data.govt.nz Atom Feed

Coastal extreme waves (2008–15)

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Creative Commons Attribution 3.0 New Zealand

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You must attribute the creator in your own works.

1018
8
Added
19 Oct 2016

This dataset was first added to MfE Data Service on 19 Oct 2016.

Extreme wave indexes estimate the occurrence of extreme wave events in coastal and oceanic waters. Extreme wave indexes estimate the number of times a significant wave height exceeds one of three threshold values for at least 12 hours in 24 marine regions. The three wave-height thresholds are four metres, six metres, and eight metres.
This indicator estimates the exceedances of wave-height thresholds for each year from 2008 to 2015 in coastal areas.
Significant wave height is a measure of the ‘typical’ wave height in a place over a time period. It is four times the standard deviation of the water surface if, for example, you were to measure water moving up and down a jetty piling for an hour. The largest individual wave will typically have a height around twice the significant wave height.
We use three wave-height thresholds because of the regional variation in extreme wave events. In general, the north experiences less exposure to consistently strong winds, and the waves generated by them, than the south. Four-metre tall waves are considered extreme in the northern-most parts of New Zealand but are more common in the south. For the southern-most parts of New Zealand, eight-metre waves better represent extreme wave events.

Table ID 53476
Data type Table
Row count 54
Services Web Feature Service (WFS), Catalog Service (CS-W), data.govt.nz Atom Feed

Ocean storms (1979–2015)

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Creative Commons Attribution 3.0 New Zealand

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380
9
Added
14 Oct 2016

This dataset was first added to MfE Data Service on 14 Oct 2016.

The ocean storm index estimates the number of days in a year when wind speeds exceed gale and storm force on the Beaufort Scale. In a gale, sea conditions are rough and waves can be over six metres high. In a storm, waves can be over 10 metres high. To put this into context, on land a near gale would make walking difficult, and a storm would cause some damage to roofs, chimneys, and trees. Climate change could lead to changes in the frequency and intensity of storms. More frequent and intense storms will likely be a stressor for habitats and species.
The ocean storm index estimates the number of days that wind speeds exceed gale and storm force on the Beaufort Scale. The Beaufort Scale is a widely used international classification that rates sea conditions from 0 (calm) to 12 (hurricane). We report on estimated wind speeds broken down to:
- gales – measure 8 on the scale, have rough sea conditions with wind speeds of approximately 62–74 km per hour and wave heights of 5.5 metres
- storms – measure 10 on the scale, have wind speeds of approximately 89–102 km per hour and wave heights of 9–11.5 metres (McDonald & Parsons, 2016)

Table ID 53465
Data type Table
Row count 74
Services Web Feature Service (WFS), Catalog Service (CS-W), data.govt.nz Atom Feed

Acidity (pH) of subantarctic waters east of New Zealand (1998–2014)

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Creative Commons Attribution 3.0 New Zealand

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696
18
Added
28 Sep 2015

This dataset was first added to MfE Data Service on 28 Sep 2015.

Ocean acidification, measured by the reduction in sea water pH, is mainly caused by oceans absorbing and storing carbon dioxide from the atmosphere. Ocean acidification affects marine species in various ways. The growth and survival rates of some shell-building species are affected because they struggle to build their shells. The behaviour and physiology of some fish is also affected. This could influence marine ecosystems and commercial, customary, and recreational fishing or harvesting.
This dataset relates to the "Ocean acidification" measure on the Environmental Indicators, Te taiao Aotearoa website.

Table ID 52522
Data type Table
Row count 588
Services Web Feature Service (WFS), Catalog Service (CS-W), data.govt.nz Atom Feed