Trends in number of days with a maximum gust in the 99th percentile, 1972–2016

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5167
10
Added
12 Oct 2017

This dataset was first added to MfE Data Service on 12 Oct 2017.

Trends in number of days with a maximum gust in the 99th percentile, 1972–2016. The number of days with a maximum gust in the 99th percentile provides information on the frequency of extreme wind events. Percentiles are obtained from all available daily maximum wind gust data. On average, the 99th percentile daily maximum wind gust will be exceeded on approximately 3.6 days per year. Therefore, annual counts higher than this indicate more days than usual with very strong wind gusts recorded; annual counts lower than 3.6 indicate fewer strong wind gust days than usual. By using a percentile threshold we can identify events that are extreme for a particular location. Some places are naturally subject to stronger winds than others, so vegetation can become ‘wind-hardened’ and may have a higher tolerance to high wind gusts (eg a 100 km/hr wind gust may be damaging at one location, but not at another). Using a relative threshold accounts for these differences and better captures extreme wind gust occurrences. The highest maximum gust per year and the average annual highest maximum wind gust both provide information on the magnitude of extreme wind events.
Steady wind can be an important resource, but strong gusts can damage property, topple trees, and disrupt transportation, communications, and electricity. Extreme wind events can occur with frontal weather systems, around strong convective storms such as thunderstorms, and with ex–tropical cyclones. Projections indicate climate change may alter the occurrence of extreme wind events, with the strength of extreme winds expected to increase over the southern half of the North Island and the South Island, especially east of the Southern Alps, and decrease from Northland to Bay of Plenty. Monitoring can help us gauge the potential of, and prepare for, such events.
Trend direction was assessed using the Theil-Sen estimator and the Two One-Sided Test (TOST) for equivalence 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 89423
Data type Table
Row count 30
Services Web Feature Service (WFS), Catalog Service (CS-W), data.govt.nz Atom Feed

Wildfire risk, 1997 - 2019, state

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Creative Commons Attribution 4.0 International

You may use this work for commercial purposes.

You must attribute the creator in your own works.

547
8
Added
14 Oct 2020

This dataset was first added to MfE Data Service on 14 Oct 2020.

DATA SOURCE: National Institute for Water and Atmospheric Research (NIWA)
[Technical report available at www.mfe.govt.nz/publications/environmental-reporti... and www.mfe.govt.nz/publications/environmental-reporti...]

Adapted by Ministry for the Environment and Statistics New Zealand to provide for environmental reporting transparency

Dataset used to develop the "Wildfire indicator [available at www.stats.govt.nz/indicators/wildfire-risk]

This indicator measures fire danger using the New Zealand Fire Danger Rating at 30 sites around New Zealand from 1997 to 2019, although not all sites start at 1997. We report on the number of days per year with ‘very high and extreme’ (VH+E) fire danger for each of these sites.

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 105046
Data type Table
Row count 17280
Services Web Feature Service (WFS), Catalog Service (CS-W), data.govt.nz Atom Feed

Wildfire risk, 1997 - 2019, trend

Licence

Creative Commons Attribution 4.0 International

You may use this work for commercial purposes.

You must attribute the creator in your own works.

1285
10
Added
14 Oct 2020

This dataset was first added to MfE Data Service on 14 Oct 2020.

DATA SOURCE: National Institute for Water and Atmospheric Research (NIWA)
[Technical report available at www.mfe.govt.nz/publications/environmental-reporti... and www.mfe.govt.nz/publications/environmental-reporti...]

Adapted by Ministry for the Environment and Statistics New Zealand to provide for environmental reporting transparency

Dataset used to develop the "Wildfire indicator [available at www.stats.govt.nz/indicators/wildfire-risk]

This indicator measures fire danger using the New Zealand Fire Danger Rating at 30 sites around New Zealand from 1997 to 2019, although not all sites start at 1997. We report on the number of days per year with ‘very high and extreme’ (VH+E) fire danger for each of these sites, and trends over time.

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 105047
Data type Table
Row count 56
Services Web Feature Service (WFS), Catalog Service (CS-W), data.govt.nz Atom Feed
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