Environmental Reporting Data - Page 14

The ocean waters surrounding New Zealand vary in temperature from north to south. They interact with heat and moisture in the atmosphere and affect our weather. Long-term changes and short-term variability in sea-surface temperatures can affect marine processes, habitats, and species. Some species may find it hard to survive in changing environmental conditions.

This layer shows annual average sea surface temperature for 2010 as part of the data series for years 1993 to 2013.

NIWA’s sea-surface temperature archive is derived from the Advanced Very High Resolution Radiometer (AVHRR) satellite data it receives from the National Oceanic and Atmospheric Administration. The archive provides high spatial (approximately 1km) and high temporal (approximately 6-hourly in cloud-free locations) resolution estimates of sea-surface temperatures over the New Zealand region, dating from January 1993. Uddstrom and Oien (1999) and Uddstrom (2003) describe the methods used to derive and validate the data.

This dataset relates to the "Annual average sea-surface temperature" measure on the Environmental Indicators, Te taiao Aotearoa website.

Geometry: grid
Unit: degrees Celsius

Further information can be found in:
Uddstrom, MJ (2003). Lessons from high-resolution satellite SSTs. Bulletin of the American Meteorological Society, 84(7), 896–897.
Uddstrom, MJ, & Oien, NA (1999). On the use of high resolution satellite data to describe the spatial and temporal variability of sea surface temperatures in the New Zealand region. Journal of Geophysical Research (Oceans) 104, chapter 9, 20729–20751.

"The pressure from animal and plant pests is one of the biggest threats to biodiversity in the land environment. Pest predators (such as stoats and possums) eat eggs, birds, lizards, insects, and snails. Other animal pests (such as deer and goats) damage and kill trees and other plants and can compete with indigenous animals for the plants’ fruit and seed. Pest plants can out-grow the local vegetation. All these activities can dramatically change both our indigenous and agricultural environments.

This data set relates to the "Land pests" measure on the Environmental Indicators, Te taiao Aotearoa website."

Interpolated PED values at 30 regionally representative sites.
Soil moisture is vital for plant growth. When plants cannot access the water they need, growth is reduced, affecting crops and food for livestock, and native biodiversity. Over a sustained period, a drought can have significant social and economic costs, particularly for rural communities.
Potential evapotranspiration deficit (PED) can be thought of as a drought index. It is the difference between how much water could potentially be lost from the soil through evapotranspiration and how much is actually available. When PED is high, plants do not have the full amount of water available they need for growth. PED is measured in growing seasons (the 12 months from 1 July to 30 June of the following year. Data covers each of the growing seasons from 1 July 1972, with the last growing season in the series ending on 30 June 2016. 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.

The number of exotic species observed in New Zealand's monitored ports of first entry for international vessels

Nitrogen is an essential nutrient for plant growth. It occurs naturally in the environment but is added in agricultural processes (typically as fertiliser) to boost production. Although much of the applied nitrogen is taken up by plants, livestock waste returns a considerable amount to the soil. Nitrate formed from this waste easily drains (leaches) from the soil before plants can absorb it, and it can enter waterways, potentially harming ecosystems.

This dataset relates to the "Trends in nitrogen leaching from agricultural activities" measure on the Environmental Indicators, Te taiao Aotearoa website.

Sea-level rise is a consequence of climate change. Increases in global temperature cause ocean waters to expand, and glaciers and ice sheets to melt into oceans. Sea-level rise affects estuaries, coastal wetlands, and intertidal and sub-tidal habitats and species. The increased likelihood of coastal erosion from sea-level rise presents a risk for seaside communities and their infrastructure, and for the marine environment itself, from increased suspended sediments.
This dataset relates to the "Coastal sea-level rise" measure on the Environmental Indicators, Te taiao Aotearoa website.

Daily rainfall values for 30 representative sites from 1960–2016.
Rain is vital for life – it supplies the water we need to drink and to grow our food, keeps our ecosystems healthy, and supplies our electricity. New Zealand’s mountainous terrain and location in the roaring forties mean rainfall varies across the country. Changes in rainfall amount or timing can significantly affect agriculture, energy, recreation, and the environment. For example, an increase or decrease of rainfall in spring can have marked effects on crops or fish populations.
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.

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 a wave-height threshold for each year from 2008 to 2015 in coastal regions.
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.
This dataset relates to the number of extreme wave events exceeding the four metre threshold in coastal regions.

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.

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 a wave-height threshold for each year from 2008 to 2015 in coastal regions.
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.
This dataset relates to the number of extreme wave events exceeding the six metre threshold in coastal regions.