World Data - Page 8

Note: Metadata relates to the mosaicked imagery. This layer has been provided to enable users to explore coverage and capture dates of the imagery. To enquire about ordering the imagery, please e-mail lucas[at]mfe.govt.nz.

This imagery is a 15m, six-band multispectral, cloud-minimised mosaic of Landsat 8 satellite scenes over mainland New Zealand made from scenes captured late-2014/early-2015.

"Water clarity is a measure of underwater visibility in rivers and streams and can vary due to differences in land use, climate, elevation, and geology. Water clarity can be reduced by the presence of fine particles like silt, mud or organic material in the water. This affects the habitat and feeding of aquatic life like fish and aquatic birds. Water clarity is an important indicator of the health of a waterway, and is also a consideration for recreational activities like swimming and wading.
This dataset relates to the ""Geographic pattern of river water clarity"" measure on the Environmental Indicators, Te taiao Aotearoa website. "

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 2012 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 New Zealand River Environment Classification (REC) organises information about the physical characteristics of New Zealand's rivers. Individual river sections are mapped according to physical factors such as climate, source of flow for the river water, topography, and geology, and catchment land cover eg, forest, pasture or urban. Sections of river that have similar ecological characteristics can then be grouped together, no matter where they are.

This information is mapped for New Zealand's entire river network - over 425,000 kilometres of river. Different types of rivers respond differently to the pressures placed on them - the REC can be used to highlight the most appropriate management tools and approaches to reduce these pressures for each river type. Information from the classification is used to develop policy, assess the environment, and report on the quality of river water.

Stream order is the numerical position of a tributary or section of a river within the entire network. Headwater streams are assigned a stream order of 1. When two tributaries of the same stream order meet, the order increments by one for the next section downstream. However, if two sections meet where one section has higher order than the other, the next section downstream has the same order as the highest upstream section.

The User Guide is available from data.mfe.govt.nz/document/123-rec-user-guide-2010/ . Additional metadata can be found at www.mfe.govt.nz/publications/ser/metadata/env-clas... .

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 sea-surface temperature difference from normal for 2013 as part of the data series for years 1993 to 2013. "Normal" is defined as the average sea-surface temperature for 1993–2013.

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: percent

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.

Note: Metadata relates to the mosaicked imagery. This layer has been provided to enable users to explore coverage and capture dates of the imagery. To enquire about ordering the imagery, please e-mail lucas[at]mfe.govt.nz.

This imagery is 22m, three-band multispectral, cloud-minimised mosaics of Deimos-1 and UK-DMC-2 satellite scenes over mainland New Zealand captured late-2009/early-2010.

The imagery is only available to NZ Crown agencies.

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 regions 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.
This dataset relates to the number of extreme wave events exceeding the four metre threshold in oceanic regions.

River flow is the quantity of water passing a point over a certain time. Each river or stream has its own natural flow characteristics, such as peak flows following rain or high spring flows from snow melt. Overall, this affects how much water is available for irrigation, drinking water, hydroelectricity generation, and recreational activities. River flows also influence a waterway’s physical form, habitat, and ecological processes like migration, spawning, and food supply for aquatic life.

This dataset relates to the "The geographic pattern of river flows" measure on the Environmental Indicators, Te taiao Aotearoa website.

"Freshwater plant and animal pests can have significant negative impacts on ecosystem health by reducing indigenous biodiversity through predation and competition, and destabilising aquatic habitats. Freshwater plant pests can cause economic losses through blocking water intakes for hydroelectricity generation, impeded drainage or irrigation. In addition, pests can affect the suitability for recreational activities.
This dataset relates to the "Freshwater pests" measure on the Environmental Indicators, Te taiao Aotearoa website. "

Small amounts of nitrogen are a natural component of healthy rivers. Nitrogen is transferred from land to water and is cycled through different forms, which can have different effects. Moderate concentrations of nitrate can cause weeds and algae to grow too fast. High concentrations of ammoniacal and nitrate nitrogen can be toxic to fish and other aquatic animals.
This dataset relates to the "River water quality trends: nitrogen" measure on the Environmental Indicators, Te taiao Aotearoa website.