Coastal sea-surface temperature

  • Image, Coastal sea-surface temperature.

    Coastal sea-surface temperature is influenced by solar heating and cooling, latitude, and local geography. It is hard for some marine species to survive when the sea temperature changes. This can affect marine ecosystems and processes. It can also affect fish-farming industries based in our coastal areas.

    We classified Coastal sea-surface temperature as a case study.

    Key findings

    Globally, climate change is expected to increase coastal sea-surface temperatures. In New Zealand, summer-to-winter variation is influenced more by local geography (eg how exposed a beach is to the open sea and sunshine hours) than by the large-scale circulation of oceans.

    • Annual mean coastal sea-surface temperature ranges typically display year-to-year differences of plus or minus 1–2 degrees Celsius.
    • The annual mean coastal sea-surface temperature decreases gradually from north to south.
      • Sites in northern New Zealand have an annual mean coastal sea-surface temperature around 17 degrees Celsius.

      • Sites in southern New Zealand have an annual mean coastal sea-surface temperature around 12 degrees Celsius.

    Figure 1

    Note: Locations are ordered geographically from north to south. Data spans 1953–2012; time series vary between locations.

    Figure 2

    Note: Leigh is the Leigh Marine Station in the north-west of the Auckland region. Portobello is the Portobello Marine Station east of Dunedin along the Otago Peninsula. The circles indicate annual mean temperatures for years with more than 345 days of data. These sites are presented because they have the longest time series.

    Definition and methodology

    The coastal sea-surface temperature variations in this case study use data from 11 monitoring locations: Ahipara Bay, Leigh Marine Station, Tauranga, Napier, New Plymouth, Wellington (Evans Bay and Lyall Bay), Lyttelton, Jackson Bay, Portobello Marine Station, and Bluff. It also has time series for the stations with the best available data: Leigh Marine Station near Auckland, and Portobello Marine Station near Dunedin.

    Handheld mercury thermometers were used for early measures of coastal sea-surface temperature. In the early 1980s, they were replaced by digital thermometers. Since 1990, electronic sensors with internally recording data loggers have been used.

    Large gaps in the records prevent comparisons between monitoring stations. Annual mean temperatures are only reported for years with more than 345 days of data.

    Data quality

     Topic Classification   Relevance Accuracy 
    Sea level, temperature, and circulation Case study

    relevance-direct 
    Direct

    accuracy-medium 
    Medium

    See Data quality information for more detail.

    Archived pages

    See Coastal sea-surface temperature (archived October 2016).

    Updated 27 October 2016

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