NIWA's National Snow & Ice Monitoring Network

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NIWA is setting up a national monitoring network to measure snow and ice in New Zealand.

The network will probably have 10–12 sites. The first three sites are now operating, at Mt Cook village, at Arthur’s Pass, and at the Chateau at Ruapehu.

WHY: Climate change could bring big changes to snow & ice. This will affect hydro-power, agriculture/irrigation, and tourism/skiing industries.

With increased rainfall and warmer temperatures, we might expect:

  • less snow at low elevations and more rain;
  • more snow at higher elevations and/or close to the main divide;
  • more river flow and less low elevation snow cover in winter;
  • less river flow in spring.

These projected changes in the amount and seasonal pattern of river flows have not been quantified, and remain research questions. Such changes would be advantageous for electricity generation (assuming current demand patterns are unchanged), but undesirable for irrigators and tourism/skifield operators.

WHY: We need better information

Snow as a resource is poorly quantified in New Zealand. We don’t really know how much snow we’ve got.

For glaciers, NIWA has done aerial surveys of the end-of-summer snowline at 50 Southern Alps glaciers since 1977. But there is no national on-the-ground monitoring of glacier thickness and extent.

HOW: Special climate stations plus advanced modelling

The Snow & Ice Network climate stations (which measure air temperature, wind speed and direction, relative humidity, air pressure, solar radiation, and precipitation) will have an extra sensor to measure snow depth. The sensor is an ultrasonic ranger, which measures the distance between itself and the ground. As snow falls and accumulates, this distance decreases and we can measure the total amount of snow at that location.

This, combined with advanced model capabilities, will allow NIWA to understand more accurately seasonal snow in NZ and assist with calculating glacier mass balance throughout the Southern Alps. Network maintenance will be scheduled to coincide with glacier field measurements (where possible) to assist university researchers.

WHERE: 10–12 key sites

At this stage 10-12 sites have been proposed, but this could change depending on demand, coverage, and collaboration opportunities.

The sites are mainly in the South Island and have been selected to achieve maximum coverage across NZ alpine areas and where possible compliment other research (e.g., Brewster Glacier site will assist university researchers).

We have completed installation of snow monitoring equipment on existing climate stations at:

  • Mt Cook village
  • Arthur’s Pass
  • Chateau at Ruapehu

These lower elevation sites are crucial to better understanding low elevation snow storm events (e.g., the storm which blanketed parts of Otago and Canterbury on 12 June 2006) and understanding the relationship between elevation and snow depth.We also now have a station at Albert Burn in association with Otago Regional Council.

High elevation sites on DoC land are currently in the early phases of a multi- conservancy concession application. We hope the following stations will be established in the summer of 2008/2009:

  • Brewster Glacier (above Haast Pass Road)
  • Nelson Lakes Region
  • Mueller (near Mueller Hut, Mt Cook)
  • Rolleston Glacier (Arthur’s Pass)
  • Murchison Mountains (Fiordland)

Further out, we are considering:

  • Ivory Glacier (West Coast)
  • Ramsay Glacier or surrounds (head of the Rakaia River)

Latest Developments

This map shows the established and proposed NIWA snow & ice monitoring sites. Also shown are the three existing high elevation sites owned by Meridian Energy Ltd., and a site proposed in collaboration with Otago Regional Council.