Glaciers ‘sad and dirty’ ahead of annual survey
New Zealand’s glaciers are expected to look ‘‘pretty pathetic’’ following our hottest summer on record, Niwa says.
Niwa scientists are taking to the skies today as part of an annual survey of 50 South Island glaciers, but preliminary photos already show them looking ‘‘sad and dirty’’.
The survey compares the end of summer snowline which reveals how much of the previous winter’s snow remains to contribute to long-term glacial ice accumulation.
‘‘At this time of year we can see the effects of the summer melt but following such an extreme summer the layers really start to peel back and you can see how harsh the effect has been on the glaciers,’’ Niwa climate scientist Andrew Lorrey said.
‘‘Where it becomes a concern is if there is a succession of seasons like this within a decade or two – that’s when it can cause the overall volume of the glacier to decline.’’
The survey is undertaken every March at the end of summer, and this year Stuff national correspondent Charlie Mitchell will accompany five scientists on board the snowline flight.
The Niwa team – Lorrey, Trevor Chinn, Dr Huw Horgan, Dr Brian Anderson and PhD student Lauren Vargo from Victoria University – use specialised cameras from a light aircraft which takes thousands of photos from different angles.
The photos will then be used to build 3D models of glaciers that can be compared year on year to give an accurate depiction of the volume of ice that has changed.
Glacier fluctuations are among the clearest signals of climate change, because they are highly sensitive indicators of atmospheric temperature and precipitation levels.
It will be the 40th year the survey is conducted and Lorrey, who leads the project, said the information gathered over the past four decades has produced a unique and incredibly valuable dataset that provides an independent measure of how climate change and variability are affecting our water resources.
Victoria University glaciologist Professor Andrew Mackintosh is also expecting one of the largest melt years ever recorded.
‘‘The marine heatwave this summer, where temperatures have been up to 6C higher in some parts of the Tasman Sea, means we are expecting to see a much higher snow line.’’
For the first time this year a thermal imaging camera will be used that Lorrey hopes will reveal more about the debriscovered ice.
‘‘While it is experimental, we hope it may tell us something about the thickness and extent of the debris cover and the properties of the ice underneath it.’’