Source: NIWA – National Institute of Water and Atmospheric Research
Every day at 8am Hawke’s Bay farmer Robert Buchanan heads out to his rain gauge to measure the rainfall.
It’s a job he inherited from his father but insists it’s no chore. “It’s like putting my boots on,” he says. “You hardly realise you’re doing it.”
Robert’s father started the rainfall measurements 50 years ago and kept doing it for the next 25 years until Robert took over. “We’re still using the original measuring instrument – it’s glass and no one’s dropped it so far.” And when Robert’s away his son steps in to ensure there are no gaps in the record.
The Buchanans are part of a vital network of about 250 rainfall and climate station volunteers across New Zealand who send their weather measurements to NIWA every month where they are used by scientists researching New Zealand’s climate.
The third generation Ongaonga farmer sees it as “my little contribution to the weather people” but wonders in today’s hi-tech world whether measuring rainfall the old-fashioned way is of much use anymore.
That’s not a view NIWA principal climate technician Andrew Harper subscribes to.
“Essentially the beauty of the network is in the consistency of the method of measuring the rainfall and the quality of the data collected. We’ve basically used the same raingauge design since the network started in the late 1800s.”
Measurements like these with consistent gauge design and measurement technique that have been made regularly at the same place over a long period of time are a scientist’s bread and butter because they can be trusted to tell an accurate picture which is important in developing reliable climatological records. All the data contributes to many climate applications and services such as NIWA’s soil moisture deficit maps, its virtual climate stations network, drought monitor and climate maps among other research.
Andrew says knowing the climate that has taken place in the past is crucial to understanding climate change and any mitigation that might be required. “We are also able to build with confidence the monthly statistics and the 30-year normals which are important in detecting any changes in climate patterns over time.”
Automated weather stations may provide up-to-date and real time data straight to a mobile phone but Andrew says while they have many uses, they present challenges for comparing long-term datasets.
In its heyday in the 1980s the volunteer observer network numbered more than 1500 people but over time has dropped for many reasons and largely reflects changing needs.
“It’s a big commitment and not too many of us would want to do that so it’s a special effort they’re putting in. It is very much valued at NIWA.”
NIWA climate technician Seema Singh is in charge of collecting the data from the observers and helping them out with any problems. It’s a job she has been doing for seven years and one she says is incredibly rewarding.
“I find it very special working with them. A lot are elderly, retired or have been doing it a long time and they are all really kind.”
Seema says she has enjoyed building a relationship with all the observers and admires their dedication.
“It is much bigger than just collecting numbers, people are very passionate about it.”
Seema is also the keeper of all historic climate observations, many made in pencil on paper that has faded and become more delicate over time. “Some are very descriptive, especially when it comes to snow levels and describing extreme weather events at their farms.”
Sitting on shelves in NIWA’s Wellington office are two folders full of the Buchanans’ Ongaonga station rainfall records that provide an insight to farming in Central Hawke’s Bay over five decades. In April 1969 for instance Robert’s father wrote: “Late autumn rain. Country now green but feed very short. Prospects for winter are grim but we could get a warm May.”
And in 1976: “A cool, wet month with high winds. An unusual amount of grass growth.”
These precious historic documents and many more like it are currently being scanned and photographed while the original documents will be sent to a temperature-controlled storage facility.
Sorting through them has been a time-consuming job for Seema but she says she’s been finding things she’s never seen before.
“This is something New Zealanders can boast about. There is so much important information here – it is an important legacy and makes a huge contribution to our climate science.”