This week at Macquarie Island: 14 December 2018

Here at Macquarie Island we release two weather balloons every day, 365 days of the year. This is part of the scientific data collection carried out by the Bureau of Meteorology staff.

The weather balloon provides a glimpse of the atmosphere above Macquarie Island. The balloon carries aloft a radiosonde, a box with sensors and an antenna that sends back temperature, humidity, pressure and GPS data every 2 seconds for roughly 2 hours. These data tell us cloud height and thickness, wind speed and direction, and the movement of the air mass.

One day the air might be a freezing southerly travelling up from Antarctica, the next we have a warm north air mass, delivered from Australia. All this information is processed, quality controlled on site, and sent to Australia.

From Melbourne, the data are sent around the world to various Meteorological organizations for input into their super-computers and weather models. Shared through the World Meteorological Organisation (WMO), data are collected from around 1300 upper air (weather balloon) sites world-wide.

Most large Meteorological organisations (like the Bureau of Meteorology) have their own models for their country and geographic area. Forecasters use forecasting models to provide public weather and aviation forecasts, while the climate outlooks are based on climate models. Additional uses for the data include climate change monitoring and research. The Bureau of Meteorology stores the data as a part of the climate record.

Macquarie Island is important, as there are not many other places in the world that collect data at 54⁰ south. We are a tiny island in a big ocean, that is, a location of high quality weather data in an area with minimal observations. We are therefore part of the Global Climate Observing System Upper Air Network (GUAN). This means once a day we attempt to reach a balloon burst height above 5hpa (about 35km). The hydrogen-filled balloons are latex and stretch in the thinning atmosphere as they rise, until eventually they pop.

This summer we are participating in the Year of Polar Prediction — Southern Hemisphere (YOPP-SH) special observing period (SOP) with an additional daily balloon release at Macquarie Island and 1 to 2 extra flights a day from the Bureau of Meteorology’s Antarctic stations. The YOPP is a WMO World Weather Research Program developed in response to the rapid climate changes in polar regions (the Arctic and Antarctic) and related transformation of human activities.

YOPP aims to improve environmental safety by improving environmental prediction capabilities, like weather and sea-ice forecasts, user engagement, and educational activities. The southern hemisphere special observing period runs from the 16th November 2018 to 15th February 2019 and denotes when extra atmospheric, ocean, and sea-ice measurements in addition to the routine observations will be carried out from ships, Antarctic stations, and YOPP-endorsed field campaigns.

For example, around 2000 extra weather balloons will be released (~90 from Macquarie Island). The extra data collected during YOPP-SH SOP will be used for numerical model experimentation and internationally coordinated verification activities, as well as for forecast evaluation and observational impact studies. The extra measurements will help identify ways to improve the prediction systems and develop more accurate and reliable forecasts.

Learn more about the YOPP

The common redpoll Acanthis flammea (current genus/species) found here on Macquarie Island is regarded as a vagrant. The redpoll, a small bird in the finch family common in the northern hemisphere, was first listed in 1758 by the famous Swedish botanist and taxonomist Linnaeus. 

They say the redpoll hitched a ride to the island on a sailing ship like most of us here today. What makes the redpoll so interesting here at Macca is that it is the only place in Australia where you can see them. That makes then a very popular attraction for the tourists that come to the island via the various tourist ships that visit throughout the summer months. 

The redpoll, which is only 10cm and weighs 14 grams wringing wet, is possibly the hardest bird to photograph on the island as they don’t like the wind. They love still mornings or late afternoons where you will find the little suckers playing joyfully in the tussock grass. As you can see in the photos, the Tasmanian Parks and Wildlife Service have kindly installed rails for them to sit on. 

So here on the island when you hear a ‘tweet, tweet, tweet’ and see a little red flash go past, you've just had an encounter with the Macca Redpoll.