-based weather observations

Requirement What to do if you find a filled or partially inflated ? Balloon-based weather observations provide precise measurements of , , Call 000 and ask for Fire Brigade assistance , speed and direction, and can reach an between 16km – 35km in the upper • The Bureau uses hydrogen gas to fill its atmosphere. These observations provide vital weather . Hydrogen can be explosive information which enhances our understanding of when exposed to an ignition source such as a the climate, and is used by the Bureau of flame, electromagnetic signal or even low level in forecasts and warnings to protect static electricity. life and property in Australia. • If you find a weather balloon that is still inflated, even partially, that means hydrogen is present The Bureau also has international obligations under in the balloon and it is HIGHLY FLAMMABLE. the Convention of the World Meteorological Organization (WMO) to provide weather and • Keep at least 10m away and do not approach climate-related measurements of the upper the balloon. atmosphere. • Call Emergency Services (000) immediately and ask for Fire Brigade assistance. Worldwide, weather balloons are released from approximately 1300 locations each day. The Bureau releases about 56 per day, or about 20,000 Balloons that have burst do not pose an per year, from 38 locations within Australia and its immediate risk and can be handled. They may offshore territories including Antarctica. appear very torn and shredded.

Other items that may be attached to a balloon that do not pose a risk includes: • A foil-coated cardboard target shaped like a 4- sided pyramid (picture 1). This is used to slow descent of the balloon and/or track the balloon via . • A small white plastic box known as a . This has the sensors used to measure meteorological variables • A parachute, used to slow descent when a target is not used; • A torch, used for some night balloon releases.

All of these items can be disposed of with normal household garbage and recycling. Do not burn or incinerate the radiosonde.

Photo 2 – Radiosonde, with Bureau label including Photo 1 – Weather balloon and attachments, released how to dispose of radiosonde. by weather observer Photo credit: Bureau of Meteorology, 2009

Additional information Minimising our environmental impact

Released from the ground, are devices The Bureau seeks to minimise its footprint on the that are used to measure meteorological elements. environment wherever possible, and has A weather balloon filled with hydrogen gas carries undertaken a number of measures to reduce the the radiosonde into the upper atmosphere, along environmental impact of weather balloon flights by: with additional items including a cardboard target • pursuing alternate upper atmosphere technologies; (as seen in picture 1), and potentially a parachute • using more environmentally-friendly materials; and and a torch. • Working with suppliers to make continual Depending on the size of the balloon, the improvements. expansion that takes place as it rises into lower pressure causes the balloon to burst and the Although complementary technologies such as instrument will descend back to Earth. During the satellites and wind profilers are increasingly used by radiosonde’s flight, it constantly transmits the Bureau, weather balloons remain a critical atmospheric temperature, humidity and pressure component of the observation network and will data to receiving ground equipment. This continue to play an important role during the next equipment processes and converts the data into decade and beyond. meteorological weather messages, and is also displayed as aerological diagram used by forecasters to assist in forecast and warning How to inform the Bureau if you find a services. More information can be located here. balloon.

The Bureau is interested to know if you find a balloon. Of specific interest is the 10 digit alphanumeric serial number on the radiosonde located on the lower right hand corner. From this number, the Bureau can determine when the balloon was released and from what location. The radiosonde is a single use instrument and may be safely disposed with household waste.

To assist with reporting a balloon finding, go to the Bureau's feedback page, and search for 'I found a weather balloon'. This will open a feedback form which you can complete and submit your findings to the Bureau.

Submit feedback here

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Photo 3 – Aerological diagram