A jet departs from Cairns, far north Queensland. Its destination? The atmosphere's "washing machine".
A team of German researchers on board the modified aircraft, which acts as a flying laboratory, hope to better understand what is going on in the atmosphere above the clouds.
The jet has been fitted out with custom-built, highly sensitive scientific instruments, normally only found in a laboratory.
Max Planck Institute for Chemistry researcher Clara Nussbaumer said the team was often measuring trace gases in the atmosphere at levels as low as one part per trillion.
"Imagine this as around one drop in 20 Olympic-sized swimming pools," she said.
"And we have to do this extremely fast because we're flying in an aircraft at around 250 metres per second."
The flight is their third over the tropics, with researchers already tracking the weather and taking atmospheric measurements above the Amazon and Africa.
Max Planck Institute for Chemistry professor Horst Fischer said a chemical called OH radical, which is found in the atmosphere above the tropics, acts as a kind of "detergent" transforming emissions into something more soluble before they are transported back to earth by rain.
"The tropics are the 'washing machine' of the atmosphere and so we are particularly interested in the tropics," he said.
High temperatures in the Pacific Ocean off Australia's northeast coast create columns of upward rising warm air, considered the strongest in the world.
These columns, called high reaching convection, allow heat, moisture and gasses to be transported from the surface of the planet into the atmosphere.
"It's an exciting place to explore as an atmospheric scientist," Dr Nussbaumer said.
The team of four scientists can spend up to nine hours on each flight, tracking expected - and unexpected - weather events.
Joachim Curtius, a professor at the Goethe University Frankfurt's Institute for Atmosphere and Environment, said researchers designed their flight path to coincide with predicted weather events.
"It's great when we find things where we expect them - it means our models are reliable,"he said.
"But it's probably more exciting to find things we don't quite expect as it gives us the chance to further improve the forecasts and predictions under our changing climate."
Mr Curtius said the measurements taken in the team's 150 flying hours would help improve modelling of chemical processes in the atmosphere.
"This will help us even more accurately predict future climate developments," he said.
