Cape Town - In a first for the country, scientists from the South African Weather Service (SAWS) and the German Research Centre Juelich are working together near Beaufort West in the Western Cape to launch high-altitude balloons to measure the chemistry of the atmosphere, including pollutants.
These balloons can carry small measuring instruments up to an altitude of approximately 35km, well above the range of aircraft, to investigate the atmosphere from the ground up to those otherwise inaccessible altitudes.
“The challenges of such balloon launches are multifold,” SAWS said on Thursday. “Just imagine filling a latex balloon with enough helium to lift a 4kg instrument with a GPS tracker. This balloon ascends to an altitude of 35km, while recording temperature, pressure, water content, methane, carbon dioxide, ozone etc. during the flight.
“After bursting we predict where the parachute will drift to – finding out on which farmer’s land it has landed and trying to locate it on the farm. Very much a needle-and-haystack scenario,” SAWS said.
Other challenges experienced include sudden wind gusts breaking a balloon before it could even take off, and recovering the sensors after a particularly hard landing, all of which are time-critical, during a thunderstorm.
“Despite this, the first four launches have already provided valuable and precise information on the vertical distribution of the concentrations of water vapour, ozone, carbon dioxide, carbon monoxide, methane and many other trace gases.”
SAWS said the purpose of the project is to collect data about important pollutants and greenhouse gases in the atmosphere, which are extremely scarce in the southern hemisphere, especially at higher altitudes.
“Normally, one has to rely on remote sensing instruments such as satellites, but even this sophisticated equipment requires independent verification, which is one of this project’s objectives. The gases in question are of importance as they can absorb sun energy at these high altitudes, which influences surface weather,” SAWS said.
Cape Times