99 Luftballoons
By Shane Daly on Friday, June 16th, 2017
Germany. The land of efficiency, beer and lederhosen. For myself however, it was an opportunity to do some cutting-edge research in a country renown for scientific innovation. Some beer was still enjoyed along the way.
The goal of the fieldwork was to successfully measure the aluminium and nickel layers in the upper atmosphere, a region of space between 70 and 120 km in the atmosphere. These metals exist at these altitudes due to the multiple tonnes of extraterrestrial meteoric material, entering Earth’s atmosphere everyday. To do this, a lidar (Light detection and ranging) system was required to measure these species. In short, this system involves firing a high power laser into the atmosphere at a set molecular species and measure the resulting scatter with a telescope. Since one wasn’t available at Leeds, a collaboration was made with the Leibniz Institute of Atmospheric Physics in Germany. As well as this, a novel portable flow-tube was designed in Leeds and brought to Germany to calibrate the lidar laser. It does this by replicating the metal species we want to measure in the flow-tube to check that the lidar is operating at the correct wavelength.
The calibration setup in the lidar bay
Living the lidar life is no simple ordeal. You are at the mercy of mother nature herself. Lidar measurements of metals in the atmosphere are especially sensitive, with one requiring clear night conditions, as any cloud or fog formation can scatter the laser, making it hazardous for any passer-by. There is also too much light interference during the day. Even the moonlight can disrupt measurements, creating too much background noise that can hide the small metal signal you’re looking for. An ideal career for those of a vampirical background.
Overall the trip was a success, proving that one can create a portable flow-tube setup to calibrate a lidar laser, something that has never been done before. For now, this great experience has come to an end and it will be back to the drawing board in Leeds to plan future endeavours.