You wouldn't imagine that any of the great revolutions in science came about whilst sitting in a van at Corley service station, and this visit proved no exception. It will probably not feature in any GAUGE campaign highlights package. Nevertheless, as we drove on towards Cranfield I could sense the initial sparks of enthusiasm for this summer's approaching campaign flicker ever closer to striking. We were heading for the Facility for Airborne Atmospheric Measurements, known to most as FAAM, bringing instrumentation in the form of Manchester University's QCLAS (Quantum Cascade Laser Absorption Spectrometer) and CIMS (Chemical Ionisation Mass Spectrometer), ahead of the GAUGE re-fit of the large Atmospheric Research Aircraft.


An early morning start - the research aircraft sitting on the apron at Cranfield airport.

Between them, these two instruments cover a wide range of species, both directly and indirectly relevant to climate change and air quality. The QCLAS measures methane (CH4) and nitrous oxide (N2O), which along with carbon dioxide (CO2) form the three most important greenhouse gases in terms of human influence on the Earth's climate. The CIMS is capable of detecting many species, including nitric acid, formic acid, acetic acid, hydrogen cyanide, nitryl chloride and bromine oxide to name only a few. The great opportunity provided by installing these instruments on the FAAM research aircraft is that, by combining their measurements with the vast amount of other gas phase, aerosol, cloud and thermodynamic data collected on board, we can build up a much clearer picture of the state of the atmosphere across the UK within a short space of time.


Flying at 50 ft above the North Sea on a calm day in May

This is to be our second year of GAUGE flying, after we successfully racked up around 60 flying hours last summer. Flying on the research aircraft is certainly a unique experience; it is the only time you are ever likely to travel in a four-engined jet aircraft (a BAe-146) at altitudes as low as 50 ft over the sea! The constraints on operating instrumentation on board an aircraft also bring their own challenges. Good preparation is vital; an issue that is not picked up until you are in the air could easily result in loss of data for the entire flight. From the moment science-power is turned on four hours before take-off you are up against the clock to get everything ready. Often this means starting as early as 4 a.m., but I usually find any tiredness doesn't set in until the evening when the flight is completed and you're back on the ground. There's always a buzz about the place as everyone gears up towards take-off, and it's a relief to finally be in the air with everything (hopefully) in full working order.

Arriving at FAAM once again this year, it was great to be greeted by familiar faces, and have a chance to catch up on the intervening months. Having unloaded the instruments from the van, they were wheeled into the lab for the extensive ground testing necessary before the flying campaign recommences. Whilst all this may not be the most glamorous of science, and despite the numerous frustrations we will likely encounter over the coming weeks as we grapple with elusive instrumental issues, come the start of May when we are taxiing for the first GAUGE flight of the summer, I know it will all seem worthwhile.