UK climate instruments take a ride on NASA's Global Hawk
6 March 2015
Two cutting-edge science instruments developed by UK researchers took to the skies aboard NASA's Global Hawk research aircraft for the first time yesterday.
NASA's Global Hawk. Photo: James Ross, NASA.
The two instruments are the first from the UK to take advantage of the Global Hawk's capabilities. They were developed as part of a four-year collaboration between the NERC's Coordinated Airborne Studies in the Tropics (CAST) project and NASA's Airborne Tropical Tropopause Experiment (ATTREX).
The uninhabited aircraft, based at NASA's Armstrong Flight Research Centre, California, can fly at twice the height of Mount Everest and double the altitude of a commercial jet for more than a day at a time, travelling the equivalent of half of Earth's circumference in a single flight in an atmosphere where the air pressure is less than a tenth of that at sea level.
The aircraft is flying above the equatorial regions of the Pacific Ocean at an altitude of 20km, where the lowest layer of the atmosphere, the troposphere, meets the stratosphere above. Scientists believe this area, known as the tropopause, plays a critical role in Earth's climate.
The first of the instruments, GHOST (Greenhouse Observations of the Stratosphere and Troposphere), was developed by the Science & Technology Facilities Council's (STFC) UK Astronomy Technology Centre (UKATC) in Edinburgh, in a joint effort with the universities of Edinburgh and Leicester.
Sitting in the belly of the Global Hawk, GHOST behaves like a sub-orbital satellite instrument, measuring greenhouse gases such as carbon dioxide and methane across large regions but in fine detail. This will allow scientists to produce precise maps of where greenhouse gases are being released and taken up at the Earth's surface - vital information for international climate negotiations.
The second instrument, AIITS (the Aerosol Ice Interface Transition Spectrometer), measures particles like dust, water droplets and ice crystals. The transport of particles and pollutants between the troposphere and stratosphere plays a crucial role in the climate system and the health of the ozone layer. AIITS was jointly developed by the universities of Hertfordshire and Manchester.
The two UK pieces of kit were joined onboard by instruments from the ATTREX project. These will focus on the transport of water vapour and other trace gases into the stratosphere. Studies show that even slight changes in the amount of water vapour in the stratosphere can warm temperatures by absorbing heat rising from the surface.
Dr Neil Harris at the University of Cambridge, science lead for the NERC CAST project, said:
These are important issues for climate science. The chance to fly two new UK instruments on the Global Hawk is very exciting. We are flying at temperatures below -80C in the equatorial East Pacific to investigate how thin cirrus clouds form. We then track back below the new NASA OCO-2 satellite to provide more detailed measurements where the satellite measures.
Andy Vick, innovations manager at STFC's UKATC facility and the lead investigator for the GHOST project, celebrated the successful first flight of GHOST:
These incredibly sensitive instruments, that were originally developed to meet major astronomical challenges by dealing with very low levels of light, are now being used to instead accurately measure the incredibly tiny fluctuations in the levels of greenhouse gases. This new information will allow us to better understand these changes and the data collected will be used to evaluate and improve global models used to predict future climate change.
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