Greenhouse gas study at Imperial


I’m doctor Heather Graven I’m a lecturer
in the physics department here at Imperial College London and I’m leading a research group studying greenhouse gases in the atmosphere. so we’re here on the roof of the Huxley building at Imperial College London about 24 metres up and we’re measuring greenhouse gases carbon dioxide and methane. We’re also measuring wind speed and wind direction to try to understand what’s driving the variations in the greenhouse gases that we observe. This is our weather station it includes
wind direction and wind speed sensor a sensor to measure the temperature and an
inlet that is connected to the instrumentation in our laboratory which
allows the air to be measured. So the latest estimate we have is that the UK
emits approximately 500 million tons of greenhouse gas every year and that
figure has been steadily decreasing ever since the early 1990’s. Mainly due to a
decrease in coal consumption in power stations but recent efforts in reducing
greenhouse gas emissions such as the climate change act in 2008 and I’m sure
a lot of you’ve seen the low emission zones in London are aimed at reducing
this even further. In our laboratory methane and carbon dioxide
concentrations are measured by a cavity ring down spectrometer and in this plot
you can see our first measurements. Concentrations during the night go up
and during the day when the wind speed increases they go down. So using a
sophisticated atmospheric model the history of the air arriving at our
observation site can be traced and this allows researchers to estimate what
regions have emitted the greenhouse gas being observed at our Imperial College
London sites and the model works by releasing particles from our observation
site and seeing where they go back in time. Here our model particles are
represented by bubbles and seeing where those bubbles end up gives us an
indication of where the air and hence the greenhouse gases have
originated from. So this shows the air history for a given day at our
observation site here at Imperial College London. So coupling observations
of greenhouse gases with our atmospheric transport models can allow us to
independently verify national emission levels. This gives the UK government
confidence in its mission reports.

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