CarbonTracker is a system that calculates carbon dioxide uptake and release at the Earth's surface over time. It estimates the carbon dioxide exchange from an 'atmospheric point of view'. Since CO2 mole fractions in the atmosphere reflect the sum of all the CO2 exchange at the surface, they form the ultimate record of the combined human and natural influence on greenhouse gas levels.
A simple analogy for this approach is your monthly check-book: by looking at your bank statement you know exactly how much money you have in your account on the 1st day of a new month. The challenge is to reconstruct the sum of income and expenses since the last month that matches your total exactly. For the global atmospheric carbon dioxide budget, this check book looks something like the figure on the left.
By measuring carbon dioxide frequently (the bold-faced sum that makes the total), and at many places on Earth, CarbonTracker can break down the budget even further, and thus keep track of uptake and release for many places on Earth. And just like your bank statement, the atmosphere never lies!
How does CarbonTracker work?
CarbonTracker produces
model predictions of atmospheric
CO2 mole
fractions, to be compared with the observed atmospheric
CO2 mole fractions. The difference
between them is attributed to differences in the sources and
sinks used to make the prediction (the so-called 'first-guess')
and the sources and sinks affecting the true atmospheric
CO2. Using numerical techniques, these
differences are used to solve for a set of sources and sinks
that most closely matches the observed
CO2 in the atmosphere. CarbonTracker
has a representation of atmospheric transport based on weather
forecasts, and modules representing air-sea exchange of
CO2, photosynthesis and respiration by
the terrestrial biosphere, and release of
CO2 to the atmosphere by fires and
combustion of fossil fuels. More details about these different
components and why they are needed can be found in
our documentation pages.
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Find out more about...
Greenhouse Gases
Carbon Dioxide
The Carbon Cycle
Climate Change