More Fun with Graphs

Recently, a group of us within my research network undertook a really interesting workshop. This has lead to some improvements to our processing, forcing me to return to the raw data and re-analyse it. As you would expect, the resulting data is only slightly different to previous analyses, but we have greater confident in our process.

Anyway, it led me to explore the full dataset that I have for my site (just shy of two years worth now) and to produce a few interesting graphs.

This one shows the average diurnal CO2 concentration at the site. I like it because you can see that the CO2 we spend a lot of time talking about in the blogosphere fluctuates even daily – over the study period of my site and it’s location, by more than 17ppm on average.

With everything breathing away at night, the average reaches 395ppm before the plants sing, “Here comes the sun”, kicking photosynthesis into gear (well, not exactly, but it would be cool), which brings the CO2 concentration down again. Which is exactly what overlaying the carbon flux (red) shows in the following graph.

By about 11am, photosynthesis peaks to avoid too much water loss as the day warms up, changing the slope of the CO2 concentration graph as well. By 4pm, photosynthesis is taking in less CO2 than is being lost through respiration and the concentration slides back up.

Looking at the same data, instead by breaking it up in monthly 30min averages you can see the peak activity as well as the CO2 concentration level over the year.

Into our summer, the plants do their bit to keep the CO2 concentration in check – and this is an arid site. Personally, I see this as geo-engineering at its finest. I’m not holding out for technology to do the work of undoing our contribution to the greenhouse gas concentrations. We’ve already got a great option for drawing CO2 back out of the atmosphere; plant trees!

Of course, it then matters what you do with that stored carbon!


2 thoughts on “More Fun with Graphs

  1. Hi Tim great to see someone doing real science . 17ppm in a arid site wow imagine a rainforest , thanks very interesting .


  2. Cheers David. We see as much as 4g of carbon per metre squared per day. Obviously, as you suggest, a rainforest can be far more productive. However, when it’s an old growth forest, most of literature (and common-sense) suggest it becomes almost carbon neutral. It makes sense to employ fast growing species to suck up carbon from the air, but it won’t be enough to simply grow forests because this carbon will be lost with combustion (either bushfires or decomposition). On the other hand, but removing and using the locked carbon in the form of wood also means you remove nutrients from the environment… lol

    While it’s complicated, photosynthesis is, in my opinion, the best way to tackle rising CO2 concentration (alongside, of course, decarbonising our energy). 🙂


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