Wave lengths and CO2

Guest

Are your measurements of wavelengths and CO2 flux related, and how?

Joined: 23 Mar 2004 Posts: 74 Location: Barrow, AK

Well, Ian, that is a good question. Let me see if I can work it out:

The reflectance that we measure tells us what wavelengths of light are being reflected by the ground, which, I know this seems obvious, but to be thorough, tells us which wavelengths of light are being absorbed by the ground. This is important because chlorophyll in plants absorbs mostly blue and red light. It reflects the green light and thus plants LOOK green to us. Other parts of vegetation such as the stems and stalks, etc. reflect light that is longer in wavelength, like almost infrared, thus it is called near-infrared light. When we take the reflectance, we measure wavelengths from below blue through the infrared range. The NDVI calculation that we do takes all of those wavelength measurements and converts them into a number that we can then compare directly to other reflectance measurements that have been taken in other areas. So reflectance measurements kind of boil down to a measure of plant production.
So how does this relate to CO2? Well, plants and the photosynthesis that they do is an integral part of the carbon cycle. So, hopefully, when we determine the amount of carbon flux in an area and we have the NDVI, eventually scientists will be able to connect these to pieces of information numerically and use the NDVI to predicts the carbon flux of an area.
I hope that answers your question! Let me know if you have any more.
Mrs. N-O