Spectral indications of unexpected contributors to atmospheric CO2 variability?
✍ Scribed by Hughes, Gary B.; Giegengack, Robert; Kritikos, Haralambos N.
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 127 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0899-8418
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✦ Synopsis
The frequency spectrum of Northern Hemisphere atmospheric CO 2 concentration shows strong periodicities at 6.2, 1.0 and 0.5 years. The 6.2 year cyclicity has been attributed to non-linear interactions between the annual cycle and the atmospheric pole tide. The yearly signal is linked to terrestrial photosynthesis; phase analysis shows that annual CO 2 minima occur at a lag of approximately 85 days from insolation maxima. Variations in the nominal yearly period occur during times of anomalous anthropogenic CO 2 production. Periodicity at 6 months represents a deviation of the yearly signal from an annual sinusoid. If the yearly signal is largely sinusoidal, a plausible source of the 6 month periodicity could be cyclic phytoplankton productivity driven by natural insolation modes. Together, the three largest spectral peaks account for over 99% of the variation in detrended CO 2 data.