Mauna Loa and South Pole Isotopic C13 Ratio (y-axis inverted) Graphic | Scripps CO2 Program

Mauna Loa and South Pole Isotopic 13C Ratio (y-axis inverted)


Description

The scale of δ13C is inverted so that seasonal patterns of CO2 concentration δ13C appear with the same phasing.

Black Dots: Monthly average reduced isotopic ratio of atmospheric carbon dioxide, δ13C, versus time at Mauna Loa Observatory, Hawaii (20°N, 156°W) where δ13C is in per mil.

Black Curve: The sum of 4 seasonal harmonics and a spline function to the Mauna Loa δ13C data. The seasonal harmonics include a linear gain factor, to represent increasing amplitude with time.

Red Dots: Monthly average atmospheric carbon dioxide reduced isotopic ratio, δ13C, versus time at South Pole, Antarctica where δ13C is in per mil.

Red Curve: The sum of 4 seasonal harmonics and a spline function to the South Pole δ13C data. The seasonal harmonics include a linear gain factor, to represent increasing amplitude with time.

Data from Scripps CO2 Program.