ALT and PTB Stations Isotopic C13 Trends Graphic | Scripps CO2 Program

ALT and PTB Stations Isotopic 13C Trends


Black Dots: Monthly average atmospheric Isotopic C13 concentration versus time at stations in the Northern and Southern Hemispheres where 13C concentration is in parts per million in the mole fraction (p.p.m.).

Black Curves: The sum of 4 seasonal harmonics and a spline function to the stations 13C concentration data. The seasonal harmonics include a linear gain factor, to represent increasing amplitude with time.

Station code names are as follows: ALT = Alert, NWT, Canada, and PTB = Point Barrow.

Data from Scripps CO2 Program.

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