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| Titel |
A spectral analysis of surface CO2 mole fraction data |
| VerfasserIn |
James Barlow, Paul Palmer |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250076877
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| Zusammenfassung |
| A current challenge in studies of the global carbon cycle is to quantify the response of natural
emissions and uptake of CO2 to rapidly changing climate. We use wavelet analysis to
interpret observed temporal variations in ground-based CO2 mole fraction data across the
world over the past 3-4 decades. Most importantly, the wavelet analysis allows us to
decompose a timeseries as a function of frequency and time. We examine temporal and
spatial variations in the atmospheric growth rate of CO2 and quantify long term trends in the
amplitude of the seasonal oscillations of CO2 concentration values. We define a
metric to estimate changes in the length of the CO2 uptake period in the Northern
Hemisphere, allowing us to quantify changes to the start and end dates of this period
and consider how the long term trends vary zonally. We present the results of the
seasonal cycle trend analysis which exhibit increasing amplitudes in the Northern
Hemisphere, with the exception of the mid-latitudes, and where the magnitude of the
increase is typically greater towards the higher latitudes. There is little change in
amplitude in the Southern Hemisphere. We also find that the start/end dates of the
uptake period are becoming earlier at nearly all latitudes. The advance in Spring and
Autumn phases typically results in a small net change to the overall length of the
carbon uptake period. Finally we present the performance of a multi-parameter linear
regression model, driven by gridded model analyses of temperature, short-wave infrared
radiation, and precipitation, to reproduce observed CO2 variations across the globe. |
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