Inconsistency between bottom-up and top-down global gross primary production and soil respiration
Abstract
The terrestrial carbon cycle strongly influences global climate change. Both top-down (e.g., remote sensing and earth system models) and bottom-up (derived from field measurements) estimates have been made of major components (e.g., gross primary production, GPP, and soil respiration, RS) of the terrestrial carbon cycle, as well as their response to global climate change. However, these top-down and bottom-up estimates have not been compared for consistency.
In this study, we first partitioned top-down GPP estimates into their NPP and autotrophic respiration components, and calculated global RS (76±21 Pg C yr-1, 95% confidence interval). There is only a ~28% probability that these estimates are consistent with the bottom-up global RS estimates (86±6 Pg C yr-1). Second, based on the bottom-up global RS estimates, we then partitioned RS into its different components (shoot and root respiration), and calculated the resulting implied global GPP (140±46 Pg C yr-1), which had ~29% probability of being consistent with the top-down global GPP estimates (120±13 Pg C yr-1). This highlights the inconsistence between bottom-up and top-down based GPP and RS estimates that have a ~20 Pg C gap between them. The reasons of the inconsistency need further study for better understanding global terrestrial carbon cycling in the future.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMEP23D2283J
- Keywords:
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- 1615 Biogeochemical cycles;
- processes;
- and modeling;
- GLOBAL CHANGE;
- 1819 Geographic Information Systems (GIS);
- HYDROLOGY;
- 1914 Data mining;
- INFORMATICS;
- 1942 Machine learning;
- INFORMATICS