Climate constraints on Inverse-derived Regional Net Carbon Ecosystem Exchange over North America
Abstract
We provide a comprehensive analysis of the response of net ecosystem carbon exchanges to climate changes over six North American sub-regions, by investigating the relationships between inversion-induced net ecosystem exchanges (NEE) and climate variables at multi-temporal timescales and global spatial scale. The NEEs are derived from observation-based, multiple time-dependent inversion analyses. The climate variables are global surface air temperature, precipitation rate and precipitation water fields. In the temporal domain, we firstly characterized the relationships between annual NEE and annual mean temperature and precipitation over individual models/regions by performing correlation and regression analysis. We then quantified the NEE-climate relationships by performing lagged and rotation correlation analysis between monthly NEE anomalies and monthly climate variable anomalies. In the spatio-temporal domain, we test our hypothesis that the evolution of the carbon fluxes in space and time is controlled by large-scale El Niño-Southern Oscillation (ENSO) teleconnection patterns by exploring the lagged correlation between the regional carbon flux extremes and large-scale climate anomalies. Our result indicates that in the temporal domain, a strong negative relationship exists between annual NEE and the annual mean precipitation rate over boreal American East and US west. We find a negative correlation between the precipitation and NEE anomalies around June/July over boreal American East, US West, US Midwest (USMW) and US Northeast (USNE). We find a positive lagged (NEE behind T, 3 months) relationship between NEE anomalies centered on August/September and temperature anomalies over the above four regions, as well as a significant negative correlation between spring NEE and temperature anomalies over Boreal American West (NEE behind T, 7 months). In the spatial domain, our analysis confirms the connection between NEE extremes and large-scale temperature and precipitation patterns that are characteristic of ENSO-like anomalies at a lag/lead of zero to a few months over the six regions. Typically, significant consistency occurs over USMW and USNE in both NEE-temperature and NEE-precipitation anomalies despite differences across the inversion models with. Additionally, negative correlation occurs between USMW/USNE NEE extremes and precipitation anomalies in the west and central Pacific. These connections not only reflect a large terrestrial CO2 response to climate changes, but also mirror a mechanistic process of climate variability in the physical state of the atmosphere through mapping a structure of ENSO tropical and extra-tropical teleconnection relationship.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.B23A0377Z
- Keywords:
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- 0430 BIOGEOSCIENCES / Computational methods and data processing