# Global and Brazilian carbon response to El Ni\~{n}o Modoki 2011-2010

## TL;DR

This study uses satellite data and carbon cycle models to quantify the global and Brazilian carbon flux responses to the 2010 El Niño Modoki, revealing complex regional contributions and near-zero net ecosystem change in Brazil.

## Contribution

It introduces a satellite-based, 4D-variational assimilation approach to quantify spatially resolved carbon fluxes during climate events, specifically applied to the 2010 El Niño Modoki.

## Key findings

- Global net carbon flux tendency was -1.60 PgC (2011-2010).
- Brazil's net flux tendency was -0.24 ± 0.11 PgC.
- Brazil's biomass burning tendency was -0.24 ± 0.036 PgC.

## Abstract

The El Ni\~{n}o Modoki in 2010 lead to historic droughts in Brazil. We quantify the global and Brazilian carbon response to this event using the NASA Carbon Monitoring System Flux (CMS-Flux) framework. Satellite observations of CO$_2$, CO, and solar induced fluorescence (SIF) are ingested into a 4D-variational assimilation system driven by carbon cycle models to infer spatially resolved carbon fluxes including net ecosystem exchange, biomass burning, and gross primary productivity (GPP). The global net carbon flux tendency, which is the flux difference 2011-2010 and is positive for net fluxes into the atmosphere, was estimated to be -1.60 PgC between 2011-2010 while the Brazilian tendency was -0.24 $\pm$ 0.11 PgC. This estimate is broadly within the uncertainty of previous aircraft based estimates restricted to the Amazonian basin. The biomass burning tendency in Brazil was -0.24 $\pm$ 0.036 PgC, which implies a near-zero change of the net ecosystem production (NEP). The near-zero change of the NEP is the result of quantitatively comparable increase in GPP (0.34 $\pm$ 0.20) and respiration in Brazil. Comparisons of the component fluxes in Brazil to the global fluxes show a complex balance between regional contributions to individual carbon fluxes such as biomass burning, and their net contribution to the global carbon balance, i.e., the Brazilian biomass burning tendency is a significant contributor to the global biomass burning tendency but the Brazilian net flux tendency is not a dominant contributor to the global tendency. These results show the potential of multiple satellite observations to help quantify the spatially resolved response of productivity and respiration fluxes to climate variability.