Multiple constraints on regional CO2 flux variations over land and oceans

Abstract

To increase our understanding of the carbon cycle, we compare regional estimates Of CO2 flux variability for 1980-1998 from atmospheric CO2 inversions and from process-based models of the land (SLAVE and LPJ) and ocean (OPA and MIT). Over the land, the phase and amplitude of the different estimates agree well, especially at continental scale. Flux variations are predominantly controlled by El Niño events, with the exception of the post-Pinatubo period of the early 1990s. Differences between the two land models result mainly from the response of heterotrophic respiration to precipitation and temperature. The "Lloyd and Taylor" formulation of LPJ [Lloyd and Taylor, 1994] agrees better with the..