El Niño-Southern oscillation and the climate, ecosystems and rivers of Amazonia

摘要: [1] The El Nino–Southern Oscillation (ENSO) phenomenon is one of the dominant drivers environmental variability in tropics. In this study, we examine connections between ENSO and climate, ecosystem carbon balance, surface water river hydrology Amazon Tocantins basins South America. First climatic associated with ENSO. We analyze long-term historical climate records to document “average” signature Nino La Nina phases cycle. Generally speaking, “average Nino” drier warmer than normal Amazonia, while Nina” wetter cooler. While temperature changes are mostly uniform through whole year spatially homogeneous, precipitation stronger during wet season (January-February-March) concentrated northern southeastern portions basin. Next use a land surface/ecosystem model (IBIS), coupled hydrological routing algorithm (HYDRA), how affects fluxes, as well discharge flooding. The results suggest several responses ENSO: (1) During average Nino, there an anomalous source CO2 from terrestrial ecosystems, mainly due decreased net primary production (NPP) north There also decrease along many rivers basin, which causes flooded area main stem Amazon. (2) Nina, sink into largely increase NPP portion addition, large especially western tributaries. corresponding area, rivers. These illustrate that balance have complex, heterogeneous features across This underscores need for comprehensive analyses, using observational data simulations, regional systems their response variability.