Brazilian Rainforest Rainfall Rates in Response to ENSO & the Interaction with Decadal Scale Oscillations
The Brazilian rainforest is home to one of the Earth's largest carbon dioxide (CO2) sinks. Some studies have linked recent droughts to interannual increases in global CO2 concentrations. When there is drought in the Amazon, there is an increase in understory fires, and the forest no longer stores CO2, but rather emits it (Alencar et al., 2006.) Previous research looks at El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) with respect to the effects it has on the weather in North America. There has been some research regarding the effect these oscillations have on South America, namely Brazil; however, it is focused primarily on the semi-arid Nordesté (Wagner 1997.) Wang, H., Kumar, Wang, W., and Xue (2012) look at the influence of ENSO on PDO through model-based research. Their work separates episodes by sea surface temperature (SST) variations so as to better identify PDO characteristics and Pacific decadal variability (PDV) in the absence of tropical ENSO variability (and North Pacific Gyre Oscillation (NPGO) which will be overlooked in this study.) This study looks at the ENSO-related rain rate anomalies based on National Center for Environmental Prediction (NCEP) data and ground-station data from National Climatic Data Center (NCDC) a subdivision of National Oceanic and Atmospheric Administration (NOAA) from the entire 20th century in the Brazilian Rainforest. This data is evaluated statistically, looking at how the anomalies are specifically controlled by ENSO and the interactions of ENSO with PDO when these episodes occur simultaneously. Additionally, this study looks at anomaly enhancements forced by the North Atlantic Oscillation (NAO.) If a futurecast can be formed based on the knowledge of global oscillation interactions, there is the hope of drought mitigation for the region.