Banca de DEFESA: LUCIANNE FARIAS DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LUCIANNE FARIAS DA SILVA
DATE: 06/09/2023
TIME: 09:00
LOCAL: http://meet.google.com/cgr-ahuy-rod
TITLE:

INFLUENCE OF EL NIÑO-SOUTHERN OSCILLATION (ENOS) ON CO2 CONCENTRATION AND EVASION AT THE AMAZONAS RIVER MOUTH

KEY WORDS:

Carbon cycle. Amazon estuary. Climate changes.

PAGES: 65
BIG AREA: Outra
AREA: Ciências Ambientais
SUMMARY:

The study investigated the influence of the El Niño-Southern Oscillation (ENSO) phenomenon and its different phases (El Niño - EN; La Niña - LN) on the concentration and evasion of CO2 at the mouth of the Amazon River, analyzing the influence of hydrodynamics and biogeochemical parameters that act as forcing the flow of CO2 (FCO2). For this, CO2 flow and partial pressure (pCO2) data were analyzed, in addition to hydrodynamic data collected for the period between 2010 and 2019 in the TROCAS project, specifically in a transect of the North Channel near the mouth of the Amazon River. Precipitation measurements were obtained from the National Institute of Meteorology (INMET) database for the Óbidos and Macapá stations, as well as the exact period of occurrence of the ENOS phenomena, from the Center for Weather Forecast and Climatic Studies of the Institute National Institute for Space Research (CPTEC/INPE). Annual and quarterly anomalies for precipitation were calculated and the relationship with ENSO at the respective stations was investigated for the period of 49 years (Óbidos) and 55 years (Macapá). Non-parametric tests were performed to evaluate the variation and relationship of the studied biogeochemical and meteorological variables. The results showed that in 1983 the largest negative anomalies for precipitation were recorded in both stations, coinciding with strong EN. As for the quarterly anomalies, Óbidos correlated with the occurrences of ENSO. Regarding the flow, it was possible to verify the influence of ENSO on the water discharges of Óbidos, observing a difference of 95,000 m³ s-1 between the peak of highest and lowest flow. pCO2 was the parameter that best correlated with the variables, showing a positive relationship with the flow (rs = 0.80; p < 0.01; rs = 0.90; p < 0.01) and rainfall in Macapá (rs = 0.70; p < 0.01). On the other hand, the FCO2 correlated with the flow measured in Óbidos (rs = 0.52; p < 0.01), but not in the North Channel in Macapá. When analyzing the influence of ENSO on pCO2 and FCO2, it was found that for both variables, the highest coefficients occurred in periods of neutrality in relation to the occurrence of ENSO. Although the averages observed in LN conditions are higher than in the EN phases, no significant difference was obtained between them, but the results indicate that ENSO influences pCO2 and FCO2 even on a small scale. For seasonal variations, significant differences were observed between hydrograph periods, in which the highest pCO2 concentrations were obtained during the high period, which is the expected behavior. For the FCO2, greater evasions were registered in the falling period. Despite this, FCO2 correlated with pCO2 (rs = 0.68; p < 0.01), indicating that it was strongly influenced by pCO2 variability. Finally, considering the absence of evidence of a statistically significant difference between the neutrality intervals and EN and LN conditions, it was not possible to verify in the present study, for the analyzed conditions, that ENOS influences the concentration and evasion of CO2 at the mouth of the river Amazon.

COMMITTEE MEMBERS:
Presidente - 1549120 - RODRIGO DA SILVA
Interno - 2375222 - LUCAS VAZ PERES
Externa à Instituição - SARAH SUELY ALVES BATALHA
Externo à Instituição - ALAN CAVALCANTI DA CUNHA - UNIFAP