Relation of the El Niño and La Niña Phenomena with a Precipitation and Flow in the Western Amazon Basin
Name: MARKS MELO MOURA
Publication date: 21/07/2017
Advisor:
Name |
Role |
|---|---|
| ALEXANDRE ROSA DOS SANTOS | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| ALEXANDRE ROSA DOS SANTOS | Advisor * |
| NILTON CESAR FIEDLER | Internal Alternate * |
| RODRIGO SOBREIRA ALEXANDRE | Internal Examiner * |
| SAMUEL FERREIRA DA SILVA | External Examiner * |
Summary: The changes in climatic variables verified in periods with the occurrence of El Niño and La Niña phenomena and in neutral periods can be used to monitor changes in climatic variables over the years in the river basins. The objective of this study was to evaluate the individual flow behavior of four sub-basins (rio Javari, rio Purus, rio Auatí-Paraná e lago Coari and rio Javari e Auatí-Paraná), in the Amazonas river basin, Areas covered by snow in Peruvian territory, comparing them with the El Niño and La Niña climatic phenomena, precipitation and evapotranspiration, between January 2000 and December 2016. The study area is located between latitudes 3°9'23''S up to 19°28'37''S and lengths 61°22'03''W to 80°02'54''W. In Brazil, 4 sub-basins were chosen in the Amazonas river basin delimited according to the level 2 ortho-basins of the National Water Agency. For the flow data, we used 47 fluviometric stations inserted within the 4 sub-basins, WHERE the stations were initially separated according to their location and, in this way, the flows were analyzed for each sub-basin individually. Rainfall data were obtained by means of the TRMM sensor (3B43), and the precipitation values were initially extracted for each sub-basin. The evapotranspiration, the Niño Oceanic Index and the snow cover in the Peruvian Andes were acquired, respectively, from the GLDAS sensor (GLDAS_NOAH025_M.020), the NOAA site and the MODIS sensor (MOD10A2). After the initial pre-processing of the data, simple, multiple linear regression, simple correlation and principal component analysis were performed. Based on the results obtained, a weak correlation between the flows and the areas covered by snow was verified for the four sub-basins. However, rainfall averages between the years studied showed a decrease in the periods with the occurrence of the El Niño phenomenon. For the analysis of main components, a similarity was observed between the flows, rainfall and area covered by snow. In this sense, simple linear regressions showed a higher coefficient of linearity between flow rates and precipitation for the 4 sub-basins studied. It is concluded that the rainfall indexes had a greater influence on the outflows in the sub-basins than the changes in the areas covered by snow. In addition, the lower values of flow were observed in the periods with influence of the El Niño phenomenon, while the highest values for the flow were obtained in neutral periods. The proposed methodology can be adapted to other areas or river basins.
Keywords: remote sensing, climate change, temporal analysis.
