Banca de DEFESA: IRIS LAYANNE NOBRE FRANCA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : IRIS LAYANNE NOBRE FRANCA
DATE: 22/06/2022
TIME: 08:30
LOCAL: videoconferencia
TITLE:

EFFECT OF CLIMATE VARIABILITY ON LOW LEVELS OF RESERVOIRS IN THE SÃO FRANCISCO RIVER HYDROGRAPHIC BASIN

KEY WORDS:

 Drought, Mann-Kendall, Wavelets, Trends.

PAGES: 98
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUBÁREA: Meteorologia
SUMMARY:

The number of occurrences of extreme precipitation events has increased over the last few years, occurring, in some cases, with greater intensity and duration, thus favoring natural disasters such as severe droughts. Therefore, the expansion of knowledge about the quantity/frequency of rain that falls in a region is fundamental for the strategic planning of local and regional water resources. In this context, this research aims to analyze the level of the main reservoirs of the four sub-basins that make up the São Francisco River Basin, identifying rainfall events, particularly drought, and their possible climatic causes. The study was carried out with precipitation and quota data from four pluviometric and four fluviometric stations, respectively, representative for each variable, obtained through the National Water Agency (ANA) for the period from 1968 to 2020. Extreme drought events were classified and characterized by the standardized precipitation index (SPI), in addition to identifying years of greater precipitation deficits. The Mann-Kendall test was used to detect climatic trends in rainfall series in the four sub-regions of the BHSF and were statistically analyzed using the Student's T test. Of the four sub-regions, three of them show a downward trend in precipitation and quota, while only one shows an increase trend, highlighting the possible changes in the sub-regions' reservoir levels. Ondaletas analysis was used with the intention of verifying extreme rainfall cycles and their causes through the temporal scales observed in the precipitation series of the BHSF sub-regions. Preliminary results show that all sub-regions have higher occurrences of droughts than rains, however, extreme drought events are infrequent, whereas mild drought events were more recurrent. The years characterized as almost normal, that is, with values close to the average rainfall for the region, were the ones with the highest number in the four sub-regions, however, in all of them, the mild drought episodes had significant percentages. To identify possible climatic causes, Wavelet Analysis was used. It was found that the seasonal and interannual scales dominated, associated with the persistent El Niño Southern Oscillation sign (7 years). With information on the influence of temporal cycles on precipitation in the BHSF sub-regions, it is possible to visualize the impact of climatic phenomena on the water reserve of the Basin. In relation to the annual averages, two major climatic groups were formed that are indirectly similar to each other. 

BANKING MEMBERS:
Presidente - 1772619 - DJANE FONSECA DA SILVA
Externo ao Programa - 2570329 - HENRIQUE RAVI ROCHA DE CARVALHO ALMEIDA
Interna - 1653612 - MARIA LUCIENE DIAS DE MELO