Banca de QUALIFICAÇÃO: FELIPE JEFERSON DE MEDEIROS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : FELIPE JEFERSON DE MEDEIROS
DATA : 29/04/2019
HORA: 08:30
LOCAL: Auditório CCET
TÍTULO:

DYNAMIC CHARACTERISTICS OF ATMOSPHERIC PATTERNS ASSOCIATES OF THE DROUGHT OF 2012-2016 IN THE NORTHEAST OF BRAZIL: OBSERVATIONAL AND NUMERICAL STUDY

PALAVRAS-CHAVES:

Atmospheric circulation. Drought. El Niño. Downscaling. RegCM4.

PÁGINAS: 59
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
SUBÁREA: Meteorologia
ESPECIALIDADE: Climatologia
RESUMO:

Identifying patterns of atmospheric circulation related to the development of drought episodes contributes to the process of mitigating impacts to society. In Northeastern Brazil (NEB), one of the regions most vulnerable to occurrence of extreme events in South America, episodes of droughts are frequently recorded. This was the scenario observed between the years of 2012-2016, in which a severe drought hit the region. It is estimated that in this period approximately 85% of the reservoirs had less than 25% of their maximum capacity, and about 80% of the cities and 33.4 million people were affected by this extreme event. In this context, considering that this episode of drought was probably the most intense and long lasting recorded in the history of NEB, this research proposal aims to analyze the climatic characteristics at regional scale and the teleconnection patterns associated with the extreme event of drought occurred in the NEB during the period from 2012 to 2016, as well as modeling rainfall variability over the same period using the RegCM4 (RegCM-TBAND) regional climate model. In the observational study, data will be used in the 1981-2016 period of precipitation and maximum and minimum temperature provided by Xavier et al., (2016), as well as monthly means of the zonal, southern wind, vertical velocity and specific humidity of the ERA-Interim reanalysis. In addition, Sea Surface Temperature (SST) and Outgoing Long Wave Radiation (OLR) data will be used. The period 1981-2010 will be considered climatological, and from it, the monthly and annual anomalies will be calculated to diagnose the anomalous behavior of the meteorological variables during the period of 2012-2016. Then the dynamic analysis will be performed. In order to do so, the space fields of SST and OLR, and the ascending and descending movements related to Hadley and Walker will be investigated in order to identify the large scale atmospheric mechanisms associated with the dry period. In the numerical study, the simulations will be produced by RegCM-TBAND on the domain from 30 ° S to 30 ° N with horizontal resolution of 30 km. Initially, the skill of the model will be evaluated for the entire domain, for which purpose, ERA5 reanalysis data will be used. Afterwards, a NEB-focused analysis will be carried out to evaluate if the model is capable of reproducing the negative rainfall anomalies in the region. In this step, data from Tropical Rainfall Measuring Mission (TRMM), Global Precipitation Climatology Project (GPCP), Xavier and Climate Research Unit (CRU) will be used. Preliminary results indicated that this drought occurred between 2012-2016 was the most intense since 1981, and the Northern Northeast Brazil (NNEB) is the most affected region. In quantitative terms, the negative precipitation anomalies on the NEB were 1063.4 mm, while on the NNEB were 1395.4 mm. The most affected seasonal season was the austral autumn (MAM), in which an average water deficit of 462.2 mm was detected in relation to the climatology. The analyzes of the maximum and minimum temperature anomaly indicated that in MAM besides the negative precipitation anomalies, an increase in the frequency, with significance of 1%, in the periods of heat and a decrease of the cold nights was observed on the NNEB. The next steps of the research are to obtain the oceanic and atmospheric patterns that caused the drought in the region of study, as well as to initiate the analyzes of the numerical simulations. This study intends to contribute to the improvement of the seasonal forecast of NEB precipitation in years whose atmospheric characteristics are similar to those discussed in the paper. This improvement in seasonal forecasting may lead to several public policies to mitigate the social and economic impacts linked to the occurrence of drought events in NEB.

MEMBROS DA BANCA:
Presidente - 1280761 - CRISTIANO PRESTRELO DE OLIVEIRA
Interno - 1752417 - CLAUDIO MOISES SANTOS E SILVA
Interno - 1164414 - WEBER ANDRADE GONCALVES