masterThesis
Análise de métodos para detecção de mudanças estruturais em séries temporais climáticas
Fecha
2014-08-15Registro en:
LIMA, Patrícia Viana de. Análise de métodos para detecção de mudanças estruturais em séries temporais climáticas. 2014. 43f. Dissertação (Mestrado em Ciências Climáticas) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2014.
Autor
Lima, Patrícia Viana de
Resumen
The time series analysis has played an increasingly important role in weather and climate
studies. The success of these studies depends crucially on the knowledge of the quality of
climate data such as, for instance, air temperature and rainfall data. For this reason, one of the
main challenges for the researchers in this field is to obtain homogeneous series. A time series
of climate data is considered homogeneous when the values of the observed data can change
only due to climatic factors, i.e., without any interference from external non-climatic factors.
Such non-climatic factors may produce undesirable effects in the time series, as unrealistic
homogeneity breaks, trends and jumps. In the present work it was investigated climatic time
series for the city of Natal, RN, namely air temperature and rainfall time series, for the period
spanning from 1961 to 2012. The main purpose was to carry out an analysis in order to check
the occurrence of homogeneity breaks or trends in the series under investigation. To this
purpose, it was applied some basic statistical procedures, such as normality and independence
tests. The occurrence of trends was investigated by linear regression analysis, as well as by
the Spearman and Mann-Kendall tests. The homogeneity was investigated by the SNHT, as
well as by the Easterling-Peterson and Mann-Whitney-Pettit tests. Analyzes with respect to
normality showed divergence in their results. The von Neumann ratio test showed that in the
case of the air temperature series the data are not independent and identically distributed (iid),
whereas for the rainfall series the data are iid. According to the applied testings, both series
display trends. The mean air temperature series displays an increasing trend, whereas the
rainfall series shows an decreasing trend. Finally, the homogeneity tests revealed that all
series under investigations present inhomogeneities, although they breaks depend on the
applied test. In summary, the results showed that the chosen techniques may be applied in
order to verify how well the studied time series are characterized. Therefore, these results
should be used as a guide for further investigations about the statistical climatology of Natal
or even of any other place.