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Previous issue date: 2014-08-15 / A an?lise de s?ries temporais tem desempenhado um papel cada vez mais importante em
estudos de tempo e clima. O sucesso desses estudos depende fundamentalmente do
conhecimento da qualidade de dados clim?ticos, como temperatura do ar e precipita??o. Por
essa raz?o, um dos principais desafios para os pesquisadores nessa ?rea ? obter s?ries
homog?neas. Uma s?rie temporal de dados clim?ticos ? considerada homog?nea quando as
varia??es nos dados se devem somente a fatores clim?ticos, sem interfer?ncia de agentes
externos. Tais fatores n?o clim?ticos podem produzir efeitos indesej?veis nas s?ries
temporais, como quebras de homogeneidade, tend?ncias e descontinuidades que na realidade
n?o existem. Neste trabalho foram investigadas s?ries clim?ticas para o munic?pio de Natal ?
RN, representando temperatura do ar e precipita??o, para o per?odo de 1961 a 2012. O
objetivo foi realizar uma an?lise a fim de verificar a exist?ncia de pontos de quebra de
homogeneidade e de tend?ncias nas s?ries estudadas. Para esse fim, foram usados alguns
procedimentos estat?sticos b?sicos, como testes de normalidade e de independ?ncia. Os testes
de tend?ncia foram feitos atrav?s da an?lise de regress?o linear e dos testes de Spearman e de
Mann-Kendall. Para an?lise de homogeneidade, foram usados essencialmente os testes SNHT,
Eeasterling-Peterson e Mann-Whitney-Pettit. As an?lises com respeito ? normalidade
mostraram diverg?ncia em seus resultados. O teste de Von Neumann mostrou que para a s?rie
de temperatura os dados n?o s?o independente e identicamente distribu?dos (iid), ao passo que
para a s?rie de precipita??o os dados s?o iid De acordo com os testes realizados, ambas as
s?ries apresentam tend?ncias. A s?rie de temperatura m?dia do ar apresenta tend?ncia
crescente, enquanto a s?rie de precipita??o acumulada apresenta tend?ncia decrescente.
Finalmente, os testes de homogeneidade revelaram que nenhuma das s?ries ? homog?nea,
embora que os pontos de quebras dependam do teste aplicado. Em geral, os resultados
mostram que as aplica??es das t?cnicas escolhidas permitem caracterizar bem as s?ries
estudadas. Portanto, esses resultados poder?o servir de base para futuros trabalhos sobre a
climatologia de Natal, assim como de outros lugares. / 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.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/20190 |
| Date | 15 August 2014 |
| Creators | Lima, Patr?cia Viana de |
| Contributors | 77231295720, Barbosa, Humberto Alves, 79813801468, Spyrides, Maria Helena Constantino, 79203183434, Mendes, M?nica Cristina Dami?o, 02318221464, L?cio, Paulo S?rgio |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM CI?NCIAS CLIM?TICAS, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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