Os climas do Rio Grande do Sul : variabilidade, tendências e tipologia

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

2011

RESUMO

This thesis focuses on the analytical study of the climate in the state of Rio Grande do Sul (Brazil), addressing the variability (spatial-temporal) of climatic-meteorological elements and the approach of their trends based on the climate classification in the area. In association with this analysis is the recognition of climate variability in regional scale for 1931-2007. Considering this, the focus is on the update of knowledge related to climatology in Rio Grande do Sul, synthesized from the establishment of a climate classification that incorporates the use of new methodologies and technologies. For this purpose, a climate classification method was developed to contemplate the qualitative and quantitative analyses based on the genetic and dynamic climatology associated with the statistical analysis. The current study was based on the integration between the climate elements and the surface atmospheric circulation (air mass dynamics) related to the statistical and geostatistical techniques. The analysis of climate variability of the area in study for 1931- 2007 (linear and polynomial trends) corroborates the hypothesis that there is a decrease in amplitude between the maximum and minimum temperatures in locations situated in every geomorphologic compartment in the state. However, this fact was identified mostly in the locations in which the minimum temperature increase is greater than the maximum, particularly in the median portion of the north-central area, indicating a small but considerable reduction of cold cores in the state. The analysis of the total annual rain levels revealed the elevation of such levels with a trend towards concentration. Although warming trends and increased precipitation were observed in the area, they were statistically insignificant, since the correlation coefficients found ranged from weak to moderate. With respect to the climate regime, it was observed that the polar systems in interaction with tropical systems have great influence on the climates of the state; however, it is the combination with the local and regional geographical factors that sets the spatial variability of the climate elements. The genesis of rainfall is primarily associated with the frontal systems. With respect to the climate typology, the state of Rio Grande do Sul is located in the domain area of subtropical climate, subdivided into four main types: Subtropical I - moderately humid (Subtropical Ia ¿ moderately humid with cold winter and cool summer and Subtropical Ib ¿ moderately humid with cold winter and hot summer); Subtropical II: Moderate humidity with longitudinal variation of average temperatures; Subtropical III: humid with longitudinal variation of average temperatures; and Subtropical IV- Very Humid (Subtropical IVa very humid with cool winter and hot summer and Subtropical IVb ¿ very humid with cold winter and cool summer). Clearly, the state of Rio Grande do Sul has climatically different regions showing certain heterogeneity, unlike most of the best-known climate classifications of the state.

ASSUNTO(S)

climatologia rio grande do sul variability rio grande do sul trends typology climate

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