Trends and variability in extremes of precipitation in Curitiba – Southern Brazil

Abstract

Based on the daily rainfall data since 1889 in Curitiba, one of the largest cities in southern Brazil, a trend towards increased precipitation and more intense rainfall can be seen. The annual and seasonal volume of rainfall has increased, amounts greater than 10, 20 and 40 mm being observed more often, but with a reduction in the number of rainy days and the number of days with rainfall below 10 mm. Seasonal 95th percentile series have increased in summer, fall and winter. In addition, several indices of climate extremes presented significant increasing trends: monthly maximum 1‐day precipitation, annual total precipitation greater than 95th and 99th percentiles, number of consecutive dry days and the daily intensity index. Generalized extreme value (GEV) distribution function parameters also indicated higher occurrence of extremes detected by the increase in both the scale parameter σ and the location parameter μ in summer, fall and winter. The return time for severe rainfall declined in the second half of the period compared to the first, indicating more frequent occurrence of future extreme events. The main climate indices affecting the 95th percentile series were sea surface temperature (SST), South Atlantic Convergence Zone (SACZ) and Southern Oscillation Index (SOI) during spring, and Atlantic Multi‐decadal Oscillation (AMO), Large‐Scale Index for South America Monsoon (LISAM) and SOI during the summer, which explained variability of the extremes at around 20 and 13%, respectively in each season. Regarding the variability of summer, fall and spring total rainfall, they presented values around 20% for the explained variance due to climate indices. Other factors should be investigated to explain the variability such as urbanization, air pollution and local circulations. Dominant oscillation periods in the time series constructed with one monthly extreme appeared at 3 to 8‐year (inter‐annual) cycles, with 12 years (decadal) and around 30–64 years on the inter‐decadal scale. These oscillations have resonance with SOI, SACZ and Southern Annular Mode (SAM) indices (high frequencies), and Pacific Decadal Oscillation (PDO) and AMO (low frequency).

Multiscale Spatio-Temporal Changes of Precipitation Extremes in Beijing-Tianjin-Hebei Region, China during 1958–2017

“…As previous mentioned, changes in precipitation extremes are related to the large-scale circulation change [41,42,[77][78][79]. The periodicity characteristics of precipitation extremes will be helpful to understand their associations or linkages with climate indices, which has been investigated in the other regions in previous studies [40,[60][61][62][63][64][65]. Our results showed that the significant two-to five-year periods at the 5% level were predominant for all the indices during the entire period, which are roughly consistent with the previous work of Wang et al [63].…”

“…Wavelet analysis was widely applied to examine multi-temporal scale features of precipitation extremes or other climate events [59][60][61][62][63][64][65]. Wavelet transform (WT) decomposes time series into time-frequency space and identifies the dominant modes of variability and the characteristics how these modes vary in time [66].…”

Assessing precipitation trends in the Americas with historical data: A review

“…Additionally, patterns of sea surface temperature (SST) anomalies and respective coupled teleconnections may either amplify or reduce the response of the hydrological cycle to the rapid warming (Jones & Carvalho, ). Perhaps more importantly, there is growing observational evidence indicating that extreme precipitation events have increased in several areas of South America, whereas other regions have been subjected to drought conditions since the middle of the 20th century (Boulanger et al, ; Cavalcanti et al, ; Chen et al, ; Donat et al, ; Haylock et al, ; Heidinger, Carvalho, Jones, Posadas, & Quiroz, ; Marengo, ; Marengo, Rusticucci, Penalba, & Renom, ; Marengo, Tomasella, Alves, Soares, & Rodriguez, ; Pedron, Silva Dias, de Paula Dias, Carvalho, & Freitas, ; Penalba & Robledo, ; Sena, Silva Dias, Carvalho, & Silva Dias, ; Silva Dias, Dias, Carvalho, Freitas, & Dias, ; Zilli, Carvalho, Liebmann, & Silva Dias, ; Zilli, Carvalho, & Lintner, ).…”

Variability and Factors of Influence of Extreme Wet and Dry Events in Northern Mexico

“…In the coming decades, the effects of climate change will be reflected around the world in rainfall irregularity, increased maximum temperatures [1], and evapotranspiration, which could cause extreme wet [2] and dry [3] events.…”