Browsing by Author "Ilbay-Yupa, Mercy"

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    Regionalization of precipitation, its aggressiveness and concentration in the Guayas river basin, Ecuador
    (Universidad Politécnica Salesiana, 2019-09-01) Ilbay-Yupa, Mercy; Zubieta Barragán, Ricardo; Lavado-Casimiro, Waldo
    The aggressiveness of rain contributes to the erosion of the soil in high mountain regions, and therefore to the sedimentation in the lower part of the watershed. To know about the aggressiveness of rain in coastal and Andean regions contributes to the formulation of mitigation measures that help to the reduction of erosion and loss of nutrients. Fournier indices, Modified Fournier and precipitation concentration provide the ability to estimate the spatial and temporal distribution of the aggressiveness of the rain. This study presents a spatial and temporal analysis of climatic aggressiveness in the Guayas river watershed located on the coast and the equatorial Andes. Registered monthly data of 30 rainfall stations for the period 1968-2014 was selected. Homogeneous precipitation zones were determined by the k-means method. The results indicated two predominant homogenous regions, the first located to the west in the coastal and Andean zone (85;2% of the area of the Watershed), with a high and very high aggressiveness index, while the distribution of precipitation in the second region (High mountain) resulted from very low to low aggressiveness. The greater potential aggressiveness of rain corresponds to a greater accumulation of average annual rainfall, which indicates a high seasonal influence of rainfall, i.e., a greater amount of rainfall can precipitate in a reduced number of consecutive months. The concentration values reveal a regional gradient in the east-west direction, which goes from moderately to strongly seasonal. The trend analysis of the monthly rainfall concentration shows no significant changes in the study period. However, these findings explain why the western and southern region of the Guayas river watershed is exposed to sedimentation problems in the lower part, due to the erosive capacity of rain in the higher and middle part of the watershed.
    Palabras clave:GuayasConcentrationPrecipitation
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    Updating regionalization of precipitation in Ecuador
    (Springer, 2021-01-07) Ilbay-Yupa, Mercy; Lavado-Casimiro, Waldo; Rau, Pedro; Zubieta Barragán, Ricardo; Castillón, Fiorela
    This article identifies homogeneous precipitation regions in Ecuador and their relationship to the El Niño-Southern Oscillation (ENSO), using monthly records from 215 rain stations for the 1968–2014 period. A k-means clustering analysis was used to divide the study area into k regions based on monthly and annual precipitation variables and geographic location (latitude, longitude, and altitude). The robustness of each cluster was evaluated using the “silhouette” coefficient. The groupings were then validated using the regional vector method (RVM). Twenty-two regions of homogeneous precipitation were identified. Seven regions are related to regional climate processes on the Pacific coast (unimodal precipitation). Two regions in the western foothills of the Andes show significant orographic rainfall. Eight regions in the inter-Andean region present a bimodal precipitation regime characterized by a reduction of precipitation from north to south and local variability. Five regions were identified in the Amazon area: three on the outer flanks of the eastern mountain range, one sub-Andean area, and one in the Amazon plain with regular rainfall throughout the year, influenced by the Amazon basin. Although Tropical Pacific sea surface temperature (SST) is strongly related to precipitation in the coastal regions of Ecuador, our findings indicate that SST influence varies among the regions of the country because Ecuador is influenced by the modes of precipitation variability in Colombia and Peru.
    Palabras clave:RainfallRegionalizationPrecipitation