Space–time rainfall variability in the Paute basin, Ecuadorian Andes

Abstract

Despite the importance of mountain ranges as water providers, knowledge of their climate variability is still limited, mostly due to a combination of data scarcity and heterogeneous orography. The tropical Andes share many of the main features of mountain ranges in general, and are subject to several climatic influences that have an effect on rainfall variability. Although studies have addressed the large‐scale variation, the basin scale has received little attention. Thus, the purpose of this study was to obtain a better understanding of rainfall variability in the tropical Andes at the basin scal, utilizing the Paute River basin of southern Ecuador as a case study. Analysis of 23 rainfall stations revealed a high spatial variability in terms of: (i) large variations of mean annual precipitation in the range 660–3400 mm; (ii) the presence of a non‐monotonic relation between annual precipitation and elevation; and (iii) the existence of four, sometimes contrasting, rainfall regimes. Data from seven stations for the period 1964–1998 was used to study seasonality and trends in annual, seasonal and monthly precipitation. Seasonality is less pronounced at higher elevations, confirming that in the páramo region, the main water source for Andean basins, rainfall is well distributed year round. Additionally, during the period of record, no station has experienced extreme concentrations of annual rainfall during the wet season, which supports the concept of mountains as reliable water providers. Although no regional or basin‐wide trends are found for annual precipitation, positive (negative) trends during the wet (dry) season found at four stations raises the likelihood of both water shortages and the risk of precipitation‐triggered disasters. The study demonstrates how variable the precipitation patterns of the Andean mountain range are, and illustrates the need for improved monitoring. Copyright © 2007 John Wiley & Sons, Ltd.

Near-Surface Air Temperature Lapse Rate Over Complex Terrain in the Southern Ecuadorian Andes: Implications for Temperature Mapping

“…Although precipitation amount varies with altitude, the pattern is the same throughout the gradient; hence, the data shown in Figure 4 is valid for identifying rainfall seasonality in the study area. These results are in agreement with the patterns found by Célleri et al (2007) using long-term precipitation data in the region.…”

Evolución climática en la costa de Ecuador por efecto del cambio climático

“…El comportamiento de la precipitación en la PSE resulta similar al encontrado en otras zonas de la costa Pacífica Sudamericana, y a pesar de la amplia variabilidad en los resultados de tendencias reportados, con valores de evolución intraanual positivos y negativos [12][13][14], se detectan tendencias regionales de carácter positivo en zonas más próximas a las regiones tropicales y tendencias de tipo negativo en zonas más alejadas de los trópicos [5,8].…”

“…En la costa pacífica de Sudamérica se han desarrollado algunos estudios que analizan la evolución de la temperatura [3][4][5][6][7] y la precipitación [5,[8][9][10][11][12][13][14][15][16] y que han permitido crear una línea base de información para analizar las características del clima actual y su futura evolución. En este sentido, aunque para la temperatura los trabajos detectaron tendencias positivas similares a los encontrados a nivel mundial, son de destacar los valores de negativos de la costa Chilena [3,6].…”

Soil Agricultural Potential in Four Common Andean Land Use Types in the Highlands of Southern Ecuador as Revealed by a Corn Bioassay

“…In these regions, large differences in elevation cause higher orographic precipitation than in the rest of the watershed. The total annual rainfall averages between 1050 mm and 1700 mm [22]. Regions 3 and 4 are located in the south of the Paute watershed.…”

“…Regions 3 and 4 are located in the south of the Paute watershed. Here, total annual rainfall ranges between 660 mm and 1100 mm [22] (Figure 1). According to Buytaert et al [18] the soils in the northern part of the Paute watershed are classified as Histic Andosols (Regions 1 and 2), and as Dystric Histosols in the southern part of the watershed (Regions 3 and 4) because of lower soil Al and Fe content (Figure 1).…”