EGU2020-20625, updated on 15 May 2024
EGU General Assembly 2020
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

The annual and diurnal cycles of precipitation over an Equatorial Andean valley and its transition to the Amazon Basin: A case at the Antizana region

Jean Carlos Ruiz1, Jhan Carlo Espinoza2, Clementine Junquas2, Thomas Condom2, Marcos Villacís3, Pierre Ribstein1, Nicolas Le Moine1, Lenin Campozano3, Andrea Vera4, Teresa Muñoz5, and Luis Maisincho6
Jean Carlos Ruiz et al.
  • 1Sorbonne Université, UMR 7619 METIS, Case 105, 4 place Jussieu, F-75005 Paris, France
  • 2Univ. Grenoble Alpes, IRD, CNRS, Grenoble INP, Insitut des Géosciences de l’Environnement (IGE, UMR 5001), 38000, Grenoble, France
  • 3Escuela Politécnica Nacional (EPN), Departamento de Ingeniería Civil y Ambiental, Quito 170525, Ecuador
  • 4Fondo para la Protección del Agua (FONAG), Quito, Ecuador
  • 5Empresa Pública Metropolitana de Agua Potable y Saneamiento (EPMAPS–Agua de Quito), Quito 17-03-0330, Ecuador
  • 6Instituto Nacional de Meteorología e Hidrología (INAMHI) Iñaquito N36-14 y Corea, Quito, Ecuador

The spatiotemporal variability of precipitation over the complex topography of the Andean equatorial regions has recently caught the attention of researchers thanks to improvements in monitoring networks, including high temporal resolution data. Using a set of 38 rain gauges at hourly time step spanning the 2014-2015 period, this work aims to characterize the annual and diurnal cycles over the upper parts of the Guayllabamba (Andean valley) and Napo (transition zone) basins (78.65°W-77.75°W and -0.8S-0°, land area of ~10000 km2). This region drains respectively to Pacific and Amazonian rivers and is of particular interest because the region provides over 30% of the domestic water demand of the city of Quito, and presents a high glacierized volcano, the Antizana.

The annual cycle is characterized through cluster analysis of monthly rainfall showing two groups of stations that respond to bimodal and unimodal seasonal regimes and corresponds to the local boundary between the Pacific and the Amazon basins. The bimodality presents higher rainfall occurring during March-April and October-November, on the other hand, the unimodality presents its maxima in June.

A careful analysis of the evolution of the diurnal cycle during the year is done and results show that stations with bimodal annual regime peaks around 13:00-17:00 LT and in some months a second peak appears around 22:00-06:00 LT. Regarding stations with unimodal annual regime, the diurnal cycle peaks around 10:00 LT-18:00 LT and in addition shifts to 00:00-06:00 LT during June-August.

In general, the annual and diurnal cycles are useful for water management in the study zone, especially with regards to Quito’s water supply. Furthermore, the annual cycle and its relationship with altitude provides new information related to strong and weak precipitation gradients that are useful for hydro-glaciological modelling exercises. And the information on the diurnal cycle can improve some water management practices.

How to cite: Ruiz, J. C., Espinoza, J. C., Junquas, C., Condom, T., Villacís, M., Ribstein, P., Le Moine, N., Campozano, L., Vera, A., Muñoz, T., and Maisincho, L.: The annual and diurnal cycles of precipitation over an Equatorial Andean valley and its transition to the Amazon Basin: A case at the Antizana region, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20625,, 2020.


Display file