Spatial variability of diurnal to seasonal cycles of precipitation from a high-altitude equatorial Andean valley to the Amazon Basin

2021

Article référencé dans le Web of Science WOS:000712249000002

Ruiz-Hernandez J. C., Condom Thomas, Ribstein P., Le Moine N., Espinoza J. C., Junquas Clémentine, Villacis M., Vera A., Munoz T., Maisincho L., Campozano L., Rabatel A., Sicart Jean-Emmanuel

Journal of Hydrology : Regional Studies, 2021, 38, 100924 [16 p.]

Study region: The upper part of the Guayllabamba and Napo basins (78.2 degrees W, 0.3 degrees S; 18,500 km(2)) in the equatorial Andes, which are vulnerable to stress on the ecosystem services. Study focus: This paper analyses the diurnal cycle of precipitation over a transect from the Andes to the Amazon. The diurnal cycle is estimated as the diurnal distribution of precipitation for 2014-2019 using records from 80 stations. Cluster analysis performed on the diurnal cycle estimates depicts the spatial association between the diurnal and seasonal cycles of precipitation. New hydrological insights: A northwest-southeast spatial variation in the diurnal and seasonal cycles is identified with four groups of stations. In the western part, the seasonal cycles of Groups 1 and 2 are bimodal with precipitation maxima in the March-April and October-November seasons and a short drier season in July-August. In the eastern part, Group 3 also presents bimodality, but a weaker seasonal cycle. Conversely, Group 4 is unimodal with a peak in June. Distinct diurnal cycles are observed in both drier and wetter seasons of Groups 1-3; no marked diurnal cycle is observed in Group 4. Groups 3 and 4 are the most spatially heterogeneous, with an exceptional horizontal variation of 330 mm/yr/km. The analysis of these variations provides insight into the atmospheric dynamics driving precipitation in this zone, and may help to better optimize the water supply system.

Hydrologie [062]

EQUATEUR ; ANDES

Fonds IRD [F B010083318]

fdi:010083318