artículo científico
Moisture transport and seasonal variations in the stable isotopic composition of rainfall in Central American and Andean Páramo during El Niño conditions (2015-2016)
Fecha
2019Registro en:
1099-1085
10.1002/hyp.13438
Autor
Esquivel Hernández, Germain
Mosquera, Giovanny M.
Sánchez Murillo, Ricardo
Quesada Román, Adolfo
Birkel Dostal, Christian
Crespo, Patricio
Célleri, Rolando
Windhorst, David
Breuer, Lutz
Boll, Jan
Institución
Resumen
High‐elevation tropical grassland systems, called Páramo, provide essential ecosystem
services such as water storage and supply for surrounding and lowland areas.
Páramo systems are threatened by climate and land use changes. Rainfall generation
processes and moisture transport pathways influencing precipitation in the
Páramo are poorly understood but needed to estimate the impact of these changes,
particularly during El Niño conditions, which largely affect hydrometeorological conditions
in tropical regions. To fill this knowledge gap, we present a stable isotope
analysis of rainfall samples collected on a daily to weekly basis between January
2015 and May 2016 during the strongest El Niño event recorded in history
(2014–2016) in two Páramo regions of Central America (Chirripó, Costa Rica) and
the northern Andes (Cajas, south Ecuador). Isotopic compositions were used to
identify how rainfall generation processes (convective and orographic) change seasonally
at each study site. Hybrid Single Particle Lagrangian Integrated Trajectory
model (HYSPLIT) air mass back trajectory analysis was used to identify preferential
moisture transport pathways to each Páramo site. Our results show the strong
influence of north‐east trade winds to transport moisture from the Caribbean Sea
to Chirripó and the South American low‐level jet to transport moisture from the
Amazon forest to Cajas. These moisture contributions were also related to the formation
of convective rainfall associated with the passage of the Intertropical Convergence
Zone over Costa Rica and Ecuador during the wetter seasons and to
orographic precipitation during the transition and drier seasons. Our findings provide
essential baseline information for further research applications of water stable
isotopes as tracers of rainfall generation processes and transport in the Páramo and
other montane ecosystems in the tropics.