The impact of glaciers on the runoff and the reconstruction of mass balance history from hydrological data in the tropical Cordillera Blanca, Perú.
Journal of Hydrology, 282, 130-144.
Georg Kaser*, Irmgard Juen*, Christian Georges*, Jesús Gómez°, William Tamayo°
* Tropical Glaciology Group, Institut für Geographie, Innrain 52, A-6020 Innsbruck, Austria
° Unidad de Glaciologia y Recursos Hidricos, Huaraz, Perú
Abstract
A 41 years series of runoff and precipitation data from the Peruvian Cordillera Blanca demonstrates the high
hygric seasonality in this tropical high mountain range. In this area, glaciers have a crucial impact on runoff
which is of essential importance for the highly populated and cultivated valley of the Callejon de Huaylas
particularly during the dry season. Whereas in the mid latitudes glacier melt amplifies the seasonal variation of
runoff the effect of glaciers in the low latitudes is a smoothing one. It decreases clearly with the decreasing
degree of glaciation. In addition, particular circumstances of this tropical environment allow the reconstruction
of a glacier mass balance history from the hydrological data for the second half of the twentieth century. It shows
a high synchronicity with the global trend of periods with mass loss and gain. Comparison with length variations
of three individual glaciers indicate a rather fast reaction of the glaciers to changes in mass balance. Although the
mass balance varaitions show some differences among the individual catchment basins, the over all trend is
uniform. A general positive correlation of mass balance variations with SOI is obvious but not regular.