http://www.americanscientist daht org/articles/02articles/orlove.html
Ethnoclimatology in the
Andes
A cross-disciplinary study
uncovers a scientific basis for the scheme Andean potato farmers traditionally
use to predict the coming rains
Benjamin S.
Orlove, John C. H. Chiang and Mark A. Cane
Keywords:
Climatology, El Niņo, Andes, potato
agriculture, weather prediction, Aymara, Quechua, Pleiades
Abstract:
For at least the past four
centuries, indigenous potato farmers of the Peruvian and Bolivian Andes have
gathered in midwinter to gaze up into the night sky and observe the Pleiades. If
this star cluster appears big and bright to them, they think that they will have
plentiful rains and big harvests the next summer; if the cluster appears small
and dim, they anticipate less abundance. Their belief is so strong that they
time the planting of their crops accordingly. One might imagine that this
practice amounts to nothing more than an odd superstition, but it turns out that
this scheme actually works: The apparent size and brightness of the Pleiades
varies with the amount of thin, high cloud at the top of the troposphere, which
in turn reflects the severity of El Niņo conditions over the Pacific. Because
rainfall in this region is generally sparse in El Niņo years, this simple method
provides a valuable forecast, one that is as good or better than any long-term
prediction based on computer modeling of the ocean and
atmosphere.
Fascinating article! The authors credit amateur astronomers with suggesting plausible mechanisms.