Precipitation dynamics and chemical properties in tropical mountain forests of Ecuador

摘要

Terrestrial ecosystems in southern Ecuador are strongly affected byinterannual climate variations. This holds especially true for the episodicEl Niño events, which cause above-normal precipitation in the coastalregion of Ecuador and below normal values in the eastern provinces of theAmazon basin (Bendix, 1999). For the transitional zone between these twoextremes, which consists mainly of the andean slopes and larger interandeanbasins the effect on interannual climate variability is not well known.

The PREDICT project monitors regional climate in the provinces of Loja andZamora-Chinchipe (4° S/79° W), where a strong gradients ofprecipitation are observed. Between the eastern slopes of the CordilleraReal and the dry valley of Catamayo, which are only 70km apart, rain totalsdrop from over 4000 mm to only 300 mm per year. These two extremes representthe both sides of the Andean mountain chain and are completely covered bythe study area, which is 120 km in diameter. Methods used are a combinationof point measurements (climate stations) and remote sensing devices (weatherradar, satellite imagery), which enable a high-resolution real-timeobservation of rain distribution and underlying processes. By this, idealconditions are given to monitor a potential shift of the transition zonebetween below-average and above-average rainfall situated in this region, ifanother ENSO-anomaly occurs. Furthermore variability of atmospheric nutrientinputs is analysed within the scope of the project, to assess furtherimpacts on this ecosystem.