IWRA World Water Congress 2008 Montpellier France
3. Climate Change and Disasters
Eric Cadier, Marcos Villacís, Luis Maishincho, Carla Manciati, Edgar Ayabaca & Bernard
IRD–INAMHI UR032 Casilla 17.12.857 Quito Ecuador Cadier@ird.fr (+005932) 226.92.76; Fax
Ecuador, El Niño,
glacier melting modelling, tropical glacier
Tropical glaciers shrinkage is generalised and has been accelerating since
the end of the 1970s, especially during warm phases of El Nino events. Several authors have shown the links
between the Andean climate, the glaciers retreat and the global climate variations. Locally, ice loss processes
(melting and sublimation) are complex and dependent on several variables like temperature, air humidity, wind, cloud
cover, incident and reflected radiations on the glacier surface (thus of albedo), while its maintenance depends upon
precipitation influence. But direct measurements upon glaciers are scarce and we shall try to replace them by data
from meteorological station located in similar climatic situation.
• Set up models
showing the links and the respective influence of climatic parameters upon glaciers variations.
• Use and
calibrate these models to reproduce the past glacier and climate variations.
• Use these models to project
future glaciers and water resources evolution, according to the main IPPC climate
Establish the links and the models between local (data collected close to the glacier),
regional (data collected in Ecuador by the meteorological network or by remote sensing) and global (i.e. ENSO
index) climatic information at daily and monthly time scale.
Select the most pertinent models considering data
availability to realise the long term calibration and simulation
Using twelve years of mass balance,
meteorology, precipitation and runoff data on two glaciers located on the Antizana volcano (Ecuador) very close to
equator, we studied the relations of daily and monthly melting of the glaciers with 50 variables chosen to represent
the global, regional and local climate.
Various models were produced. One of them explains 58% of the melt
variance. This model implicates the Niño3+4 index as well as precipitation anomalies at the foot of the Antizana.
Excess (lack) of precipitation during the 9 previous months will incite a decrease (increase) of melting. A warm
(cool) anomaly of the ENSO oscillation will incite an increase (decrease) 4 months later.
Another model explains
54% of the melt variance using only temperature data from the oldest Ecuadorian meteorological station ("Quito
Observatorio", observed since 1892)
These models constitute now one of the tools that
suggest and facilitate the comprehension of the links between several climatic mechanisms. They permit generate
future glacier and water resources evolutions according to the main IPPC climate scenarios.