IWRA Executive Office

OS3e Regional and nationwide scenarios 1

abstract 128

Melting of low latitude Andean glaciers according to global and local climate variations

Author(s): Eric Cadier, Marcos Villacís, Luis Maishincho, Carla Manciati, Edgar Ayabaca, Bernard Francou
Eric Cadier, Marcos Villacís, Luis Maishincho, Carla Manciati, Edgar Ayabaca & Bernard Francou IRD–INAMHI UR032 Casilla 17.12.857 Quito Ecuador Cadier@ird.fr (+005932) 226.92.76; Fax 2.504.020

Keyword(s): Ecuador, El Niño, glacier melting modelling, tropical glacier

Article:

Poster:

Session: OS3e Regional and nationwide scenarios 1

AbstractIntroduction:
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.

Objectives:
• 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

scenarios.

Methods
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

Results
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)

Conclusions
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.

Events

The congress

Programme

Practical Infos

Melting of low latitude Andean glaciers according to global and local climate variations