Climate Exchange

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griculture

months will enable farmers and decision-makers to take

adequate actions in advance for mitigating the possible

impacts of meteorological conditions in their different

management areas, or for adapting measurements to

benefit from them.

DMC began to make seasonal predictions (three

months) for precipitation and extreme air tempera-

tures for Chile in 2000. Initially, it used conventional

statistical technique such as simple linear regression,

considering the SST, the accumulated precipitation and

average minimum and maximum air temperatures for

Chilean stations as predicting variables. Later in 2003,

the Climate Predictability Tool (CPT) developed by the

International Research Institute for Climate and Society

(IRI) at the University of Columbia was incorporated.

mechanism that, in part, controls the seasonal climate variability,

mostly in central Chile (28-40°). Increasing the sea surface tempera-

ture (SST) above normal (El Niño) or decreasing below normal (La

Niña) in the central-equatorial Pacific ocean, can originate changes

in atmospheric circulation in the Southern Hemisphere that can

favour or inhibit precipitation events in the central, as well as in the

northern and southern regions of Chile.

Thus, seasonal climate prediction in Chile is mainly based on

changes in the SST that take place in the central equatorial Pacific

Ocean (known as El Niño 3.4), and its prediction is produced using

global numerical climate models. The variability of the atmospheric

conditions affecting the country, at different spatial and time scales

has a significant impact on agriculture in the central region, where

the main activity is located.

Knowing the precipitation and air

temperature behaviour that will most likely prevail for the next three

Source: DMC

A climate forecast for precipitation accumulation corresponding to October 2012,

using the Climate Mesoscale Model - version 5