Agricultural Drought Phenomenon in Latin America with Focus on Brazil - Monitoring and Predicting Agricultural Drought: A Global Study - page 161

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Table 12.2 Climatic classification and aridity index based on
methodology by Thornthwaite and Mather (1955) for distinctive
locations in Argentina, Brazil, Chile, and Paraguay

Country Location Aridity index Climate

Argentina Rivadavia 0.48 Semiarid

Mendoza 0.75 Arid

Chepes 0.66 Arid

Brazil Quixeramobim (NE) 0.48 Semiarid

Petrolina (NE) 0.75 Arid

Jaguaribe (NE) 0.58 Semiarid

Fortaleza (NE) 0.33 Subhumid, humid

Cuiab a (W) 0.13 Subhumid dry

Ribeir ao Preto (SE) 0.09 Humid

Barretos (SE) 0.13 Subhumid, humid

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Campinas (SE) 0.03 Humid

Chile Los Andes 0.63 Semiarid

Patrerilios 0.89 Arid

La Serena 0.79 Arid

Line
——
0.1
——
Norm
PgEn

Antofogasta 0.99 Arid

Paraguay Pedro Pe na 0.54 Semiarid

Nueva 0.54 Semiarid

Mariscal 0.45 Semiarid

D istribution of Dry Spells

The occurrence of dry spells lasting more than 10 days in the month of
January seriously affects the production of field and grain crops, partic-
ularly field and grain crops in the southeastern and central parts of the
country (Alfonsi et al., 1979), and the knowledge of the distribution of the
dry spells is helpful in identifying, quantifying, and mapping droughts in
the region (Arruda and Pinto, 1980).
Drought monitoring and mitigation in Brazil is in its initial stage. Only
the state of S ao Paulo conducts weekly drought monitoring—through its
Integrated Agrometeorological Information Center (CIIAGRO) and the
Instituto Agronômico de Campinas (IAC-APTA) of the Agriculture and
Supply Secretariat (Government of the State of S ao Paulo)—using various
indices (Brunini et al., 1998) that are described below.

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So il Moisture and Potential Evapotranspiration

The ratio of the actual water availability in soil (W) to the maximum
water availability in soil (Wx) and PET can be used to monitor drought
conditions, as shown in table 12.3.
Currently a new index, the agricultural drought index (ADI), as shown
in table 12.4, is being implemented to monitor crop development stages
and drought conditions. The ADI takes into account not only the actual
soil water availability, but also the crop phenological stages and rainfall
distribution.