SPi for January 2006

Fig.17.6b. Monthly monitoring of rainfall anomaly in the Brazilian territory as indicated by the SPI for 0ctober/05 to Ianuary/06.

their duration (Figure 17.6 a; and Figure 17.6 b), which is presented below in the sequence of figures corresponding the months from June 2005 to January 2006. Extreme precipitation negative indices as indicated by the SPI value were observed during this period up to the month ofNovember 2005.

tte severe drought experienced in the southern regions of Brazil during the summer of 2005 caused important economic losses to the region, which has its key agricultural cycle from October to March, ttis drought is well represented in Figure 17.7 and shows the SPI-3 index calculated for February 2005 (which considers the accumulated precipitation from December 2005 to February 2006).

As a result of this adverse phenomenon observed in 2005, during the 2006 crop growing season , INMET adopted a special procedure for follow-up, based on the monitoring of the total accumulated precipitation measured on a daily, monthly, quarterly, semesterly timescale in the stations that the Institute maintains in that region (Anuncia^ao and Fortes 2006). ttis enabled keeping the authorities responsible for agriculture in the country alert to the repetition trends for the phenomenon and provided subsidies for decision making concerning preventive and mitigating measures.

tte southeastern region of Brazil presents a severe history of critical drought periods that often caused serious economic and social losses. Even though the values observed in Figures 17.2 and 17.3 indicate a punctual oscillation of the SPI and PDSI for some locations, they did not quantify the magnitude of this adverse event on a spatial scale.

As example, the 1963 and 1964 periods were extremely dry in this region, as indicated in Figures 17.8 and 17.9 where we have the SPI on a monthly scale (SPI-1) for the month of December 1963 and on an annual scale (SPI-12) for March 1964. It can be noted that the SPI values indicate very severe conditions with negative effects on agriculture, and very serious on water resources, indicating that the socioeconomic losses were extremely severe, tte figures obtained, inferior to -2.0, reflect a likelihood of occurrence of 2 to 3 times every 100 years, ttis phenomenon occurred again in the 2004/2005 period, and this rainfall anomaly based on the SPI values in a month analysis is presented in Figure 17.10. Such results have shown for the State authorities the importance of drought monitoring and the proposed mitigation aspects to reduce the social impact of this phenomenon.

Perspectives for the summer of 2005/2006, based on precipitation data observed and the climatic prognosis for the January/March quarter 2006 were analyzed in greater detail by INMET. Long dry periods in the southern region of the country were observed, most notably in the State of Rio Grande do Sul, severely penalizing the agricultural crops and resulting in economic difficulties to a large number of producers.

tte assessment presented below is based on the monitoring of the total accumulated precipitation measured on a daily, monthly, quarterly, 6-month basis in the INMET weather stations located respectively in Passo Fundo northern region of the state; Santa Maria, Central Region, and Bage, southern region of the state as pointed on the map in (Figure 17.11) defines, by black circles, the three stations considered, tte deviation of the precipitation throughout 1, 3 and 6 months is assessed by means of the Standardized Precipitation Index (SPI). ttis monitoring enabled forecasting of meteorological droughts and the issuance of alerts to deci-

Fig. 17.7. Rainfall anomaly for the period December 2005 to February 2006 as indicated by SPI, in a quarter analysis (SPI-3).

sion makers. Monitoring of the accumulated precipitation in the 1 and 6-month periods facilitated the comparison of the current behavior with that of previous years, as well as the formulation of a prognosis for the coming years. Figure 17.11 indicates that in the September-November quarter in 2005, the precipitation index was situated slightly above the average for Passo Fundo and Santa Maria and within the average for Bage. tte trend for the subsequent months was subsequently analyzed for each station separately. In this sense, the concern was using the available data in order to provide subsidies for the decision making process within the Ministry of Agriculture. As a result, the handling of each case was not homogenous; in fact, there is more information available for Santa Maria, which has been studied for longer period of time. In the future updating of this work, the treatment will be uniform.

Considering climate prediction and prognoses of the rainy season, the National Meteorological Institute (INMET), and the National Space and Research Institute

Fig. 17.8. Variation of SPI on a monthly scale (SPI-1) for the month of December 1963 in the State of Sao Paulo.
Fig. 17.9. Variation of SPI on and yearly scale (SPI-12) for the month of March 1964 in the State of Sao Paulo.

Fig. 17.10. Rainfall anomaly for the period October 2001 in Sao Paulo State based on the SPI values (SPI-1).

Fig. 17.10. Rainfall anomaly for the period October 2001 in Sao Paulo State based on the SPI values (SPI-1).

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