Methodological procedure for analyzing the distribution of rain and the water balance in semiarid extract: Case study

Abstract

For the semiarid region, information of water conditions are indispensable to establish management strategies of agricultural production. Thus, aimed to define a methodological procedure for variability analysis and anomaly of rain and of the sequential climatic water balance (SCWB) extract, and your trends change over time. They were used rainfall data for the municipality of Carnaíba-PE, referring to the series from 1965 to 2006 and subsequently submitted to descriptive statistics, and proposed a methodology to detect variability and climate anomalies by deviations of rainfall. Then proceeded with trend analysis of annual and monthly data are significant since p<0.10. The results showed that the highest annual rainfall was 1921.5 mm and less than 49.6 mm. There was a significant trend of reducing precipitation only June (p <0.05) and the annual values (p<0.10). It was diagnosed 45% of the years were classified in the "Years Normal" class, and in the months of August, September and October, the number of lower anomalies was higher than 50%. In relation to SCWB only the components water deficit and ground water withdrawal showed significant trends. It was found that between the years 1965 and 2006, the variability and climate anomaly of rain events, below normal climatological were more frequent events, however, it is due to its occurrence in the driest months  and that there were annual and monthly fluctuations in SCWB components over the years analyzed, indicating high variability of local rain regime.