Tham khảo tài liệu 'international perspectives on global environmental change part 15', khoa học tự nhiên, công nghệ sinh học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Strengthening Regional Capacities for Providing Remote Sensing Decision Support in Drylands in the Context of Climate Variability and Change 409 changes including the growth of small farms but also the development of precarious occupation of land which cause the impoverishment of small farmers who have faced increasing difficulty in access to land. These changes have also aggravated the conditions for the social reproduction of this community. In contrast in the northeast of Ceará the agricultural community produces cash crops such as cashew cotton fruits and vegetables involving various irrigation projects along the Jaguaribe River. Total monhtly maize and bean production ton and yields kg ha from 180 municipalities in the entire state of Ceará were the raw data employed as agricultural observations. Total monthly SSTAs utilized as a climate indicator were delimited by the latitudes 170oW-120oW and longitudes 5oS-5oN region and also by the gradient between tropical Atlantic North 5oN-25oN and South Atlantic 5oS-25oS known as the Atlantic Dipole index . Agriculture and climate time series were compiled from digital records. The former are available on the databases of the FUNCEME and the latter were obtained from a file of the Comprehensive Atmospheric Ocean Data Set COADS for the entire period 1971-2000. The COADS file has data of monthly averages in grade points of 1o x 1o latitude-longitude for a period of 1971 to 2000. Total monthly data are averaged from February to April. To assess the behavior of the maize and bean production and yields in response to SSTA fluctuations in the study area the Vulnerability Index VI was designated. To measure how much variation at the same rate and scale the variables in question have deviated from the maximum and minimum values from the long-term record. This index allows a direct comparison among the different variables in question for a given period. It is calculated using the following equation VIj DEVj -DEVmin .
