Abstract
From the indices of monthly and annual climatic drought in six regions in southern South America and their associations with seventeen predictors, the probable physical causes of droughts are analyzed. These indices are used in operational climate monitoring and describe the atmospheric temperature and sea surface temperature (SST) near South America. Subtropical anticyclone activity over both coasts of South America is one of the main predictors, together with its interaction with the continental depression and SST at the coast of Brazil. The highest predictability concentrates in November-December-May and the lowest in March, June and August. In the sub regional scale, the main predictors respond to atmospheric pressure anomalies in the Atlantic Ocean for Argentinean Northwest (NOA), SST in the Brazilian coast for Argentinean Northeast (NEA), anticyclonic conditions over the Pacific and Atlantic for the Central West (CO), the latter and their interaction with the continental depression for Humid Pampa (PH), anticyclonic activity over the Pacific for the Patagonia (PAT) and trans cordillera circulation for Central Chile and Comahue (CHI).
Highlights
Atmospheric droughts were studied in the past mostly as regional phenomena by Jagsich (1929, 36), Maher (1973), Caviedes (1973), Gil Olcina and Olcina Cantos (1997), among others
The indices show that Patagonia has the lowest spatial homogeneity for both methodologies
The analysis shows that predictability of drought indices follows a seasonal cycle with peaks in November-December and May and minima in March-JuneAugust
Summary
Atmospheric droughts were studied in the past mostly as regional phenomena by Jagsich (1929, 36), Maher (1973), Caviedes (1973), Gil Olcina and Olcina Cantos (1997), among others. The application of synoptic atmospheric knowledge to describe drought generating perturbations was presented by De Alessandro and Lichtenstein (1996), Bobba and Minetti (2005), while the impact of SST on the perturbations was studied in Argentina by Lucero and Rodriguez (1991), among others Such climate adversities have the greatest impact on regional and national economies because of their geographical extension, intensity and persistence. In the past a great number of indices of atmospheric circulation and SST were defined, and these are currently used in the operations of some Climate Forecast Centers as diagnosis or predictor variables of a given condition Some of these indices are presented in this paper, as well as their relation to the regional drought indices proposed for simultaneous estimates (diagnosis) in order to detect the causes of droughts. From drought indices to predictor variables, were validated with information from NOAA Reanalysis I (Kistler et al, 2001)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
