Negative storm surges in the port of Buenos Aires

CAMPETELLA, CLAUDIA; D`ONOFRIO ENRIQUE; CERNE, BIBIANA; FIORE, MÓNICA; POSSIA, NORMA

INTERNATIONAL JOURNAL OF CLIMATOLOGY

Wiley InterScience

Año: 2006 vol. 27

0899-8418

Storm surges are water-level anomalies linked to meteorological conditions which interact with astronomical tides. This study presents the first approach to the atmospheric circulation patterns in the Río de la Plata estuary (port of Buenos Aires) that cause negative storm surges (NSS) lower than - 120 cm. The aim of this work is to make a comprehensive statistical analysis of the NSS and to examine their variability on monthly to interdecadal scales. These events occur with a frequency of 4.64 events per year and take place during the whole year but are more usual during the austral winter. They persist from 10 to 50 h and take more time to reach their maximum depth than to recover. The interdecadal variability of all NSS lower than - 120 cm indicates a reduction in the number of cases. However, a detailed analysis shows that the more intense events (lower than - 180 cm) increase not only in their number but in their depth as well. NSS are caused by different atmospheric patterns that promote the generation of west component winds. Observational winds recorded at two synoptic stations suggest that the most frequent wind directions are north, northwest and west at the beginning of the events. Storm surges lower than - 180 cm are related to a cyclone located in the east of Buenos Aires province. This system intensifies and moves towards the southeast, favouring westerly winds over the Río de la Plata. The interdecadal variability analysis of the deepest surges suggests a deepening of the cyclone since 1970. Copyright © 2006 Royal Meteorological Society