ENSO influence on soil water balance and temperature in pampean flatlands (Argentina) with special analysis to San Pedro area

SCARPATI O. E., J. A. FORTE LAY, M. E. FERNANDEZ LONG, , AND A. D. CAPRIOLO

Environmental change and rational water use

Orientación Gráfica

Lugar: Buenos Aires; Año: 2007; p. 169 - 183

In the present paper, air temperature and agro climatic characteristics in pampean flatlands are analyzed with special emphasis to San Pedro area (Buenos Aires province). Soil water balance, autumn surplus, maximum and minimum temperatures were studied with their relationship to ENSO. The values of daily soil water storages were calculated for the period 1967-2005 by soil water balance according to Thornthwaite and Mather method using the daily precipitation and daily normal potential evapotranspiration calculated by the Penman-Monteith formula. ENSO events were separated according to El Niño or warm phase and La Niña or cold phase, with the remaining cases being Neutral condition. The scheme used for determining the ENSO phases was following the Wolter classification by employing terciles of the ranked MEI values. So during the period 1967-2005, there are 14 cases of El Niño, 11 of La Niña and the rest 14 are Neutral. The paper allows a visualisation of ENSO influence over summer soil water storage and autumn soil water surplus. It can be said that El Niño years contribute with higher soil water storage, higher summer and autumn soil water surplus and colder maximum temperature than La Niña years.