Relación de las anomalías climáticas de la atmósfera libre sobre Costa Rica y la variabilidad de las precipitaciones durante los eventos El Niño
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Date
2001
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Tópicos Meteorológicos y Oceanográficos
Abstract
The main physical causes of the sharp seasonal and inter-annual changes in the two rainfall regimes of Costa Rica during El Niño events are explained by means of the results of Alvarado and Fernández (2001). It is found that the rainfall anomalies are associated with: (i) the persistence of the northerly winds in the lower troposphere and the intensification (weakening) of the easterlies in the summer (winter) period, whose interaction with topography enhances the Föhn effect, (ii) the development of anomalous westerly winds in the upper troposphere during summer, (iii) the sharp decrease of humidity in the lower troposphere and its increase at mid-levels, (iv) the shorter time of permanence over Costa Rica of the ITCZ and its location further South than usual on the Pacific, (v) the considerable increase in wind shear during winter and summer, (vi) the higher values in equivalent potential temperature (qe) and the higher elevation of the convectively unstable layer, which implies a greater potential for deep convection, (vii) the decrease in the tropical cyclone activity in the Caribbean Sea and its increase in the Pacific Ocean, and (viii) the greater convergence in Western Caribbean due to a greater dynamic instability associated to the intensification of the lower level jet.
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Alvarado, L.F. y Fernández, W. (2001). Relación de las anomalías climáticas de la atmósfera libre sobre Costa Rica y la variabilidad de las precipitaciones durante los eventos El Niño. Tópicos Meteorológicos y Oceanográficos, 8(2), 145-157.