In a recent study Renwick and Revell (1999, hereafter RR99) investigated the atmospheric blocking over the South Pacific. They found that the blocking events occur more frequently over the southeast Pacific during El Niño events in austral spring. Their analysis showed that blocking events are associated with large-scale wave trains lying across the South Pacific from Australia to southern South America. RR99 performed numerical experiments with a linearized barotropic model and showed that the

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... tropical convective heating associated with OLR anomalies, presumably generated during El Niño events, can generate similar wave trains. The purpose of the present comment is to provide observational evidence to show that the Rossby wave propagation similar to the one noted by RR99 is in fact stronger and better organized in austral spring than in other seasons. Several recent studies (Marques and Rao 1999, 2000; Renwick 1998; Sinclair 1996; Rutllant and Fuenzalida 1991) have found a new region of blocking in the South Pacific. Blocking in this region has important implications for weather over South America (Marques and Rao 1999). Rutllant and Fuenzalida (1991) noted the connection between the El Niño-Southern Oscillation (ENSO) and blocking over the southeast Pacific. Renwick (1998) found that the frequency of blocking over the southeast Pacific is related to ENSO. Using 25 years of National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) reanalysis data Marques and Rao (2000) found that the blocking frequency over the southeast Pacific has a negative correlation with the Southern Oscillation index during the austral spring, indicating a higher incidence of blocking during El Niño events. We used monthly mean values of geopotential height for the period 1950-98 to obtain anomalies (observed minus mean) for the El Niño and La Niña events. Geopotential height data at several pressure levels were obtained from NCEP-NCAR reanalysis (Kalnay et al.