Observational studies of low-frequency oscillations in the Southern Hemisphere

摘要: A 40-50 day atmospheric oscillation has recently been reported in the southeastern Pacific based on analyses of satellite-derived micro­ wave brightness temperature data. Prior to this, such oscillations have not generally recognized this region. The purpose Note is provide corroboration microwave from an independent data set, four years rawinsonde Easter Island (27®S, 109'W). Significant spectral peaks with period 45-53 days were found zonal wind near jet core (300-200 mb) and underside jet. signal also present 100 mb as shown by strong coherence between 400 tempera­ ture perturbations. Direct comparison pertur­ bations show good agreement. There indication a lower frequency signal, about 6584 period, meridional at 1000 mb. This appears be vertically evanescent maximum amplitude surface.