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Atmospheric dynamics
NH state of the climate

Seasonal evolution of the polar vortex and wave activity over Siberia
Zcap, WAFz midlatitude, and NAO index
Top : Polar cap geopotential (shading, m), and vertical component of Plumb wave activity flux (red/blue contours).
Bottom : daily North Atlantic Oscillation index (NAO, std deviation)

Polar_Vortex_temperature_ncep2_2021

WAFZ100-midlat-sib_ncep2_2021

MHF100-zonmean_ncep2_2021

UBI_ncep2_2021
December-January
February-March
Top left : polar vortex temperature (10 hPa). Red : current year ; Black and envelope : 1981-2010 climatology +/-2 std deviations
Top right : same, but for cumulative upward Plumb wave activity flux at 100 hPa averaged over Siberia
Bottom left : same, but for meridional heat flux at 100 hPa (zonal average)
Bottom right : Ural Blocking Index (normalized index of Z500 averaged over the 10W/80E ; 45/80N domain)
Follow these links for more diagnostics in animations
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