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Images, data, and information for the Southern Hemisphere

2000 Antarctic MERRA Wind

Daily progression

The daily progression through the 2000 ozone hole season of the various wind statistics, comparing 2000 to the climatology of all other years. Clicking a link will bring up, in a new window, a PDF vector plot or a plain-text ASCII data file that is suitable for input into any program.

60°S zonal wind

The average east-west (zonal) wind speed for 60°S. This is near the peak of the polar jet maximum. A 45 m s-1wind speed is equal to 100 mph. (Image is shown for 1 April–31 December on the 100-hPa surface.)

45°–75°S zonal wind

The average east-west (zonal) wind speed for 45°S to 75°S. This is near the peak of the polar jet maximum. A 45 m s-1wind speed is equal to 100 mph. (Image is shown for 1 April–31 December on the 100-hPa surface.)

Data description

The Antarctic continent is circled by a strong jet stream in the stratosphere (above 12 km or 39,000 ft). Looking down on the South Pole, this jet stream flows around Antarctica in a clockwise sense. This jet stream isolates air over Antarctica from air in the midlatitudes. The region poleward of this jet stream is called the Antarctic polar vortex. A stronger jet stream flow results in greater isolation of polar air from midlatitude air (less mixing). The air inside the Antarctic polar vortex is also much colder then midlatitude air.

Data source

MERRA is a NASA reanalysis for the satellite era using a major new version of the Goddard Earth Observing System Data Assimilation System Version 5 (GEOS-5). The project focuses on historical analyses of the hydrological cycle in a broad range of weather and climate time scales. It places modern observing systems (such as EOS suite of observations in a climate context. Since these data are from a reanalysis, they are not up-to-date. So, we supplement with the GEOS-5 FP data that are also produced by the GEOS-5 model in near real time. These products are produced by the NASA Global Modeling and Assimilation Office (GMAO).

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