Bypass Navigation?

• + NASA
• + Laboratory for Atmospheres
• + Contact NASA

Ozone Hole Meteorology: Ozone

The depth and area of the ozone hole are primarily governed by amounts of chlorine and bromine in the Antarctic stratosphere. Very low temperatures are needed to form polar stratospheric clouds (PSCs). Chlorine gases react on the of these PSCs to release chlorine into a form that can easily destroy ozone. The chlorine and bromine chemical catalytic react destroy ozone need sunlight. Hence, the ozone hole begins to grow as the sun is rising over Antarctica at the end of the winter.

The ozone hole begins to grow in August and reaches its largest area in depth in the middle of September to early October period. In the early years (before 1984) the hole was small because chlorine and bromine levels over Antarctica were low. Year-to-year variations in area and depth are caused by year-to-year variations in temperature. Colder conditions result in a larger area and lower ozone values in the center of the hole.

• Ozone
• Temperature
• Wind
• Potential Vorticity
• Heat Flux

Comparison to all years

The following figures show the daily progression through the ozone hole season, comparing the current year to the climatology of all other years.

Ozone Hole Area	The ozone hole area is determined from total ozone satellite measurements. It is defined to be that region of ozone values below 220 Dobson Units (DU) located south of 40°S. Values below 220 DU represent anthropogenic ozone losses over Antarctica.
Ozone Minimum	The minimum ozone is found from total ozone satellite measurements in the 40–90°S region. No interpolation of missing values is performed. This means that the actual minimum value on a day may be estimated too high, especially in the polar night region.
Ozone Mass Deficit	The ozone mass deficit is determined from total ozone satellite measurements. It combines the effects of changes in area and depth. It is the total amount of mass that is deficit relative to the amount of mass present for a value of 220 Dobson Units (DU).