Cooling of the Arctic and Antarctic polar stratospheres due to ozone depletion

Abstract

Long time records of stratospheric temperatures indicate that substantial cooling has occurred during spring over polar regions of both hemispheres. These cooling patterns are coincident with observed recent ozone depletions. Time series of temperature from radiosonde, satellite, and National Centers for Environmental Prediction reanalysis data are analyzed in order to isolate the space-time structure of the observed temperature changes. The Antarctic data show strong cooling (of order 6-10 K) in the lower stratosphere (∼12-21 km) since approximately 1985. The cooling maximizes in spring (October-December), with small but significant changes extending throughout Southern Hemisphere summer. No Antarctic temperature changes are observed during midwinter. Significant warming is found during spring at the uppermost radiosonde data level (30 mb, ∼24 km). These observed temperature changes are all consistent with model predictions of the radiative response to Antarctic polar ozone depletion. Winter and spring temperatures in Northern Hemisphere polar regions also indicate a strong cooling in the 1990s, and the temperature changes are coherent with observed ozone losses. The overall space-time patterns are similar between both hemispheres, suggesting that the radiative response to ozone depletion is an important component of the Arctic cooling as well.