© Author(s) 2007. This work is licensed under a Creative Commons License. Atmospheric Chemistry and Physics

• Main Authors: P. A. Newman, J. S. Daniel, D. W. Waugh, E. R. Nash
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2007
• Subjects: Tive; Antarc*; Antarctica
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.648.6135; http://www.atmos-chem-phys.net/7/4537/2007/acp-7-4537-2007.pdf

Abstract. Equivalent effective stratospheric chlorine (EESC) is a convenient parameter to quantify the effects of halogens (chlorine and bromine) on ozone depletion in the stratosphere. We show, discuss, and analyze a new formu-lation of EESC that now includes the effects of age-of-air dependent fractional release values and an age-of-air spec-trum. This EESC can be more appropriately applied to var-ious parts of the stratosphere because of this dependence on mean age-of-air. This new formulation provides quantita-tive estimates of EESC that can be directly related to in-organic chlorine and bromine throughout the stratosphere. In this paper, we first provide a detailed description of the EESC calculation. We then use this EESC formulation to es-timate that human-produced ozone depleting substances will recover to 1980 levels in 2041 in the midlatitudes, and 2067 over Antarctica. These recovery dates are based upon the assumption that the international agreements for regulating ozone-depleting substances are adhered to. In addition to recovery dates, we also estimate the uncertainties and pos-sible problems in the estimated times of recovery. The mid-latitude recovery of 2041 has a 95 % confidence uncertainty