Atmospheric Chemistry and Physics Discussions Interactive comment on “Extrapolating future

• Main Author: B. Knudsen
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2004
• Subjects: Arctic; Austin
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.534.8819; http://www.cosis.net/copernicus/EGU/acpd/4/S1192/acpd-4-S1192_p.pdf?PHPSESSID=894d28d5e40ae49277eb2eae9cbb6d5a

John Austin has questioned the use of his own data in Figure 6. Although we do not fully agree with this we might omit the Figure in the revised version. The trend calculations stop in 2001 because FU-Berlin data stop there. Including the last years would decrease the PSC trends. However, such a decrease would probably not be significant since it would likely be due to random fluctuations of Arctic tempera-tures. The NCEP trends have not been used in the paper because NCEP PSC areas do not agree with ERA-40 and FU-Berlin areas, which agree with each other, and ERA-40 agrees with radiosonde temperatures (in the winter 1995/96 and 1996/97). The NCEP PSC areas are 21-25 % lower than the FU-Berlin areas in those two winters. John Austin questions the relevance of showing Figure 1. However, compared to the figure shown in Rex et al. (2004) the time period has been extended backwards from 1966 to 1958 and the PSC areas for the ERA-40 reanalysis are shown for validation S1192 purposes. John Austin suggests we show the case for zero temperature change. But since the