We have a new paper that is “in press” for publication;
Herman, B., M. Barlage, T.N. Chase, and R.A. Pielke Sr., 2008: Update on a proposed mechanism for the regulation of minimum mid-tropospheric and surface temperatures in the Arctic and Antarctic. J. Geophys. Res.-Atmos., in press
with the abstract
“This paper is an update from our earlier paper to include data through July 2008. In our earlier paper, which included data through 1998, a mechanism which generally limits Arctic minimum 500 mb temperatures to the -40C to -45C range was presented. The current paper is in agreement with those earlier findings and also shows some evidence of later autumn onset dates of the initial appearance of these temperatures, in agreement with the recent reduction of Arctic sea ice cover in the summer and fall. In the southern hemisphere, little change can be seen for the seasonal onset and end of the temperatures reaching -40°C area, while the appearance of temperatures reaching -44°C area seems to show a later onset date beginning about 1998, but this time period is too small to define a clear trend. The limiting of the minimum of these midtropospheric temperatures has important implications for minimum surface temperatures that can occur over land during the Arctic winter.”
This paper updates our earlier papers on this subject
Chase, T.N., B. Herman, R.A. Pielke Sr., X. Zeng, and M. Leuthold, 2002: A proposed mechanism for the regulation of minimum midtropospheric temperatures in the Arctic. J. Geophys. Res., 107(D14), 10.10291/2001JD001425
Tsukernik, M., T.N. Chase, M.C. Serreze, R.G. Barry, R. Pielke Sr., B. Herman, and X. Zeng, 2004: On the regulation of minimum mid-tropospheric temperatures in the Arctic. Geophys. Res. Letts., 31, L06112, doi:10.1029/2003GL018831.
The latest data (animated 500 hPa temperatures with the coldest temperatures highlighted) can be viewed at the excellent University of Arizona website [Thanks to Ben Herman for making this available to all of us!]; see
The monitoring of this climate metric (areal extent of the coldest temperatures at 500 hPa) should be a high priority of the climate community, since it clearly relates closely to climate variability and change at high latititudes, including sea ice trends as discussed yesterday (see).