Response in tropopause polar vortex characteristics to future reductions in sea ice

Substantial reductions of Arctic sea ice during the summer are leaving increasingly large areas of open water during the autumn and early winter. Greater amounts of heat and moisture have the potential to alter the unique conditions that enable Tropopause Polar Vortices (TPVs) to be maintained over the Arctic by reducing their radiative intensification mechanism. Since TPVs are important dynamical predecessors to surface cyclones, changes in their characteristics due to changing sea ice may be a key to understanding changes to surface low locations and intensity in the future. Here, we present two high-resolution numerically simulated climatologies to examine the impact of reducing sea ice on TPV characteristics and the resulting effects on surface lows. We seek to better understand the relationship between changes in surface weather patterns with changes in the characteristics of TPVs.

Results show that TPV characteristics change substantially in the absence of sea ice. This result is consistent with what is known about the typical habitats of TPVs. In addition to this, the traditional areas of cyclogenesis and cyclolysis shift between the two runs in response to changes in the large scale circulation. Dominate changes in sea level pressure patterns are due to changes in TPV location rather than changes to the locations of baroclinic regions determined from sea ice location. The upper level flow is affected by persistent ridging that develops over the North Atlantic and North Pacific.