Compromises between Circumpolar Vortex and Cryospheric Extent

Abstract:

Potential linkages between the circumpolar vortex (CV) and snow/ice cover in both hemispheres are examined for better seasonal and longer-term climate predictions. Long-term (1951~present) maps and statistics of daily/monthly CV size, perimeter and circularity ratio (CR) are produced from the NCEP/NCAR reanalysis 500hPa pressure data sets using Geographic Information System (GIS). Temporal lead/lag correlations of CV variables with circumpolar cryospheric variables including Rutgers University’s Global Snow Lab. Northern Hemisphere snow extent (1967~present) and National Snow & Ice Data Center (NSIDC)’s Arctic/Antarctic Ice Extent (1979~present) data are investigated. Analyses of daily/monthly data show that intra-annual variability of and long-term changes in the CV spatial pattern are associated with those of circumpolar cryospheric covers in both hemispheres. Thermal contrast amplified along their boundaries due to cryospheric albedo feedback may account for these potential linkages. Consistency and dissimilarities at regional scales between circumpolar cryospheric extent and atmospheric circulation will also be discussed in detail.
Key words: circumpolar vortex, cryospheric feedbacks, climate variability and change.