Increasing greenhouse gas concentrations are expected to enhance
the interannual variability of summer climate in Europe and
other mid-latitude regions, potentially causing more frequent
heatwaves. Climate models consistently predict an increase in
the variability of summer temperatures in these areas, but the
underlying mechanisms responsible for this increase remain
uncertain. Here we explore these mechanisms using regional
simulations of recent and future climatic conditions with and
without land–atmosphere interactions. Our results indicate that
the increase in summer temperature variability predicted in
central and eastern Europe is mainly due to feedbacks between
the land surface and the atmosphere. Furthermore, they suggest
that land–atmosphere interactions increase climate variability in
this region because climatic regimes in Europe shift northwards in
response to increasing greenhouse gas concentrations, creating a
new transitional climate zone with strong land–atmosphere coupling
in central and eastern Europe. These findings emphasize the
importance of soil-moisture–temperature feedbacks (in addition
to soil-moisture–precipitation feedbacks) in influencing summer
climate variability and the potential migration of climate
zones with strong land–atmosphere coupling as a consequence
of global warming. This highlights the crucial role of land–
atmosphere interactions in future climate change.

Full Article: http://iacweb.ethz.ch/staff/sonia/

Last Updated: 2006-09-22