Long-term trends in the middle atmosphere dynamics at northern middle latitudes – one regime or two different regimes?
Other literature type
(issn: 1680-7324, eissn: 1680-7324)
Due to increasing atmospheric concentration of greenhouse gases and changing
stratospheric ozone concentration, both of anthropogenic origin, various
quantities in the middle atmosphere reveal long-term changes and trends.
Lastovicka and Krizan (2006) indicated possibility of change of trends in
the dynamics in the northern midlatitude middle atmosphere as a whole in the
1990s. To search for such change of trends we use data on winds in the
mesopause region, on total columnar ozone, on ozone laminae, on winds in the
middle and lower stratosphere, and on peak electron density in the E region
of the ionosphere. One group of quantities, the mesopause region wind-like
trends, changes their trends around 1990, the other one, the total
ozone-like trends, in the mid-1990s. Altogether they create a skeleton of
scenario of the change of the middle atmosphere dynamics trends in the
1990s. Drivers of these changes appear to be different for the first group
and for the second group. Tropospheric processes seem to play a role in the
changes of trends in middle atmospheric dynamics.