Ground-based monitoring of stratospheric ozone and temperature over
Germany since the 1960s
Abstract
Routine ground-based measurements of total ozone column (TOC), as well
as ozone profile soundings started in the late 1960s in Germany. The
resulting ozone and temperature records at Hohenpeissenberg and Berlin /
Potsdam / Lindenberg show long-term changes similar to other stations in
Central Europe, and to the changes seen globally. Following the increase
of ozone depleting substances (ODS), stratospheric ozone has declined
from the 1960s until the 1990s. Since about 2000, ozone has leveled or
slightly increased, consistent with declining amounts of ODS. The
stratosphere has been cooling and the troposphere has been warming, in
agreement with general expectations due to increasing greenhouse gas
concentrations.
The clearest signs of recovering ozone are seen around 40 km altitude.
Two factors contribute to this increase: the decrease of stratospheric
chlorine loading and cooling of the upper stratosphere, which slows
gas-phase ozone destruction cycles, and enhances the ter-molecular
reaction producing ozone. Tropospheric ozone has increased substantially
from the 1960s to the early 1990s. Since then, it has remained more or
less constant, on a level higher compared to the 1960s and 1970s.
Particularly low tropospheric ozone was observed in 2020, due to reduced
precursor emissions during the COVID-19 related lockdowns.
The atmospheric concentrations of greenhouse gases will likely continue
to rise, while the concentrations of ozone depleting substances are
expected to slowly decline. To see how the atmosphere responds, and to
help understand future changes, continued monitoring will be required
for many years to come, both over Germany and worldwide.