Research project IM/RT/23/DORA (Research action IM)
Thanks to the Montreal Protocol and its Adjustments and Amendments to reduce the emissions of ozone depleting substances, stratospheric ozone is expected to slowly recover globally, although the delay of the recovery is still unsure due to the uncertainties associated to climate change. Detecting this recovery is very challenging because of the large natural variability of stratospheric ozone, and the expected small trend (a few percent per decade). In the polar regions, ozone is especially highly impacted by the effective-chlorine levels, which leads to the well-known “ozone hole” problematic. However, the much higher ozone natural variability in the Arctic, due to larger dynamical variability, complicates the observation of the ozone recovery in this region where no evidence of positive ozone trends is observed up to now (WMO 2018).
The DORA project will focus on this detection of ozone recovery in the Arctic by answering the three questions:
- Do we detect an ozone recovery at ground-based Arctic stations? We will perform long-term trend analysis of ground-based measurements operated from the late nineties up to present at seven stations equipped with FTIR (Fourier Transform Infrared) spectrometers and at seven ozone sounding stations. To detect and attribute the stratospheric ozone trends, we will use the multiple linear regression technique involving a set of proxies that represent physical processes influencing the natural ozone variability. In addition, the trends of tropospheric ozone, an important pollutant and greenhouse gas, will be investigated.
- Is the current ground-based network representative for ozone trends in the Arctic? We will use CAMS (Copernicus Atmosphere Monitoring Service) reanalysis, which combines model data with assimilated observations, to study the spatial and temporal representativeness of our network of stations.
- How well are the satellites monitoring ozone trends in the Arctic? We will use our ground-based data to evaluate several current stratospheric and tropospheric ozone data sets from merged satellite records and detect possible drifts or steps in satellite ozone time-series monitoring.
