Camilla Andersson

We present a long-term (1990-2023) reanalysis of a flux-based metrics describing ozone uptake to vegetation and the associated risk of ozone damage (Phytotoxic Ozone Dose above a flux threshold of Y, PODY). The dataset covers Sweden at 5.5 km × 5.5 km resolution and includes two generic and four specific PODY receptors (POD1gen for deciduous trees, POD1spec for birch and spruce, POD3gen for crops, and POD6spec for potato and wheat). The PODY reanalysis was constructed using the MATCH Sweden System and input meteorology from the Copernicus European Regional Reanalysis system.

PODY, for all receptors, is highest in the south of Sweden and lowest in the Scandinavian mountains. The estimated PODY for birch and spruce are well above the critical levels set by UNECE in practically all of Sweden. For wheat, the critical limits for grain yield and grain weight are exceeded in most of south and central Sweden.

We find no significant trend in PODY in most areas of Sweden, except for central Sweden for generic deciduous trees and birch (negative) and southern Sweden for potato (positive). These changes are, however, likely influenced the introduction of new observation sites in the ozone analyses. Based on the large inter-annual variation of all receptors during the 1990-2023 period we argue that there is little evidence of temporal trends in any of the receptors during the considered period.

To highlight the effects of varying ozone data as input to the PODY calculations we also performed an additional PODY reanalysis using a selection of consistent ozone observations for the period 1990-2013.