Effects of Ozone and Clouds on Temporal Variability of Surface UV Radiation and UV Resources over Northern Eurasia Derived from Measurements and Modeling

Abstract

Temporal variability in erythemal radiation over Northern Eurasia (40°–80° N, 10° W–180° E) due to total ozone column (X) and cloudiness was assessed by using retrievals from ERA-Interim reanalysis, TOMS/OMI satellite measurements, and INM-RSHU chemistry–climate model (CCM) for the 1979–2015 period. For clear-sky conditions during spring and summer, consistent trends in erythemal daily doses (Eery) up to +3%/decade, attributed to decreases in X, were calculated from the three datasets. Model experiments suggest that anthropogenic emissions of ozone-depleting substances were the largest contributor to Eery trends, while volcanic aerosol and changes in sea surface temperature also played an important role. For all-sky conditions, Eery trends, calculated from the ERA-Interim and TOMS/OMI data over the territory of Eastern Europe, Siberia and Northeastern Asia, were significantly larger (up to +5–8%/decade) due to a combination of decrease in ozone and cloudiness. In contrast, all-sky maximum trends in Eery, calculated from the CCM results, were only +3–4%/decade. While Eery trends for Northern Eurasia were generally positive, negative trends were observed in July over central Arctic regions due to an increase in cloudiness. Finally, changes in the ultraviolet (UV) resources (characteristics of UV radiation for beneficial (vitamin D production) or adverse (sunburn) effects on human health) were assessed. When defining a “UV optimum” condition with the best balance in Eery for human health, the observed increases in Eery led to a noticeable reduction of the area with UV optimum for skin types 1 and 2, especially in April. In contrast, in central Arctic regions, decreases in Eery in July resulted in a change from “UV excess” to “UV optimum” conditions for skin types 2 and 3.

Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2020

“…Trends in UV radiation were calculated from UV measurements for several European stations (Reading (51° N), Uccle (51° N), Thessaloniki (41° N), and Sodankylä (67° N)) [ 60 ]; Northern Eurasia (a region north of 40° N extending from Scandinavia to Siberia) [ 61 ]; and a site near the equator (Quito, Ecuador, 2,850 m above sea level) [ 62 ]. These new studies generally confirmed the conclusions from our last update assessment [ 1 ], i.e., changes in UV radiation during the last 20 years have been small (generally less than ca .…”

Stratospheric ozone, UV radiation, and climate interactions

“…Trends in erythemal daily doses (D ery ) were calculated for the period 1979–2015 over Northern Eurasia (a region between 40° and 80° N and extending in longitude from Scandinavia to Siberia) using simulations by a climate chemistry model (INM-RSHU 34 ), re-analyses of atmospheric data (ERA-Interim 35 ), and data from satellite measurements (TOMS/OMI) [ 242 ]. For cloud-free conditions, statistically significant increases in D ery of up to 3% per decade were found for spring and summer over large areas and attributed to decreases in TCO.…”

Preface: Ozone Evolution in the Past and Future

“…This finding would be useful to constrain solar forcing magnitude if some reconstructions of the ozone are available. Chubarova et al [9] analyzed the evolution of erythemal radiation over Northern Eurasia caused by total column ozone and cloud amount variabilities, acquired from the observations and model simulations. They found generally positive trends for all months and locations except in the central Arctic in July, which is driven by the increase in cloud amount.…”