Solar UV radiation measurements in Marambio, Antarctica, during years 2017–2019

Abstract. In March 2017, measurements of downward global irradiance of ultraviolet (UV) radiation were started with a multichannel GUV-2511 radiometer in Marambio, Antarctica (64.23∘ S; 56.62∘ W), by the Finnish Meteorological Institute (FMI) in collaboration with the Servicio Meteorológico Nacional (SMN). These measurements were analysed and the results were compared to previous measurements performed at the same site with the radiometer of the Antarctic NILU-UV network during 2000–2008 and to data from five stations across Antarctica. In 2017/2018 the monthly-average erythemal daily doses from October to January were lower than those averaged over 2000–2008 with differences from 2.3 % to 25.5 %. In 2017/2018 the average daily erythemal dose from September to March was 1.88 kJ m−2, while in 2018/2019 it was 23 % larger (2.37 kJ m−2). Also at several other stations in Antarctica the UV radiation levels in 2017/2018 were below average. The maximum UV indices (UVI) in Marambio were 6.2 and 9.5 in 2017/2018 and 2018/2019, respectively, whereas during years 2000–2008 the maximum was 12. Cloud cover, the strength of the polar vortex and the stratospheric ozone depletion are the primary factors that influence the surface UV radiation levels in Marambio. The lower UV irradiance values in 2017/2018 are explained by the high ozone concentrations in November, February and for a large part of October. The role of cloud cover was clearly seen in December, and to a lesser extent in October and November, when cloud cover qualitatively explains changes which could not be ascribed to changes in total ozone column (TOC). In this study, the roles of aerosols and albedo are of minor influence because the variation of these factors in Marambio was small from one year to the other. The largest variations of UV irradiance occur during spring and early summer when noon solar zenith angle (SZA) is low and the stratospheric ozone concentration is at a minimum (the so-called ozone hole). In 2017/2018, coincident low total ozone column and low cloudiness near solar noon did not occur, and no extreme UV indices were measured.

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Record low ozone values over the Arctic in boreal spring 2020

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-617-2021 ◽

2021 ◽

Vol 21 (2) ◽

pp. 617-633

Author(s):

Martin Dameris ◽

Diego G. Loyola ◽

Matthias Nützel ◽

Melanie Coldewey-Egbers ◽

Christophe Lerot ◽

...

Keyword(s):

Northern Hemisphere ◽

Total Ozone ◽

Stratospheric Ozone ◽

Polar Vortex ◽

Ozone Hole ◽

The Arctic ◽

Atmospheric Conditions ◽

Total Ozone Column ◽

The Antarctic ◽

Ozone Column

Abstract. Ozone data derived from the Tropospheric Monitoring Instrument (TROPOMI) sensor on board the Sentinel-5 Precursor satellite show exceptionally low total ozone columns in the polar region of the Northern Hemisphere (Arctic) in spring 2020. Minimum total ozone column values around or below 220 Dobson units (DU) were seen over the Arctic for 5 weeks in March and early April 2020. Usually the persistence of such low total ozone column values in spring is only observed in the polar Southern Hemisphere (Antarctic) and not over the Arctic. These record low total ozone columns were caused by a particularly strong polar vortex in the stratosphere with a persistent cold stratosphere at higher latitudes, a prerequisite for ozone depletion through heterogeneous chemistry. Based on the ERA5, which is the fifth generation of the European Centre for Medium-Range Weather Forecasts (ECMWF) atmospheric reanalysis, the Northern Hemisphere winter 2019/2020 (from December to March) showed minimum polar cap temperatures consistently below 195 K around 20 km altitude, which enabled enhanced formation of polar stratospheric clouds. The special situation in spring 2020 is compared and discussed in context with two other Northern Hemisphere spring seasons, namely those in 1997 and 2011, which also displayed relatively low total ozone column values. However, during these years, total ozone columns below 220 DU over several consecutive days were not observed in spring. The similarities and differences of the atmospheric conditions of these three events and possible explanations for the observed features are presented and discussed. It becomes apparent that the monthly mean of the minimum total ozone column value for March 2020 (221 DU) was clearly below the respective values found in March 1997 (267 DU) and 2011 (252 DU), which highlights the special evolution of the polar stratospheric ozone layer in the Northern Hemisphere in spring 2020. A comparison with a typical ozone hole over the Antarctic (e.g., in 2016) indicates that although the Arctic spring 2020 situation is remarkable, with total ozone column values around or below 220 DU observed over a considerable area (up to 0.9 million km2), the Antarctic ozone hole shows total ozone columns typically below 150 DU over a much larger area (of the order of 20 million km2). Furthermore, total ozone columns below 220 DU are typically observed over the Antarctic for about 4 months.

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The January 2006 low ozone event over the UK

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-6-8457-2006 ◽

2006 ◽

Vol 6 (5) ◽

pp. 8457-8483 ◽

Cited By ~ 2

Author(s):

M. Keil ◽

D. R. Jackson ◽

M. C. Hort

Keyword(s):

Total Ozone ◽

Stratospheric Ozone ◽

Polar Vortex ◽

British Isles ◽

Stratospheric Polar Vortex ◽

North West ◽

Total Ozone Column ◽

Mixing Ratios ◽

The Uk ◽

Ozone Column

Abstract. A record low total ozone column of 177 DU was observed at Reading, UK, on 19 January 2006. Low ozone values were also recorded at other stations in the British Isles and North West Europe on, and around, this date. Hemispheric maps of total ozone from the World Meteorological Organisation (WMO) Ozone Mapping Centre also show the evolution of this ozone minimum from 15–20 January 2006 over North West Europe. Ozonesonde measurements made at Lerwick, UK, show that ozone mixing ratios in the mid-stratosphere on 18 January are around 1–2 ppmv lower than both climatology and observations made one and two weeks prior to this date. In addition, ozone mixing ratios in the UTLS region were also noticeably reduced on 18 January. Analysis of the ozonesonde observations indicate that the mid-stratosphere ozone accounts for around a third of the reduction in total ozone column measurements while the UTLS ozone values account for two thirds of the depletion. It is evident from the ozonesonde data that ozone loss is occuring at two distinct vertical regions. Met Office analyses indicate that stratospheric polar vortex temperatures were cold enough for Polar Stratospheric Cloud (PSC) formation during 14 days in January prior to the low ozone event on 19 January. The presence of PSCs is confirmed by observations from the Scanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY). As a consequence of a stratospheric sudden warming that was in progress during January 2006, the polar vortex was shifted southwards over northwest Europe. This includes a period from 16 to 19 January where PSCs were present in the vortex over the UK. Throughout most of January suitable conditions were present for ozone destruction by heterogenous chemistry within the polar vortex. Evidence from Lerwick and Sodankylä ozonesonde profiles, and maps of Ertel's potential vorticity calculated from Met Office analyses, strongly suggests that the air inside the stratospheric vortex was poor in ozone for at least one week prior to 18 January. It is also possible that local chemical destruction of stratospheric ozone further contributed to the record low ozone observed at Reading. A closer examination of the WMO total ozone maps shows that the daily minima are often of synoptic, rather than planetary, scale. This therefore suggests a tropospheric, rather than stratospheric, mechanism for the ozone minima. Moderate total ozone depletion is commonly observed in the northern hemisphere middle and high latitude winter. This depletion is related to the lifting of the tropopause associated with the presence of an upper troposphere/lower stratosphere anticyclone. We show a strong link between the ozone minima in the WMO maps and 100 hPa geopotential height from Met Office analyses, and therefore it appears that this may also be a plausible mechanism for the record low ozone column that is observed. Back trajectories calculated by the Met Office NAME III model show that air parcels in the mid-stratosphere do arrive over the British Isles on 19 January via the polar vortex. The NAME III model results also show that air parcels near the tropopause arrive from low latitudes and are transported anticyclonically. Therefore this strongly suggests that the record low ozone values are due to a combination of a raised tropopause and the presence of low ozone stratospheric air aloft.

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Reconstruction and analysis of erythemal UV radiation time series from Hradec Králové (Czech Republic) over the past 50 years

10.5194/acp-2017-701 ◽

2017 ◽

Author(s):

Klára Čížková ◽

Kamil Láska ◽

Ladislav Metelka ◽

Martin Staněk

Keyword(s):

Time Series ◽

Czech Republic ◽

Uv Radiation ◽

Total Ozone ◽

Cloud Cover ◽

Radiation Doses ◽

Total Ozone Column ◽

Ozone Column ◽

Radiation Time ◽

Very High

Abstract. This paper evaluates the variability of erythemal ultraviolet (EUV) radiation from Hradec Králové (Czech Republic) in the period 1964–2013. The EUV radiation time series was reconstructed using a radiative transfer model and additional empirical relationships with the root mean square error of 9.9 %. The reconstructed time series documented the increase in EUV radiation doses in the 1980s and the 1990s (up to 15 % per decade), which is linked to the steep decline in total ozone (10 % per decade). The changes of cloud cover were the major factor affecting the EUV radiation doses especially in the 1960s, 1970s, and at the beginning of the new millennium. The mean annual EUV radiation doses in the decade 2004–2013 declined by 5 %. The factors affecting the EUV radiation doses differed also according to the chosen integration period (daily, monthly, and annually): solar zenith angle was the most important for daily doses, cloud cover for their monthly means, and the annual means of EUV radiation doses were most influenced by total ozone column. The number of days with very high EUV radiation doses increased by 22 % per decade, the increase was statistically significant in all seasons except autumn. The occurrence of the days with very high EUV doses was influenced mostly by low total ozone column (82 % of days), clear-sky or partly cloudy conditions (74 % of days) and by increased surface albedo (19 % of days). The principal component analysis documented that the occurrence of days with very high EUV radiation doses was much affected by the positive phase of North Atlantic Oscillation with an Azores High promontory reaching over central Europe. In the stratosphere, a strong Arctic circumpolar vortex and also the meridional inflow of ozone-poor air from the south-west were favorable for the occurrence of days with very high EUV radiation doses. This is the first analysis of the relationship between the high EUV radiation doses and macro-scale circulation patterns, and therefore more attention should be given also to other dynamical variables that may affect the solar UV radiation on the Earth surface.

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UV radiation measurements in Marambio, Antarctica during years 2017–2019 in a wider temporal and spatial context

10.5194/acp-2019-896 ◽

2019 ◽

Cited By ~ 1

Author(s):

Margit Aun ◽

Kaisa Lakkala ◽

Ricardo Sanchez ◽

Eija Asmi ◽

Fernando Nollas ◽

...

Keyword(s):

Uv Radiation ◽

Stratospheric Ozone ◽

Polar Vortex ◽

Early Summer ◽

Uv Index ◽

Finnish Meteorological Institute ◽

Time Period ◽

Temporal And Spatial ◽

Radiation Measurements

Abstract. In March 2017, ultraviolet (UV) radiation measurements with a multichannel GUV-2511 radiometer were started in Marambio, Antarctica (64.23º S; 56.62º W), by the Finnish Meteorological Institute (FMI) in collaboration with the Argentinian National Meteorological Service (SMN). These measurements were analysed and the results were compared to previous measurements at the same site with NILU-UV radiometer during 2000–2008 and to data from five stations across Antarctica. Measurements in Marambio showed lower UV radiation levels in 2017/2018 compared to those measured during 2000–2008. Also at several other stations in Antarctica the radiation levels were below average in that period. The maximum UV index (UVI) in Marambio was only 6.2, while, during the time period 2000–2008, the maximum was 12. In 2018/2019, the radiation levels were higher than in the previous year and the maximum UVI recorded in Marambio was 9.5. In Marambio, the largest variation of the UV radiation are during the spring and early summer when the stratospheric ozone concentration is at a minimum (the so-called ozone hole). Beside cloud cover, the strength of the polar vortex and the stratospheric ozone depletion are the primary factors that influence the surface UV radiation levels in Antarctica. As the recovery of the ozone layer is slow, the continuation of the measurements is crucial in order to be able to detect long-term changes in UV levels in Antarctica.

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Reconstruction and analysis of erythemal UV radiation time series from Hradec Králové (Czech Republic) over the past 50 years

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-1805-2018 ◽

2018 ◽

Vol 18 (3) ◽

pp. 1805-1818 ◽

Cited By ~ 6

Author(s):

Klára Čížková ◽

Kamil Láska ◽

Ladislav Metelka ◽

Martin Staněk

Keyword(s):

Time Series ◽

Czech Republic ◽

Uv Radiation ◽

Total Ozone ◽

Cloud Cover ◽

Radiation Doses ◽

Total Ozone Column ◽

Ozone Column ◽

Radiation Time ◽

Very High

Abstract. This paper evaluates the variability of erythemal ultraviolet (EUV) radiation from Hradec Králové (Czech Republic) in the period 1964–2013. The EUV radiation time series was reconstructed using a radiative transfer model and additional empirical relationships, with the final root mean square error of 9.9 %. The reconstructed time series documented the increase in EUV radiation doses in the 1980s and the 1990s (up to 15 % per decade), which was linked to the steep decline in total ozone (10 % per decade). The changes in cloud cover were the major factor affecting the EUV radiation doses especially in the 1960s, 1970s, and at the beginning of the new millennium. The mean annual EUV radiation doses in the decade 2004–2013 declined by 5 %. The factors affecting the EUV radiation doses differed also according to the chosen integration period (daily, monthly, and annually): solar zenith angle was the most important for daily doses, cloud cover, and surface UV albedo for their monthly means, and the annual means of EUV radiation doses were most influenced by total ozone column. The number of days with very high EUV radiation doses increased by 22 % per decade, the increase was statistically significant in all seasons except autumn. The occurrence of the days with very high EUV doses was influenced mostly by low total ozone column (82 % of days), clear-sky or partly cloudy conditions (74 % of days) and by increased surface albedo (19 % of days). The principal component analysis documented that the occurrence of days with very high EUV radiation doses was much affected by the positive phase of North Atlantic Oscillation with an Azores High promontory reaching over central Europe. In the stratosphere, a strong Arctic circumpolar vortex and the meridional inflow of ozone-poor air from the southwest were favorable for the occurrence of days with very high EUV radiation doses. This is the first analysis of the relationship between the high EUV radiation doses and macroscale circulation patterns, and therefore more attention should be given also to other dynamical variables that may affect the solar UV radiation on the Earth surface.

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Seasonal impact of biogenic VSL bromine on the evolution of mid-latitude lowermost stratospheric ozone during the 21<sup>st</sup> century

10.5194/acp-2019-1091 ◽

2020 ◽

Author(s):

Javer A. Barrera ◽

Rafael P. Fernandez ◽

Fernando Iglesias-Suarez ◽

Carlos A. Cuevas ◽

Jean-Francois Lamarque ◽

...

Keyword(s):

21St Century ◽

Total Ozone ◽

Stratospheric Ozone ◽

Polar Regions ◽

Total Ozone Column ◽

Seasonal Impact ◽

The Tropics ◽

The Impact ◽

Ozone Column ◽

Modelling Study

Abstract. Biogenic very short-lived bromine (VSLBr) represents, nowadays, ~ 25 % of the total stratospheric bromine loading. Owing to their much shorter lifetime compared to anthropogenic long-lived bromine (LLBr, e.g., halons) and chlorine (LLCl, e.g., chlorofluorocarbons) substances, the impact of VSLBr on ozone peaks at the extratropical lowermost stratosphere, a key climatic and radiative atmospheric region. Here we present a modelling study of the evolution of stratospheric ozone and its chemical losses in extra-polar regions during the 21st century, under two different scenarios: considering and neglecting the additional stratospheric injection of 5 ppt biogenic VSLBr naturally released from the ocean. Our analysis shows that the inclusion of VSLBr result in a realistic stratospheric bromine loading and improves the quantitative 1980–2015 model-satellite agreement of total ozone column (TOC) in the mid-latitudes. We show that the overall ozone response to VSLBr within the mid-latitudes follows the stratospheric abundances evolution of long-lived inorganic chlorine and bromine throughout the 21st century. Additional ozone losses due to VSLBr are maximised during the present-day period (1990–2010), with TOC differences of −8 DU (−3 %) and −5.5 DU (−2 %) for the southern (SH-ML) and northern (NH-ML) mid-latitudes, respectively. Moreover, the projected TOC differences at the end of the 21st century are at least half of the values found for the present-day period. In the tropics, a small (

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Observations of UV radiation and total ozone column using ground based instruments in Río Gallegos, Argentina (51° 36' S, 69° 19' W)

10.1063/1.4804782 ◽

2013 ◽

Cited By ~ 1

Author(s):

Jacobo Salvador ◽

Elian Wolfram ◽

Facundo Orte ◽

Raul D'Elia ◽

Daniela Bulnes ◽

...

Keyword(s):

Uv Radiation ◽

Total Ozone ◽

Total Ozone Column ◽

Ozone Column

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The influence of polar vortex ozone depletion on NH mid-latitude ozone trends in spring

Atmospheric Chemistry and Physics ◽

10.5194/acp-6-2837-2006 ◽

2006 ◽

Vol 6 (10) ◽

pp. 2837-2845 ◽

Cited By ~ 10

Author(s):

S. B. Andersen ◽

B. M. Knudsen

Keyword(s):

Lower Limit ◽

Ozone Depletion ◽

Total Ozone ◽

Polar Vortex ◽

Major Fraction ◽

Total Ozone Column ◽

Trajectory Calculations ◽

Ozone Trends ◽

Decadal Variations ◽

Ozone Column

Abstract. Reverse domain-filling trajectory calculations have been performed for the years 1993, 1995, 1996, 1997, and 2000 to calculate the spreading of ozone depleted air from the polar vortex to midlatitudes in spring. We find that for these years with massive Arctic ozone depletion the zonal mean total ozone column at midlatitudes is reduced with between 7 and 12 DU in the April-May period. The polar vortex and remnants have preferred locations which leads to longitudinal differences in the midlatitude ozone trends. Together with decadal variations in circulation the dilution of ozone depleted air may explain the major fraction of longitudinal differences in midlatitude ozone trends. For the period 1979–1997 the dilution may explain 50% of the longitudinal differences in ozone trends and for the period 1979–2002 it may explain 45%. The dilution also has a significant impact on the zonal mean ozone trends in the April-May period. Although uncertainties are large due to uncertainties in the ozone depletion values and neglect of ozone depletion in other years than 1993, 1995, 1996, 1997, and 2000 we have tried to calculate the size of this effect. We estimate that dilution may explain 29% of the trend in the period 1979–1997 and 33% of the trend in the period 1979–2002 as a lower limit.

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ESTUDIO DE LA INFLUENCIA DE LAS NUBES SOBRE LA RADIACIÓN UV EN LA CIUDAD DE RÍO GALLEGOS, ARGENTINA. STUDY OF THE CLOUD INFLUENCE ON THE UV RADIATION IN RIO GALLEGOS, ARGENTINA

Anales AFA ◽

10.31527/analesafa.2010.21.266 ◽

2010 ◽

pp. 266-271

Author(s):

P. F. Orte ◽

E. Wolfram ◽

J. Salvador ◽

R. D’Elia ◽

C. Marinelli ◽

...

Keyword(s):

Uv Radiation ◽

Optical Thickness ◽

Total Ozone ◽

Ozone Layer ◽

Ozone Hole ◽

Ultraviolet Rays ◽

Uv Index ◽

Total Ozone Column ◽

Cloud Optical Thickness ◽

Ozone Column

The ozone layer is regarded as an invisible filter that protects all life from the dangerous overexposure to ultraviolet rays. The thinning of the ozone layer over the South Pole stratosphere of our planet is a seasonal phenomenon that takes place every year during the spring since the 80s and is known as the “ozone hole”. It is developed on the Antarctic, reaching an area of 30 million square kilometers approximately. In the spring begins to deform reached lower latitudes, presenting specific cases of low total ozone column over Rio Gallegos (51 ° 36 'S, 69 º 19' W) due to the passage of the hole and its border over this city, which can derive in UV indices greater increasing the UV radiation impact on surface. This study evaluates the statistical dependence of the UV index with total ozone column and cloud optical thickness in the Patagonian city of Rio Gallegos for spring and summer. Another aim is to quantify the attenuation of UV radiation produced for the clouds to cases that the ozone hole is passing over the city. The cloud optical thickness and UV index data analyzed were obtained at Station CEILAP RG (CITEFA-CONICET) with a narrowband multichannel radiometer GUV-541 (Biospherical Inc.), and the total ozone column data were extracted from the Satellite OMI / AURA database of NASA. All these belong to the spring and summer seasons of the October 2005-December 2008 period. It is noted that 25% of ozone hole cases in springtime, which would result in a high UVI on Rio Gallegos, are strongly attenuated by the clouds.

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First description and classification of the ozone hole over the Arctic in boreal spring 2020

10.5194/acp-2020-746 ◽

2020 ◽

Author(s):

Martin Dameris ◽

Diego G. Loyola ◽

Matthias Nützel ◽

Melanie Coldewey-Egbers ◽

Christophe Lerot ◽

...

Keyword(s):

Northern Hemisphere ◽

Total Ozone ◽

Stratospheric Ozone ◽

Ozone Hole ◽

The Arctic ◽

Atmospheric Conditions ◽

Total Ozone Column ◽

Boreal Spring ◽

Ozone Column

Abstract. Ozone data derived from the TROPOMI sensor onboard the Sentinel-5 Precursor satellite are showing an atypical ozone hole feature in the polar region of the Northern hemisphere (Arctic) in spring 2020. A persistent ozone hole pattern with minimum total ozone column values around or below 220 Dobson units (DU) was seen for the first time over the Arctic for about 5 weeks in March and early April 2020. Usually an ozone hole with such low total ozone column values has only been observed in the polar Southern hemisphere (Antarctic) in spring over the last 4 decades, but not over the Arctic. The ozone hole pattern was caused by a particularly stable polar vortex in the stratosphere, enabling a persistent cold stratosphere at higher latitudes, a prerequisite for ozone depletion through heterogeneous chemistry. Based on the ERA5 reanalysis from ECMWF, the Northern winter 2019/2020 (from December to March) showed minimum polar cap temperatures consistently below 195 K around 20 km altitude, which enabled enhanced formation of polar stratospheric clouds. The special situation in spring 2020 is compared and discussed in context with two other ozone hole-like features in spring 1997 and 2011 that were showing comparable dynamical conditions in the stratosphere in combination with low total ozone column values. However, during these years total ozone columns below 220 DU over larger areas and over several consecutive days have not been observed. The similarities and differences of the atmospheric conditions of these three events and possible explanations are presented and discussed. It becomes apparent that the monthly mean of the minimum total ozone column value for March 2020 (i.e. 221 DU) was clearly below the respective values found in March 1997 (i.e. 267 DU) and 2011 (i.e. 252 DU), which emphasizes the noteworthiness of the evolution of the polar stratospheric ozone layer in Northern hemisphere spring 2020. These results provide a first description and classification of the development of the Arctic ozone hole in boreal spring 2020 and highlight its peculiarity.

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