scholarly journals Global Distribution and 14-Year Changes in Erythemal Irradiance, UV Atmospheric Transmission, and Total Column Ozone 2005–2018 Estimated from OMI and EPIC Observations

2019 ◽  
Author(s):  
Jay Herman ◽  
Alexander Cede ◽  
Liang Huang ◽  
Jerald Ziemke ◽  
Matthew Kowalewski ◽  
...  

Abstract. Satellite data from the Ozone Measuring Instrument (OMI) and Earth Polychromatic Imaging Camera (EPIC) for ozone amount and scene reflectivity (mostly from clouds) are used to study changes and global distribution of UV erythemal irradiance in mW/m2 E(ζ,ϕ,z,t) and UV index (E/25 mWm2) over the Earth's surface as a function of latitude ζ, longitude ϕ, altitude z, and time t. OMI time series data starting in January 2005 to December 2018 are used to estimate 14-year changes in total column ozone TCO3 and scene reflectivity at 105 specific land plus 77 ocean locations in the Northern and Southern Hemispheres. Estimates of changes in atmospheric transmission T(ζ,ϕ,z,t) derived from cloud and haze reflectivity show almost no average 14-year change from 55° S to 35° N but show an increase from 40° N to 60° N. This implies increased solar insolation at high northern latitudes that suggests positive feedback for global warming. TCO3 has increased at a rate of 2 % per decade for the latitudes between 60° S to 10° N changing to a decrease of 1 % per decade between 40° N to 60° N. The result is an average decrease in E(ζ,ϕ,z,t) at a rate of 2 % per decade in the Southern Hemisphere and an increase between 40° N to 60° N. For some specific sites (latitudes from 55° S to 45° N) there has been little or no change in E(ζ,ϕ,z,t) for the period 2005–2018. Nearly half the sites show the effects of both short- and long-term cloud change as well as total column ozone change. Synoptic EPIC data from the sunlit Earth are used derive ozone and reflectivity needed for global images of the distribution of E(ζ,ϕ,z,t) from sunrise to sunset centered on the Americas, Europe-Africa, and Asia. EPIC data are used to show the latitudinal distribution of E(ζ,ϕ,z,t) from the equator to 75° for specific longitudes. Dangerously high amounts of erythemal irradiance (12 

2020 ◽  
Vol 20 (14) ◽  
pp. 8351-8380
Author(s):  
Jay Herman ◽  
Alexander Cede ◽  
Liang Huang ◽  
Jerald Ziemke ◽  
Omar Torres ◽  
...  

Abstract. Satellite data from the Ozone Measuring Instrument (OMI) and Earth Polychromatic Imaging Camera (EPIC) are used to study long-term changes and global distribution of UV erythemal irradiance E(ζ,φ,z,t) (mW m−2) and the dimensionless UV index E ∕ (25 m Wm−2) over major cities as a function of latitude ζ, longitude φ, altitude z, and time t. Extremely high amounts of erythemal irradiance (12 < UV index <18) are found for many low-latitude and high-altitude sites (e.g., San Pedro, Chile, 2.45 km; La Paz, Bolivia, 3.78 km). Lower UV indices at some equatorial or high-altitude sites (e.g., Quito, Ecuador) occur because of persistent cloud effects. High UVI levels (UVI > 6) are also found at most mid-latitude sites during the summer months for clear-sky days. OMI time-series data starting in January 2005 to December 2018 are used to estimate 14-year changes in erythemal irradiance ΔE, total column ozone ΔTCO3, cloud and haze transmission ΔCT derived from scene reflectivity LER, and reduced transmission from absorbing aerosols ΔCA derived from absorbing aerosol optical depth τA for 191 specific cities in the Northern Hemisphere and Southern Hemisphere from 60∘ S to 60∘ N using publicly available OMI data. A list of the sites showing changes at the 1 standard deviation level 1σ is provided. For many specific sites there has been little or no change in E(ζ,φ,z,t) for the period 2005–2018. When the sites are averaged over 15∘ of latitude, there are strong correlation effects of both short- and long-term cloud and absorbing aerosol change as well as anticorrelation with total column ozone change ΔTCO3. Estimates of changes in atmospheric transmission ΔCT (ζ, φ, z, t) derived from OMI-measured cloud and haze reflectivity LER and averaged over 15∘ of latitude show an increase of 1.1±1.2 % per decade between 60 and 45∘ S, almost no average 14-year change of 0.03±0.5 % per decade from 55∘ S to 30∘ N, local increases and decreases from 20 to 30∘ N, and an increase of 1±0.9 % per decade from 35 to 60∘ N. The largest changes in E(ζ,φ,z,t) are driven by changes in cloud transmission CT. Synoptic EPIC radiance data from the sunlit Earth are used to derive ozone and reflectivity needed for global images of the distribution of E(ζ,φ,z,t) from sunrise to sunset centered on the Americas, Europe–Africa, and Asia. EPIC data are used to show the latitudinal distribution of E(ζ,φ,z,t) from the Equator to 75∘ for specific longitudes. EPIC UV erythemal images show the dominating effect of solar zenith angle (SZA), the strong increase in E with altitude, and the decreases caused by cloud cover. The nearly cloud-free images of E(ζ,φ,z,t) over Australia during the summer (December) show regions of extremely high UVI (14–16) covering large parts of the continent. Zonal averages show a maximum of UVI = 14 in the equatorial region seasonally following latitudes where SZA = 0∘. Dangerously high amounts of erythemal irradiance (12 < UV index < 18) are found for many low-latitude and high-altitude sites. High levels of UVI are known to lead to health problems (skin cancer and eye cataracts) with extended unprotected exposure, as shown in the extensive health statistics maintained by the Australian Institute of Health and Welfare and the United States National Institute of Health National Cancer Institute.


2015 ◽  
Vol 8 (10) ◽  
pp. 4487-4505 ◽  
Author(s):  
K.-L. Chang ◽  
S. Guillas ◽  
V. E. Fioletov

Abstract. Total column ozone variations estimated using ground-based stations provide important independent source of information in addition to satellite-based estimates. This estimation has been vigorously challenged by data inhomogeneity in time and by the irregularity of the spatial distribution of stations, as well as by interruptions in observation records. Furthermore, some stations have calibration issues and thus observations may drift. In this paper we compare the spatial interpolation of ozone levels using the novel stochastic partial differential equation (SPDE) approach with the covariance-based kriging. We show how these new spatial predictions are more accurate, less uncertain and more robust. We construct long-term zonal means to investigate the robustness against the absence of measurements at some stations as well as instruments drifts. We conclude that time series analyzes can benefit from the SPDE approach compared to the covariance-based kriging when stations are missing, but the positive impact of the technique is less pronounced in the case of drifts.


2008 ◽  
Vol 136 (11-12) ◽  
pp. 640-643 ◽  
Author(s):  
Milorad Letic

INTRODUCTION UV Index is an indicator of human exposure to solar ultraviolet (UV) rays. The numerical values of the UV Index range from 1-11 and above. There are three levels of protection against UV radiation; low values of the UV Index - protection is not required, medium values of the UV Index - protection is recommended and high values of the UV Index - protection is obligatory. The value of the UV Index primarily depends on the elevation of the sun and total ozone column. OBJECTIVE The aim of the study is to determine the intervals of possible maximal annual values of the UV Index in Serbia in order to determine the necessary level of protection in a simple manner. METHOD For maximal and minimal expected values of total column ozone and for maximal elevation of the sun, the value of the UV Index was determined for each month in the Northern and Southern parts of Serbia. These values were compared with the forecast of the UV Index. RESULTS Maximal clear sky values of the UV Index in Serbia for altitudes up to 500m in May, June, July and August can be 9 or even 10, and not less than 5 or 6. During November, December, January and February the UV Index can be 4 at most. During March, April, September and October the expected values of the UV Index are maximally 7 and not less than 3. The forecast of the UV Index is within these limits in 98% of comparisons. CONCLUSION The described method of determination of possible UV Index values showed a high agreement with forecasts. The obtained results can be used for general recommendations in the protection against UV radiation.


Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
María Cazorla ◽  
René Parra ◽  
Edgar Herrera ◽  
Francisco Raimundo da Silva

In this study, we characterize atmospheric ozone over the tropical Andes in the boundary layer, the free troposphere, and the stratosphere; we quantify each contribution to total column ozone, and we evaluate the performance of the multi-sensor reanalysis (MSR2) in the region. Thus, we present data taken in Ecuador and Peru (2014–2019). The contribution from the surface was determined by integrating ozone concentrations measured in Quito and Cuenca (Ecuador) up to boundary layer height. In addition, tropospheric and stratospheric column ozone were quantified from ozone soundings (38) launched from Quito during the study time period. Profiles were compared against soundings at Natal (SHADOZ network) for being the closest observational reference with sufficient data in 2014–2019. Data were also compared against stratospheric mixing ratios from the Aura Microwave Limb Sounder (Aura MLS). Findings demonstrate that the stratospheric component of total column ozone over the Andes (225.2 ± 8.9 Dobson Units [DU]) is at similar levels as those observed at Natal (223.3 ± 8.6 DU), and observations are comparable to Aura MLS data. In contrast, the tropospheric contribution is lower over the Andes (20.2 ± 4.3 DU) when compared to Natal (35.4 ± 6.4 DU) due to a less deep and cleaner troposphere. From sounding extrapolation of Quito profiles down to sea level, we determined that altitude deducts about 5–7 DU from the total column, which coincides with a 3%–4% overestimation of the MSR2 over Quito and Marcapomacocha (Peru). In addition, when MSR2 data are compared along a transect that crosses from the Amazon over Quito, the Ecuadorian coast side, and into the Pacific, observations are not significantly different among the three first locations. Results point to coarse reanalysis resolution not being suitable to resolve the formidable altitude transition imposed by the Andes mountain chain. This work advances our knowledge of atmospheric ozone over the study region and provides a robust time series of upper air measurements for future evaluations of satellite and reanalysis products.


2013 ◽  
Vol 6 (6) ◽  
pp. 10081-10115 ◽  
Author(s):  
E. W. Chiou ◽  
P. K. Bhartia ◽  
R. D. McPeters ◽  
D. G. Loyola ◽  
M. Coldewey-Egbers ◽  
...  

Abstract. This paper describes the comparison of the variability of total column ozone inferred from the three independent multi-year data records, namely, (i) SBUV(v8.6) profile total ozone, (ii) GTO(GOME-Type total ozone), and (iii) Ground-based total ozone data records covering the 16-yr overlap period (March 1996 through June 2011). Analyses are conducted based on area weighted zonal means for (0–30° S), (0–30° N), (50–30° S), and (30–60° N). It has been found that on average, the differences in monthly zonal mean total ozone vary between −0.32 to 0.76 % and are well within 1%. For "GTO minus SBUV", the standard deviations and ranges (maximum minus minimum) of the differences regarding monthly zonal mean total ozone vary between 0.58 to 0.66% and 2.83 to 3.82% respectively, depending on the latitude band. The corresponding standard deviations and ranges regarding the differences in monthly zonal mean anomalies show values between 0.40 to 0.59% and 2.19 to 3.53%. The standard deviations and ranges of the differences "Ground-based minus SBUV" regarding both monthly zonal means and anomalies are larger by a factor of 1.4 to 2.9 in comparison to "GTO minus SBUV". The Ground-based zonal means, while show no systematic differences, demonstrate larger scattering of monthly data compared to satellite-based records. The differences in the scattering are significantly reduced if seasonal zonal averages are analyzed. The trends of the differences "GTO minus SBUV" and "Ground-based minus SBUV" are found to vary between −0.04 and 0.12% yr−1 (−0.11 and 0.31 DU yr−1). These negligibly small trends have provided strong evidence that there are no significant time dependent differences among these multi-year total ozone data records. Analyses of the deviations from pre-1980 level indicate that for the overlap period of 1996 to 2010, all three data records show gradual recovery at (30–60° N) from −5% in 1996 to −2% in 2010. The corresponding recovery at (50–30° S) is not as obvious until after 2006.


2013 ◽  
Vol 8 (3) ◽  
pp. 204-209

Results of the total column ozone and ultraviolet (UV-B) erythemally weighted irradiance measurements at the ground-based solar monitoring station at the Kishinev (Moldova) are presented. Diffuse and global components of solar UV-B erythemal irradiance on horizontal plane were continuously measured with sensors UV-S-B-C (of broadband 280-315 nm), Kipp&Zonen. Monthly totals of global and diffuse components of solar UV-B erythemal radiation reveal distinct seasonal variation with respective minimum in winter and maximum in summer. Typical values for these components in limiting cases are presented. A simple polynomial relationship between the global and diffuse components of solar UV-B erythemal radiation measured for cloudless days was derived. It was shown that coefficients of the polynomial depend on daily mean value of aerosol optical thickness (AOT). Collocated measurements of AOT have been carried out with the sunphotometer Cimel CE-318 within the framework of the Aerosol Robotic Network (AERONET) program, managed by NASA/GSFC. Total column ozone content was retrieved from direct solar ultraviolet radiation measurements at 3 discrete wavelengths centered at 305.5, 312.5, and 320 nm within the UV-B range. Ozone measurements were regularly carried out with the hand-held MICROTOPS II Ozonemeter, Solar Light Co. Monthly average values of total column ozone content measured with the MICROTOPS II at the Kishinev are in close agreement with those ones retrieved from the multiyear (1978-2004) database statistics acquired from satellite platforms measurements with the Total Ozone Mapping Spectrometer (TOMS). It was shown the existence of seasonal variability of the total column ozone content with respective minimum values observed at the end of autumn and winter, and maximum values observed at the end of winter and in spring. The maximum and minimum of daily mean values of total column ozone ever measured with TOMS at the satellite platforms overpassed Kishinev site, amounted of ~540 DU (on February 19, 1985) and ~204 DU (on December 1, 1999). Yearly mean value of total column ozone measured at the Kishinev was ~ 338 DU. Total column ozone measurements carried out with MICROTOPS at the Kishinev site from September 2003 to August 2004, gave maximum and minimum values of ozone daily means at ~ 489 DU (on February 12, 2004) and ~259 DU (on December 3, 2003). The estimation of total column ozone trend derived from the TOMS multi-year statistics was ~ -10 DU/decade.


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