scholarly journals Possible values of UV index in Serbia

2008 ◽  
Vol 136 (11-12) ◽  
pp. 640-643 ◽  
Author(s):  
Milorad Letic
Keyword(s):  
Uv Radiation ◽  
The Sun ◽  
Total Column Ozone ◽  
Uv Index ◽  
Clear Sky ◽  
Expected Values ◽  
June July ◽  
Column Ozone ◽  
Ozone Column

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.

scholarly journals Determination of the need for solar UV radiation protection

2010 ◽  
Vol 138 (11-12) ◽  
pp. 752-754
Author(s):  
Milorad Letic
Keyword(s):  
Immune System ◽  
Radiation Protection ◽  
Uv Radiation ◽  
Radiation Intensity ◽  
The Sun ◽  
Time Intervals ◽  
Uv Index ◽  
Solar Uv ◽  
Consistent Method

Introduction. Effects of ultraviolet radiation on the skin, the eyes and the immune system are well known. The need for UV radiation protection is popularized by the introduction of UV index. Uneven intensity of UV radiation in different regions in different periods of the year and in different times of the day requires that recommendations for UV radiation protection are given for possible UV index values in those regions. Objective. The aim of the study is to establish a simple and consistent method for the determination of the need for UV radiation protection in Serbia where UV radiation intensity can be approximated as uniform. Methods. Possible values of UV index during the year and the sun elevation during the day in periods throughout the year were used for the determination of maximal possible UV index values. These values were compared to UV index forecasts regarding UV radiation protection. Results. Maximal possible values for UV index were used for producing the colour graph. Colours on the graph indicate the need for UV radiation protection. Green - protection is not needed, yellow - protection is needed, red - protection is obligatory. Comparisons with the need for protection based on forecasts showed congruence in 97% of cases. Conclusion. The use of the graph for the determination of the need for UV radiation protection gives nearly the same results as recommendations based on UV index forecasts. The advantages of the graph are that it gives recommendations for the whole year, for the time intervals during the day in every period of the year and for the whole territory of Serbia.

scholarly journals A fully Automated Dobson Sun Spectrophotometer for total column ozone and Umkehr measurements

2020 ◽  
Author(s):  
René Stübi ◽  
Herbert Schill ◽  
Jörg Klausen ◽  
Eliane Maillard Barras ◽  
Alexander Haefele
Keyword(s):  
Global Network ◽  
Automated Control ◽  
Total Column Ozone ◽  
Manual Operation ◽  
Clear Sky ◽  
Technical Details ◽  
Column Ozone ◽  
Sky Conditions ◽  
Ozone Column ◽  
Dobson Spectrophotometer

Abstract. The longest ozone column measurements series are based on the Dobson sun spectrophotometers developed in the 1920s by Prof. G. B. W. Dobson. These ingenious and robustly designed instruments still constitute an important part of the global network presently. However, the Dobson sun spectrophotometer needs manual operation which leads to the discontinuation of its use at many stations. To overcome this problem, MeteoSwiss developed a fully automated version of the Dobson spectrophotometer. The description of the data acquisition and automated control of the instrument is presented here with some technical details. The results of different tests performed regularly to control the instrument good working operation are illustrated and discussed. Compared to manual operation, the automation results in higher frequency measurements with lower random error and additional housekeeping information to characterise the measuring conditions. The automated Dobson instrument allows a continuous observation of the ozone column with a resolution of ~1 DU unit under clear sky conditions.

scholarly journals A fully automated Dobson sun spectrophotometer for total column ozone and Umkehr measurements

2021 ◽  
Vol 14 (8) ◽  
pp. 5757-5769
Author(s):  
René Stübi ◽  
Herbert Schill ◽  
Jörg Klausen ◽  
Eliane Maillard Barras ◽  
Alexander Haefele
Keyword(s):  
Global Network ◽  
Automated Control ◽  
Total Column Ozone ◽  
Manual Operation ◽  
Clear Sky ◽  
Technical Details ◽  
Column Ozone ◽  
Sky Conditions ◽  
Ozone Column

Abstract. The longest ozone column measurement series are based on the Dobson sun spectrophotometers developed in the 1920s by Prof. G. B. W. Dobson​​​​​​​. These ingenious and robustly designed instruments still constitute an important part of the global network presently. However, the Dobson sun spectrophotometer requires manual operation, which has led to the discontinuation of its use at many stations, thus disrupting long-term records of observation. To overcome this problem, MeteoSwiss developed a fully automated version of the Dobson spectrophotometer. The description of the data acquisition and automated control of the instrument is presented here with some technical details. The results of different tests performed regularly to assess the instrument's good working conditions are illustrated and discussed. Compared to manual operation, automation results in a higher number of daily measurements with lower random error and additional housekeeping information to characterize the measuring conditions. The automated Dobson instrument allows for continuous observation of the ozone column with a resolution of ∼ 1 DU under clear-sky conditions.

scholarly journals UV Index Forecasting under the Influence of Desert Dust: Evaluation against Surface and Satellite-Retrieved Data

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 96 ◽  
Author(s):  
Dillan Raymond Roshan ◽  
Muammer Koc ◽  
Amir Abdallah ◽  
Luis Martin-Pomares ◽  
Rima Isaifan ◽  
...  
Keyword(s):  
Uv Radiation ◽  
Mesoscale Model ◽  
Dust Storms ◽  
Average Error ◽  
Accurate Estimation ◽  
Strong Impact ◽  
Uv Index ◽  
Desert Dust ◽  
Clear Sky ◽  
Uv Irradiance

Human exposure to healthy doses of UV radiation is required for vitamin D synthesis, but exposure to excessive UV irradiance leads to several harmful impacts ranging from premature wrinkles to dangerous skin cancer. However, for countries located in the global dust belt, accurate estimation of the UV irradiance is challenging due to a strong impact of desert dust on incoming solar radiation. In this work, a UV Index forecasting capability is presented, specifically developed for dust-rich environments, that combines the use of ground-based measurements of broadband irradiances UVA (320–400 nm) and UVB (280–315 nm), NASA OMI Aura satellite-retrieved data and the meteorology-chemistry mesoscale model WRF-Chem. The forecasting ability of the model is evaluated for clear sky days as well as during the influence of dust storms in Doha, Qatar. The contribution of UV radiation to the total incoming global horizontal irradiance (GHI) ranges between 5% and 7% for UVA and 0.1% and 0.22% for UVB. The UVI forecasting performance of the model is quite encouraging with an absolute average error of less than 6% and a correlation coefficient of 0.93. In agreement with observations, the model predicts that the UV Index at local noontime can drop from 10–11 on clear sky days to approximately 6–7 during typical dusty conditions in the Arabian Peninsula—an effect similar to the presence of extensive cloud cover.

scholarly journals Uncertainty analysis of total ozone derived from direct solar irradiance spectra in the presence of unknown spectral deviations

2018 ◽  
Vol 11 (6) ◽  
pp. 3595-3610 ◽  
Author(s):  
Anna Vaskuri ◽  
Petri Kärhä ◽  
Luca Egli ◽  
Julian Gröbner ◽  
Erkki Ikonen
Keyword(s):  
Solar Irradiance ◽  
Total Ozone ◽  
Monte Carlo Model ◽  
Spectral Irradiance ◽  
Total Column Ozone ◽  
Column Ozone ◽  
Ozone Column ◽  
Total Column ◽  
Local Noon ◽  
Good Agreement

Abstract. We demonstrate the use of a Monte Carlo model to estimate the uncertainties in total ozone column (TOC) derived from ground-based direct solar spectral irradiance measurements. The model estimates the effects of possible systematic spectral deviations in the solar irradiance spectra on the uncertainties in retrieved TOC. The model is tested with spectral data measured with three different spectroradiometers at an intercomparison campaign of the research project “Traceability for atmospheric total column ozone” at Izaña, Tenerife on 17 September 2016. The TOC values derived at local noon have expanded uncertainties of 1.3 % (3.6 DU) for a high-end scanning spectroradiometer, 1.5 % (4.4 DU) for a high-end array spectroradiometer, and 4.7 % (13.3 DU) for a roughly adopted instrument based on commercially available components and an array spectroradiometer when correlations are taken into account. When neglecting the effects of systematic spectral deviations, the uncertainties reduce by a factor of 3. The TOC results of all devices have good agreement with each other, within the uncertainties, and with the reference values of the order of 282 DU during the analysed day, measured with Brewer spectrophotometer #183.

scholarly journals Retrieval of ozone column content from airborne Sun photometer measurements during SOLVE II: comparison with coincident satellite and aircraft measurements

2005 ◽  
Vol 5 (8) ◽  
pp. 2035-2054 ◽  
Author(s):  
J. M. Livingston ◽  
B. Schmid ◽  
P. B. Russell ◽  
J. A. Eilers ◽  
R. W. Kolyer ◽  
...  
Keyword(s):  
Research Center ◽  
Total Column Ozone ◽  
Solar Occultation ◽  
Latitudinal Transect ◽  
Validation Experiment ◽  
Satellite Sensors ◽  
Langley Research Center ◽  
Column Ozone ◽  
Ozone Column ◽  
Total Column

Abstract. During the 2003 SAGE (Stratospheric Aerosol and Gas Experiment) III Ozone Loss and Validation Experiment (SOLVE) II, the fourteen-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) was mounted on the NASA DC-8 aircraft and measured spectra of total and aerosol optical depth (TOD and AOD) during the sunlit portions of eight science flights. Values of ozone column content above the aircraft have been derived from the AATS-14 measurements by using a linear least squares method that exploits the differential ozone absorption in the seven AATS-14 channels located within the Chappuis band. We compare AATS-14 columnar ozone retrievals with temporally and spatially near-coincident measurements acquired by the SAGE III and the Polar Ozone and Aerosol Measurement (POAM) III satellite sensors during four solar occultation events observed by each satellite. RMS differences are 19 DU (7% of the AATS value) for AATS-SAGE and 10 DU (3% of the AATS value) for AATS-POAM. In these checks of consistency between AATS-14 and SAGE III or POAM III ozone results, the AATS-14 analyses use airmass factors derived from the relative vertical profiles of ozone and aerosol extinction obtained by SAGE III or POAM III. We also compare AATS-14 ozone retrievals for measurements obtained during three DC-8 flights that included extended horizontal transects with total column ozone data acquired by the Total Ozone Mapping Spectrometer (TOMS) and the Global Ozone Monitoring Experiment (GOME) satellite sensors. To enable these comparisons, the amount of ozone in the column below the aircraft is estimated either by assuming a climatological model or by combining SAGE and/or POAM data with high resolution in-situ ozone measurements acquired by the NASA Langley Research Center chemiluminescent ozone sensor, FASTOZ, during the aircraft vertical profile at the start or end of each flight. Resultant total column ozone values agree with corresponding TOMS and GOME measurements to within 10-15 DU (~3%) for AATS data acquired during two flights - a longitudinal transect from Sweden to Greenland on 21 January, and a latitudinal transect from 47° N to 35° N on 6 February. For the round trip DC-8 latitudinal transect between 34° N and 22° N on 19-20 December 2002, resultant AATS-14 ozone retrievals plus below-aircraft ozone estimates yield a latitudinal gradient that is similar in shape to that observed by TOMS and GOME, but resultant AATS values exceed the corresponding satellite values by up to 30 DU at certain latitudes. These differences are unexplained, but they are attributed to spatial and temporal variability that was associated with the dynamics near the subtropical jet but was unresolved by the satellite sensors. For selected cases, we also compare AATS-14 ozone retrievals with values derived from coincident measurements by the other two DC-8 based solar occultation instruments: the National Center for Atmospheric Research Direct beam Irradiance Airborne Spectrometer (DIAS) and the NASA Langley Research Center Gas and Aerosol Monitoring System (GAMS). AATS and DIAS retrievals agree to within RMS differences of 1% of the AATS values for the 21 January and 19-20 December flights, and 2.3% for the 6 February flight. Corresponding AATS-GAMS RMS differences are ~1.5% for the 21 January flight; GAMS data were not compared for the 6 February flight and were not available for the 19-20 December flight. Line of sight ozone retrievals from coincident measurements obtained by the three DC-8 solar occultation instruments during the SAGE III solar occultation event on 24 January yield RMS differences of 2.1% for AATS-DIAS and 0.5% for AATS-GAMS.

scholarly journals Monte Carlo method for determining uncertainty of total ozone derived from direct solar irradiance spectra: Application to Izaña results

2018 ◽  
Author(s):  
Anna Vaskuri ◽  
Petri Kärhä ◽  
Luca Egli ◽  
Julian Gröbner ◽  
Erkki Ikonen
Keyword(s):  
Monte Carlo ◽  
Total Ozone ◽  
Monte Carlo Model ◽  
Spectral Irradiance ◽  
Total Column Ozone ◽  
Solar Spectral Irradiance ◽  
Irradiance Data ◽  
Column Ozone ◽  
Ozone Column ◽  
Total Column

Abstract. We demonstrate a Monte Carlo model to calculate the uncertainties of total ozone column, TOC, derived from ground-based directional solar spectral irradiance measurements. The model takes into account effects that correlations in the spectral irradiance data may have on the results. The model is tested with spectral data measured with three different spectroradiometers at an intercomparison campaign of the research project Traceability for atmospheric total column ozone at Izaña, Tenerife on 17 September 2016. The TOC values derived at noon have expanded uncertainties of 1.3 % for a high-end scanning spectroradiometer, 1.3 % for a high-end array spectroradiometer, and 3.3 % for a roughly adopted instrument based on commercially available components and an array spectroradiometer. The level of TOC measured with reference Brewer spectrophotometer #183 is of the order of 282 DU during the analysed day and in agreement with the results of the two former instruments.

scholarly journals UV Index and Total Ozone Column Climatology of Nepal Himalaya Using TOMS and OMI Data

2016 ◽  
Vol 9 (1) ◽  
pp. 45-59
Author(s):  
R.R. Sharma ◽  
B. Kjeldstad ◽  
P.J. Espy
Keyword(s):  
High Altitude ◽  
Total Ozone ◽  
Extreme Values ◽  
Nepal Himalaya ◽  
Uv Index ◽  
Total Ozone Column ◽  
Clear Sky ◽  
Ground Measurement ◽  
Filter Radiometer ◽  
Ozone Column

Ultraviolet index (UVI) and Total Ozone Column (TOC) climatology of six stations of Nepal Himalaya using ground measurement, and OMI / TOMS satellite data is presented. The positive bias found in the OMI UV index from previous study is corrected empirically using a ratio factor using the clear sky coincident data of OMI and ground measurement from NILU UV multi-band filter radiometer (MBFR). UV index >3 in the winter months (e.g. December) and more than 9 during the summer months (May-August) are common in most of the stations. High altitude stations even have more extreme values (>11) during the summer months. Under some meteorological conditions, UV index often found more than 16 at the high altitude station (latitude 28o, altitude 2850m) during a clear sky day in the monsoon season. Diurnal and altitudinal variability is also highlighted. Monthly average TOC climatology from November 1978 to March 2012 using TOMS (Nimbus 7, Meteor3 and Earth Probe) and OMI is also presented. The ozone column data follows the annual cycle, minimum in November/December and maximum in April/May. In addition, slight negative trend of TOC is found in the data from 1978 to 2012.Journal of Hydrology and Meteorology, Vol. 9(1) 2015, p.45-59

scholarly journals Global distribution and 14-year changes in erythemal irradiance, UV atmospheric transmission, and total column ozone for2005–2018 estimated from OMI and EPIC observations

2020 ◽  
Vol 20 (14) ◽  
pp. 8351-8380
Author(s):  
Jay Herman ◽  
Alexander Cede ◽  
Liang Huang ◽  
Jerald Ziemke ◽  
Omar Torres ◽  
...  
Keyword(s):  
High Altitude ◽  
Global Distribution ◽  
Series Data ◽  
Atmospheric Transmission ◽  
Low Latitude ◽  
Total Column Ozone ◽  
Uv Index ◽  
Column Ozone ◽  
Total Column

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.

A Clear Sky Model of Diffuse Sky Radiance

1987 ◽  
Vol 109 (1) ◽  
pp. 9-14 ◽  
Author(s):  
F. C. Hooper ◽  
A. P. Brunger ◽  
C. S. Chan
Keyword(s):  
Direct Determination ◽  
Field Of View ◽  
Mean Bias Error ◽  
Bias Error ◽  
Mean Square ◽  
Clear Sky ◽  
Expected Values ◽  
Sky Radiance ◽  
Made In

A model, previously proposed, describing the sky radiance as a continuous function, has been calibrated from 11,000 individual measurements made in scans taken across springtime skies in Toronto using a narrow field of view radiometer. The model reproduces the measured sky radiance with a mean bias error under five percent and a root mean square error only slightly larger than the standard deviation of the measurements. The model is applied to the calculation of the ratio of the clear sky diffuse irradiance on a slope to that on a horizontal surface. Charts are presented for the direct determination of the expected values of these ratios for surfaces at three tilts and at any azimuth.

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