scholarly journals UV variability in Moscow according to long-term UV measurements and reconstruction model

2008 ◽  
Vol 8 (1) ◽  
pp. 893-906 ◽  
Author(s):  
N. Y. Chubarova

Abstract. Long-term measurements of erythemally weighted UV irradiance (Qer) have been analyzed for the 1999–2006 period as well as UV variability according to reconstruction model since 1968. The estimates of different atmospheric parameters effects, including NO2 content, on Qer) have been obtained on seasonal and interannual scales. It has been shown that NO2 content in conditions of large megalopolis provides average Qer decrease of about 1.5–2%. The seasonal variations of the observed UV indices are discussed from the point of view of the impact on health. Using the reconstruction model we showed a distinct growth in Qer since 1980 due to decrease in total ozone (+2.5% per decade), effective cloud amount transmission (+2.1% per decade) and aerosol loading (+1.1% per decade). However, there is no changes in Qer over larger 1968–2006 period due to significant decrease in effective cloud amount transmission (−11% per decade) in 1968–1980.

2008 ◽  
Vol 8 (12) ◽  
pp. 3025-3031 ◽  
Author(s):  
N. Y. Chubarova

Abstract. Long-term measurements of erythemally weighted UV irradiance (Qer) have been analyzed for the 1999–2006 period as well as UV variability according to a reconstruction model since 1968. The estimates of different atmospheric parameters effects, including NO2 content, on Qer have been obtained on seasonal and interannual scales. It has been shown that NO2 content in conditions of large megalopolis provides average Qer decrease of about 1.5–2%. The seasonal variations of the observed UV indices are discussed from the point of view of the impact on health. Using the reconstruction model we showed a distinct growth in Qer since 1980 due to changes in total ozone (+2.5% per decade), effective cloud amount transmission (+2.1% per decade) and aerosol loading (+1.1% per decade). However, there is no change in Qer over the longer 1968–2006 period due to significant decrease in effective cloud amount transmission (−11% per decade) in 1968–1980.


2020 ◽  
Vol 4 (1) ◽  
pp. 5
Author(s):  
Elena Volpert ◽  
Natalia Chubarova

The temporal variability of solar shortwave radiation (SSR) has been assessed over northern Eurasia (40°–80° N; 10° W–180° E) by using an SSR reconstruction model since the middle of the 20th century. The reconstruction model estimates the year-to-year SSR variability as a sum of variations in SSR due to changes in aerosol, effective cloud amount and cloud optical thickness, which are the most effective factors affecting SSR. The retrievals of year-to-year SSR variations according to different factors were tested against long-term measurements in the Moscow State University Meteorological Observatory from 1968–2016. The reconstructed changes show a good agreement with measurements with determination factor R2 = 0.8. The analysis of SSR trends since 1979 has detected a significant growth of 2.5% per decade, which may be explained by its increase due to the change in cloud amount (+2.4% per decade) and aerosol optical thickness (+0.4% per decade). The trend due to cloud optical thickness was statistically insignificant. Using the SSR reconstruction model, we obtained the long-term SSR variability due to different factors for the territory of northern Eurasia. The increasing SSR trends have been detected on most sites since 1979. The long-term SSR variability over northern Eurasia is effectively explained by changes in cloud amount and, in addition, by changes in aerosol loading over the polluted regions. The retrievals of the SSR variations showed a good agreement with the changes in global radiance measurements from the World Radiation Data Center (WRDC) archive. The work was supported by RFBR grant number 18-05-00700.


2008 ◽  
Vol 8 (23) ◽  
pp. 7033-7043 ◽  
Author(s):  
S. Simic ◽  
P. Weihs ◽  
A. Vacek ◽  
H. Kromp-Kolb ◽  
M. Fitzka

Abstract. The influence of variability of atmospheric parameters on short- and long-term changes of spectral UV irradiance measured at the Sonnblick observatory (47.03° N, 12.57° E, 3106 m) during the period from 1994 to 2006 is studied. Measurements were performed with the Brewer #093 single-monochromator spectrophotometer and with a Bentham DM 150 spectroradiometer (double-monochromator). The influence of ozone, albedo, snowline and clouds on UV variability is evaluated for each parameter separately using 10-year climatology. It is found that the effect of total ozone on short-term variability of UV irradiance at 305 nm can be more than 200% and on average more than 50%. Clouds can cause variability of 150% or more and on average 35%. Variability caused by albedo reaches a maximum of 32% in April (6% on average). In summer and autumn, total ozone and clouds strongly influence the variability of UV radiation, whereas in winter and spring ozone has the more pronounced effect. A decrease in snowline height from 3000 m to 800 m a.s.l. enhances the UV irradiance by a factor of 1.24 for clear sky conditions and by a factor of 1.7 for 8/8 cloud cover. Long-term trends are investigated for the time period from 1994 to 2006 based on clear-sky measurements, using the non-parametric Mann-Kendall trend test. Significant downward trends (99% confidence level) are found for solar zenith angle 55° at wavelengths from 305 nm to 324 nm and erythemally weighted irradiance according to CIE, which are caused by an increase in sunshine duration during periods of high total column ozone. Significant trends (90% confidence level) were also found for other combinations of wavelength and SZA.


2019 ◽  
Vol 12 (2) ◽  
pp. 987-1011
Author(s):  
Kostas Eleftheratos ◽  
Christos S. Zerefos ◽  
Dimitris S. Balis ◽  
Maria-Elissavet Koukouli ◽  
John Kapsomenakis ◽  
...  

Abstract. In this work we present evidence that quasi-cyclical perturbations in total ozone (quasi-biennial oscillation – QBO, El Niño–Southern Oscillation – ENSO, and North Atlantic Oscillation – NAO) can be used as independent proxies in evaluating Global Ozone Monitoring Experiment (GOME) 2 aboard MetOp A (GOME-2A) satellite total ozone data, using ground-based (GB) measurements, other satellite data, and chemical transport model calculations. The analysis is performed in the frame of the validation strategy on longer time scales within the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Satellite Application Facility on Atmospheric Composition Monitoring (AC SAF) project, covering the period 2007–2016. Comparison of GOME-2A total ozone with ground observations shows mean differences of about -0.7±1.4 % in the tropics (0–30∘), about +0.1±2.1 % in the mid-latitudes (30–60∘), and about +2.5±3.2 % and 0.0±4.3 % over the northern and southern high latitudes (60–80∘), respectively. In general, we find that GOME-2A total ozone data depict the QBO–ENSO–NAO natural fluctuations in concurrence with the co-located solar backscatter ultraviolet radiometer (SBUV), GOME-type Total Ozone Essential Climate Variable (GTO-ECV; composed of total ozone observations from GOME, SCIAMACHY – SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY, GOME-2A, and OMI – ozone monitoring instrument, combined into one homogeneous time series), and ground-based observations. Total ozone from GOME-2A is well correlated with the QBO (highest correlation in the tropics of +0.8) in agreement with SBUV, GTO-ECV, and GB data which also give the highest correlation in the tropics. The differences between deseazonalized GOME-2A and GB total ozone in the tropics are within ±1 %. These differences were tested further as to their correlations with the QBO. The differences had practically no QBO signal, providing an independent test of the stability of the long-term variability of the satellite data. Correlations between GOME-2A total ozone and the Southern Oscillation Index (SOI) were studied over the tropical Pacific Ocean after removing seasonal, QBO, and solar-cycle-related variability. Correlations between ozone and the SOI are on the order of +0.5, consistent with SBUV and GB observations. Differences between GOME-2A and GB measurements at the station of Samoa (American Samoa; 14.25∘ S, 170.6∘ W) are within ±1.9 %. We also studied the impact of the NAO on total ozone in the northern mid-latitudes in winter. We find very good agreement between GOME-2A and GB observations over Canada and Europe as to their NAO-related variability, with mean differences reaching the ±1 % levels. The agreement and small differences which were found between the independently produced total ozone datasets as to the influence of the QBO, ENSO, and NAO show the importance of these climatological proxies as additional tool for monitoring the long-term stability of satellite–ground-truth biases.


2019 ◽  
Vol 34 (1) ◽  
pp. 25-47
Author(s):  
Fabio Bego

This article investigates how some prominent and less known Albanian activists perceived their Southern Slav neighbors at the turn of the twentieth century. The research explores the way in which the spread of nationalism conditioned the positioning of Albanians and Slavs in the process of identity construction and how such identities mirrored their reciprocal political claims. Recent scholarship has often emphasized that the affirmation of national ideas led to the fragmentation of Balkan communities by turning Albanian-speaking populations and their Slavic-speaking neighbors into “others.” My analysis expands this assertion by elaborating a theoretical approach that allows us to explore the impact of nationalism on the post-1878 Balkan context from a more dynamic point of view. National discourses did not only lay the foundation for a differentiation between the Balkan communities, but were also tools for promoting joint political activism. National activists often felt it necessary to cooperate in order to deal with the challenges posed by the surrounding environment, which was common to both Albanians and Slavs. Various contingent circumstances led Albanian activists to project long-term forms of coexistence with their neighbors, and to imagine forms of political, cultural, and social synthesis with the Slavs.


2008 ◽  
Vol 47 (6) ◽  
pp. 1802-1813 ◽  
Author(s):  
Yong-Sang Choi ◽  
Chang-Hoi Ho ◽  
Jinwon Kim ◽  
Dao-Yi Gong ◽  
Rokjin J. Park

Abstract The authors investigate the short-term relationship between aerosol concentrations and summer rainfall frequency in China using the daily surface observations of particulate matters with a diameter of less than 10 μm (PM10) mass concentration, rainfall, and satellite-observed cloud properties. Results in this study reveal that on the time scale of a few days aerosol concentration is positively correlated with the frequency of moderate-rainfall (10–20 mm day−1) days but is negatively correlated with the frequency of light-rainfall (<5 mm day−1) days. Satellite observations of cloud properties show that higher aerosol concentrations are positively correlated with the increase in mixed cloud amount, cloud effective radius, cloud optical depth, and cloud-top heights; this corresponds to the decrease in low-level liquid clouds and the increase in midlevel ice–mixed clouds. Based on this analysis, the authors hypothesize that the increase in aerosol concentration results in the increase in summer rainfall frequency in China via enhanced ice nucleation in the midtroposphere. However, over the past few decades, observations show an increasing long-term trend in aerosol concentration but decreasing trends in summer rainfall frequency and relative humidity (RH) in China. Despite the short-term positive relationship between summer rainfall frequency and aerosol concentration found in this study, the long-term variations in summer rainfall frequency in China are mainly determined by other factors including RH variation possibly caused by global and regional climate changes. A continuous decrease in RH resulting in less summer rainfall frequency may further enhance aerosol concentrations in the future in conjunction with the increase in the anthropogenic emissions.


2005 ◽  
Vol 23 (7) ◽  
pp. 2425-2432 ◽  
Author(s):  
F. Liang ◽  
X. A. Xia

Abstract. Long-term trends in downwelling solar irradiance and associated climatic factors over China are studied in the paper. Decreasing trends in global and direct radiation are observed over much of China. The largest decrease occurs in South and East China (east of about 100° E and south of about 40° N). The spatial pattern of observed trends in diffuse irradiance is complex and inhomogeneous. An intriguing aspect of trends in global and direct irradiance is the rather abrupt decrease in annual and seasonal mean values from 1978 onward. The decreasing trends in solar radiation in China did not persist into the 1990s. The spatial and temporal patterns of trends in sunshine duration are consistent with that of global and direct irradiance. A decreasing trend in rainy days is observed over much of China, which is in agreement with the secular trend in cloud amount. The fact that trends in cloud amount and solar radiation are quite similar suggests that the cloud amount is not the primary cause for the decrease in solar radiation. Visibility in the eastern part of China has deteriorated heavily as a result of the rapid increase in aerosol loading. The statistical analysis showed that atmospheric transmission under clear conditions decreased rapidly. These facts suggest that the rapid increase in aerosol loading should be one of the principle causes for the decrease in solar radiation. The observed diurnal temperature range decreases remarkably in China, which is closely related to the increase in aerosols. The effects of anthropogenic air pollutants on climate should be further studied and included in the simulation of climate and projection of climate scenario. Keywords. Atmospheric composition and structure (Aerosol and particles; General or miscellaneous) – Meteorology and atmospheric dynamics (Radiative processes)


2021 ◽  
Vol 39 (3) ◽  
Author(s):  
Inna Deineha ◽  
Anatoly Maslov ◽  
Natalia Potryvaieva ◽  
Uliana Berezhnytska ◽  
Liudmyla Verbivska ◽  
...  

This work's relevance is due to the need to improve the use of tools to stimulate the development of enterprises and the development of effective measures of government influence on the market economy. The article discusses the institutional environment's main characteristics in which enterprises of the real sector of the economy operate.Arguments showing the need for state support and development of small business, from the point of view of a key factor in the development of both the national economy and the factor of stabilization of the social sphere, are presented. The characteristic is given, and the main nuances of the impact and transformation of the institutional environment with the help of available tools are considered to achieve the effect of stable and long-term development of small and medium-sized enterprises.The article attempts to highlight the existing problems and the complex nature of the impact of instruments on enterprises' institutional environment.


Rheumatology ◽  
2021 ◽  
Vol 60 (Supplement_5) ◽  
Author(s):  
Sirine Miri ◽  
Wafa Triki ◽  
Kaouther Maatallah ◽  
Hanene Ferjani ◽  
Dorra Ben Nessib ◽  
...  

Abstract Background Juvenile Idiopathic Arthritis (JIA) and its related symptoms have been associated with interference in the daily life of children and adolescents with JIA including their friendships, their school attendance and sometimes their family life. The aim of the study was to describe the impact of JIA on schooling, social and family life from the point of view of children. Methods We interviewed 23 children and adolescents, diagnosed with JIA according to the classification criteria of the International League of Associations for Rheumatology (ILAR). Results The mean age of our group was 16 years, with a sex ratio of 3. Eight percent of the children were in elementary school, 21.7% in high school and 8.7% in university. Eighty-seven per cent reported school absenteeism due to JIA (pain, being hospitalized,) with a mean of 8 missed school days. Forty-three per cent failed in their schooling at some point. Thirty percent thought it was related to the consequences of their disease. Only 47.8% found the school staff to be helpful and supportive. Seventy eight percent felt understood and supported by their family in dealing with the different aspects of JIA. Twenty-six per cent felt more spoiled than their other siblings, creating tension sometimes. Fifty two percent felt different and not accepted by their peers because of the JIA. Conclusions Children with JIA are already suffering from the physical aspect of their disease. Initiating an open discussion with them might reduce the burden these children are carrying often in silence, and improve long-term outcomes in terms of schooling, social and, family life.


2016 ◽  
Vol 16 (4) ◽  
pp. 2493-2505 ◽  
Author(s):  
Ilias Fountoulakis ◽  
Alkiviadis F. Bais ◽  
Konstantinos Fragkos ◽  
Charickleia Meleti ◽  
Kleareti Tourpali ◽  
...  

Abstract. In this study, we discuss the short- and the long-term variability of spectral UV irradiance at Thessaloniki, Greece, using a long, quality-controlled data set from two Brewer spectrophotometers. Long-term changes in spectral UV irradiance at 307.5, 324 and 350 nm for the period 1994–2014 are presented for different solar zenith angles and discussed in association with changes in total ozone column (TOC), aerosol optical depth (AOD) and cloudiness observed in the same period. Positive changes in annual mean anomalies of UV irradiance, ranging from 2 to 6 % per decade, have been detected both for clear- and all-sky conditions. The changes are generally greater for larger solar zenith angles and for shorter wavelengths. For clear-skies, these changes are, in most cases, statistically significant at the 95 % confidence limit. Decreases in the aerosol load and weakening of the attenuation by clouds lead to increases in UV irradiance in the summer, of 7–9 % per decade for 64° solar zenith angle. The increasing TOC in winter counteracts the effect of decreasing AOD for this particular season, leading to small, statistically insignificant, negative long-term changes in irradiance at 307.5 nm. Annual mean UV irradiance levels are increasing from 1994 to 2006 and remain relatively stable thereafter, possibly due to the combined changes in the amount and optical properties of aerosols. However, no statistically significant corresponding turning point has been detected in the long-term changes of AOD. The absence of signatures of changes in AOD in the short-term variability of irradiance in the UV-A may have been caused by changes in the single scattering albedo of aerosols, which may counteract the effects of changes in AOD on irradiance. The anti-correlation between the year-to-year variability of the irradiance at 307.5 nm and TOC is clear and becomes clearer as the AOD decreases.


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