Janusz Jarosławski

Effects of clouds on the surface erythemal UV-B irradiance at northern midlatitudes: estimation from the observations taken at Belsk, Poland (1999–2001)

Abstract Results of 2-year measurements at Belsk, Poland, have been analyzed to investigate the effects of clouds on ultraviolet (UV) radiation. Data were collected using a Solar Light UV-biometer 501A (erythemally weighed UV irradiances), Kipp&Zonnen CM11 pyranometer (total solar radiation), and SCI-TEC Brewer Spectrophotometer (total ozone, aerosol and thin cloud optical depth). Hourly reports on total cloud cover and cloud type were also used in this study. It is found that overcast conditions prevail over central Poland and the sky is covered mainly by low-level clouds. The averaged cloud properties derived from visual observations correspond with those estimated from satellite measurements. An empirical relationship has been postulated for the cloud reduction factor of the erythemally weighted UV radiation as a function of the cloud reduction factor for total solar radiation. The relation may be used to reconstruct the past UV-time series. It is established that information of cloud amount and type to estimate the UV-B attenuation provides a substantial uncertainty. Stronger attenuation of the UV radiation by real clouds was found than that estimated by a radiative transfer model when examining results of the cloud optical depth at 320 nm and the cloud attenuation of the UV radiation measurements. The reduction of the erythemally weighted UV irradiance by thin clouds seems to be independent of the cloud type. It is reported that 1.4% of UV-B irradiance measurements were cloud enhanced in the snowless period of the year. The maximum UV-B enhancement of ∼20% greater than an equivalent clear-sky value was found. Numerous enhancements occurred when high-, mid-, and low- (broken Cu) clouds appeared simultaneously. Similar range of the observed enhancements and cloud composition as in previous cloud enhancement studies (over low latitudinal regions) suggest that common mechanisms may govern this phenomenon in low- and mid-latitudinal regions.

A mathematical model for seasonal variability of vitamin D due to solar radiation

It is widely recognized that vitamin D deficiency has detrimental health consequences. The ultraviolet (UV) B radiation increases the serum vitamin D level, expressed by 25-hydroxyvitamin-D(3) [25(OH)D]. An analytical model is presented to calculate the serum 25(OH)D changes throughout a year, caused by the solar exposure variability due to geophysical and habitual factors. The model is tuned by taking into account recent experimental results of serum 25(OH)D changes, after a series of artificial (by fluorescent tubes) UV exposures. The model uses the erythemal and vitamin D weighted irradiances, inferred from the Brewer spectrophotometer and the Kipp and Zonen broad-band meter measurements, carried out in Belsk (52°N, 21°E), Poland, in 2010. The modeled seasonal pattern of the serum 25(OH)D concentration in Polish indoor workers is only slightly different, than in subjects with typical outdoor activity habits, and in those with sun-seeking behavior. A deep minimum in the serum 25(OH)D concentration appears in late winter, regardless of outdoor activity habits. An extra sunbathing to boost the vitamin D level is not worth taking, because of a minor improvement of the vitamin D status, and because of a greater erythema risk. It would be much safer and more effective to maintain an adequate vitamin D level through diet supplements, even in summer, for non sun-seeking subjects.

On an improvement of UV index forecast: UV index diagnosis and forecast for Belsk, Poland, in Spring/Summer 1999

Abstract A forecast of the UV index for the following day is presented. The standard approach to the UV index modelling is applied, i.e., the clear-sky UV index is multiplied by the UV cloud transmission factor. The input to the clear-sky model (tropospheric ultraviolet and visible—TUV model, Madronich, in: M. Tevini (Ed.), Environmental Effects of Ultraviolet Radiation, Lewis Publisher, Boca Raton, 1993, p. 17) consists of the total ozone forecast (by a regression model using the observed and forecasted meteorological variables taken as the initial values of aviation (AVN) global model and their 24-hour forecasts, respectively) and aerosols optical depth (AOD) forecast (assumed persistence). The cloud transmission factor forecast is inferred from the 24-h AVN model run for the total (Sun+sky) solar irradiance at noon. The model is validated comparing the UV index forecasts with the observed values, which are derived from the daily pattern of the UV erythemal irradiance taken at Belsk ( 52° N , 21° E ), Poland, by means of the UV Biometer Solar model 501A for the period May–September 1999. Eighty-one percent and 92% of all forecasts fall into ±1 and ±2 index unit range, respectively. Underestimation of UV index occurs only in 15%. Thus, the model gives a high security in Sun protection for the public. It is found that in ∼35% of all cases a more accurate forecast of AOD is needed to estimate the daily maximum of clear-sky irradiance with the error not exceeding 5%. The assumption of the persistence of the cloud characteristics appears as an alternative to the 24-h forecast of the cloud transmission factor in the case when the AVN prognoses are not available.

Eyjafjallajokull volcano ash observed over Belsk (52° N, 21° E), Poland, in April 2010

Eruption of Eyjafjallajökull volcano took place on 13–14 April 2010, and created an ash cloud moving towards densely populated areas in Europe. Dispersion models show that the cloud appeared over Poland at noon on 16 April. Measurements of optical properties of the atmospheric aerosols by the Cimel Sun Photometer (optical thickness and volume size distribution) and lidar (backscatter coefficient) at Belsk (52° N, 21° E) for the period 15–26 April 2010 are examined to find volcanic ash in the atmosphere over the site. Thin aerosol clouds, linked to the volcanic eruption, were found below 5 km, and their optical thickness (at 500 nm) varied only slightly in the range of a few hundredths. The optical depth of the aerosol clouds in the 5–7.5 km layer was less than 0.01.

Space-based estimation of the solar UV-B doses for psoriasis heliotherapy in Poland using OMI data for the period 2005-2011.

A UV model is proposed to reconstruct the biologically weighted doses at the ground-level, erythemal, vitamin D(3), and antipsoriatic effective doses, based on the space data from the Ozone Monitoring Instrument on board of NASA EOS Aura spacecraft for the period 2005-2011. The model is training using the results of spectral UV measurements carried out at Belsk, Poland. The model outcome is verified using the UV spectra measured at Hradec Kralove, Czech Republic. The model uncertainty is almost the same for all examined action spectra and comparable to that found in earlier studies on differences between the satellite overpasses and ground-based erythemal data. Antipsoriatic doses, taken during 2h exposure periods near local noon, are reconstructed for selected sites in Poland to find if heliotherapy would be an alternative to standard treatment of psoriasis by tube irradiation in medical cabinets. Mountain-resort in the southern Poland, Zakopane, and rural-site in Central Poland, Belsk, are among the best location of potential heliotherapy centers in Poland for late spring/summer season. Łeba, resort on the Baltic Sea coast, is a potential heliotherapy center in June and July. The methodology to disclose possible heliotherapy periods over the territory of Poland could be extended to any region. It would help to prepare an optimal schedule of antipsoriatic heliotherapy that accounts for local weather conditions and medical standards of using UV cabinets.

Factors affecting solar UV radiation changes: a study of the new Robertson-Berger meter (UV-biometer model 501A) and Brewer data records taken at Belsk, Poland, 1993–1994

Abstract Daily doses of the erythemal solar ultra violet radiation (SUVR) reaching the ground at Belsk, Poland (52 °N, 21 °E) measured by a Brewer spectrophotometer and a UV-biometer model 501A during 1993–1994 in conjunction with daily total ozone and integrated global solar radiation observations are examined to infer their associations under all sky conditions. The observed doses are normalized using the SUVR daily doses obtained from a parametric model (a modified Bird and Riordan (1986) model). The daily variations of the normalized SUVR doses by the Brewer spectrophotometer and UV-biometer appear to be in harmony (the correlation coefficient is 0.99). A regression model is fitted to the normalized erythemal SUVR to delineate the impact of total ozone and clouds/aerosols on the SUVR. The model explains about 95% of the variance in the normalized SUVR doses and it may constitute an efficient diagnostic model for day-to-day variations of daily doses of the erythemal SUVR. It is found that the ratio of the daily value of integrated global solar radiation measured on a horizontal surface to its clear sky representative (from the Bird and Riordan (1986) model) can be used as a characteristic of the surface SUVR changes induced by atmospheric transparency changes (caused by clouds and aerosols). In view of the models results it seems possible that daily doses of the erythemal SUVR at ground level are less sensitive to the ozone changes during overcast days than those during cloudless days; participation of the SUVR in the integrated global solar radiation is almost the same during clear-sky and overcast days.

Analysis of particulate matter concentrations in mazovia region, central poland, based on 2007–2010 data

Measurement results of PM10 (particulate matter with diameters below 10 μm) concentrations performed at four stations in central Poland (2007–2010) were analyzed in terms of levels and distributions of concentrations, the number of exceedances of the limit values and the causes of these exceedances. PM10 levels were similar at suburban and rural stations, except of one station located in the vicinity of a busy street. The median of PM10 concentration ranged from 26 μg/m3 at suburban station to 44 μg/m3 at Warsaw Kerb station. Seasonal variability analysis of PM10 concentration revealed an additional maximum beyond the usual autumn-winter one. This maximum occurred in April at all stations, and corresponded to seasonal wildfires activity and dust activation in Eastern Europe. Cluster analysis of back-trajectories revealed that PM10 concentrations depend on the direction of advection of the incoming air; the highest values are registered for air of regional and southern origins, while the lowest are for the airmasses coming from the north and northwest direction.

Effectiveness of heliotherapy for psoriasis clearance in low and mid-latitudinal regions: A theoretical approach

The action spectrum for psoriasis clearance is reconstructed taking into account the results obtained in the early 1980s. The antipsoriatic action spectrum is used for weighting the medical cabinet UV spectra, and the solar spectra measured in San Diego (USA) and Belsk (Poland). The mean cumulative antipsoriatic effective dose of 450 mJ cm(-2), due to TL-01 (UVB narrowband) tubes, is taken by a patient with skin phototype II during routine 20 phototherapy sessions carried out in a phototherapy cabinet in the Medical University of Łódz. Thus, the daily mean dose of value 22.5 mJ cm(-2) is proposed as the threshold for daily solar dose for numbers of out-door exposures to clear psoriasis. We assume that the heliotherapy will last a whole month with every day 2h exposition to the direct sunlight around local noon. The heliotherapy will be successful if weather conditions permit at least 20 days with the daily exposure over the threshold. The minimum cumulative ambient erythemal dose, necessary for psoriasis clearance, is estimated as 144 standard erythema dose (SED) for the whole heliotherapy period. We find that heliotherapy could be effectively used in March through October (San Diego) and in June through August (Belsk). Thus, the heliotherapy against psoriasis is possible not only at southern resorts but even at the mid-latitude sites.

Perspectives of the antipsoriatic heliotherapy in Poland

Statistical analysis of the daily course of exposures to TL-01 tube radiation for 93 psoriatic patients from the Medical University of Łódź during 20-day phototherapy shows that the dose of 1 J/cm(2) represents a unit of single exposure necessary for psoriasis healing. This value is converted to the antipsoriatic effective dose of 317.9 J/m(2) using the TL-01 lamp irradiance spectrum and the antipsoriatic action spectrum. It is proposed that the daily exposure of 317.9 J/m(2) serves as the standard antipsoriatic dose (SAPD) providing a link between the cabinet and the out-door exposures and it could be used for planning heliotherapy in Poland. A model is proposed to calculate ambient antipsoriatic doses for 3 h exposures around the local noon (9 am-12 am GMT) based on satellite measurements of ozone and cloud characteristics. The model constants are determined by a comparison with pertaining antipsoriatic doses measured by the Brewer spectrophotometer in central Poland. It is found that 3 h exposures to solar radiation in the period 15 May-15 September provides the mean (2005-2013) doses in the range 2.7-3.1 SAPD over Poland. Thus, heliotherapy could be treated as an alternative to the cabinet phototherapy for almost 4 months. It seems that the most effective site for antipsoriatic heliotherapy is the south/east part of Poland (the Bieszczady Mountains). The heliotherapy could be carried out in existing national health centers equipped with the standard easy-to-use biometers for on-line monitoring of UV level and controlling duration of sunbathing to avoid erythema risks. It is even possible to control the antipsoriatic heliotherapy by a patient himself, using low-cost hand-held instruments measuring UV index.

The long-term variability of atmospheric ozone from the 50-yr observations carried out at Belsk (51.84°N, 20.78°E), Poland

Total ozone (TO3) and ozone vertical profile (by the Umkehr method) have been measured at Belsk (51.84°N, 20.78°E), Poland, since March 1963. The monthly mean data are analysed for the long-term changes in the period 1975–1996 and 1997–2012, that is, in the increasing and decreasing phases of the ozone-depleting substances (ODS) concentration in the mid-altitude stratosphere over the NH mid-latitudes. Standard explanatory variables are selected for the ozone variability attribution to chemical and dynamical processes. A triad of regression models with various formulae for the trend term is examined to get a synergetic effect. The trend term could be: (1) proportional to ODS, (2) piecewise linear (with the turning points in 1975 – the trend onset and in 1997 – the trend overturning), (3) represented by any smooth curve fitted to the ozone time series having ‘natural variations’ removed. Confirming the results from previous studies on the midlatitudinal ozone, the analyses show a weakening of the TO3 trend and the statistically significant positive trend in the upper stratospheric region (33–43 km) since 1997. The TO3 depletion in summer and autumn for the period 1997–2012 is found in the Umkehr data due to the ozone decrease in the lower and mid-stratosphere. A novel statistical-simulation-based test is proposed. It uses the bootstrap sample of the smooth trend pattern to calculate statistical significance of hypotheses for the trend variability. The test corroborates the results of the regression models and shows strengthening of the ozone negative trend in summer and autumn, disclosed in the Umkehr data, since about 2005.