In order to investigate effects of interactions between turbulence and gravity waves in the stable boundary layer on similarity theory relationships, we re-examined a dataset, collected during three April nights in 1978 and in 1980 on the 300-m tower of the Boulder Atmospheric Observatory (BAO). The BAO site, located in Erie, Colorado, USA, 30 km east of the foothills of the Rocky Mountains, has been known for the frequent detection of wave activities. The considered profiles of turbulent fluxes and variances were normalized by two local, gradient-based scaling systems, and subsequently compared with similarity functions of the Richardson number, obtained based on data with no influence of gravity currents and topographical factors. The first scaling system was based on local values of the vertical velocity variance \(\sigma _\mathrm{w}\) and the Brunt–Väisäla frequency\( N,\) while the second one was based on the temperature variance \(\sigma _{\theta }\) and \(N.\) Analysis showed some departures from the similarity functions (obtained for data with virtually no influence of mesoscale motions); nonetheless the overall dependency of dimensionless moments on the Richardson number was maintained.
Psoriasis is a multifactorial, chronic, and inflammatory disease that severely impacts patients’ quality of life. The disease is caused by genetic irregularities affected by epigenetic and environmental factors. Some of these factors may include seasonal changes, such as solar radiation, air pollution, and humidity, and changes in circadian rhythm, especially in the temporal and polar zones. Thus, some psoriasis patients report seasonal variability of symptoms. Through a comprehensive review, we aim to delve deeper into the intricate interplay between seasonality, environmental factors, and the genetic and epigenetic landscape of psoriasis. By elucidating these complex relationships, we strive to provide insights that may inform targeted interventions and personalized management strategies for individuals living with psoriasis.
3 November 2016 in Atmospheric Chemistry and Physics
Specific aerosols and cloud properties over large urban regions seem to generate an island, similar to the well-known urban heat island, leading to lower ultraviolet (UV) radiation intensity compared to the surrounding less polluted areas, thus creating a shield against excessive human exposure to UV radiation. The present study focuses on differences between erythemal and UVA (324 nm) doses measured by the Brewer spectrophotometers in Warsaw (52.3° N, 21.0° E) and Belsk (51.8° N, 20.8° E). The latter is a rural region located about 60 km south-west of the city. Ratios between erythemal and UVA partly daily doses, obtained during all-sky and cloudless-sky conditions for the period May 2013–December 2015, were analysed to infer a specific cloud and aerosol forcing on the surface UV doses over Warsaw. Radiative model simulations were carried out to find sources of the observed differences between the sites. It was found that Warsaw urban agglomeration induced 8 and 6 % attenuation of the erythemal and UVA doses respectively. This is mostly due to the lower sun elevation in Warsaw during the near-noon measurements and the larger optical depth of the city aerosols and increased cloudiness. It could be hypothesised that the expected stronger absorption of the solar UV radiation by urban aerosols is compensated for here by a higher surface reflectivity over the city.
7 November 2019 in International Journal of Climatology
Ultraviolet radiation (UVR) has a detrimental impact on human health. Overexposures can lead to erythema and DNA damage causing various skin cancers, including the most dangerous melanoma. Recently, a large increase in melanoma incidents has been detected in Europe. We search for a link between the increase of the skin cancer incidence rate and early spring (April) trends in surface UVR and meteorological parameters (temperature, cloudiness, and precipitation) for several European sites: Belsk (Poland), Oslo (Norway), Reading (UK), and Uccle (Belgium). The trends are calculated for the periods of 1980‐2004 and 2005‐2018 using ground‐based UV measurements and the reconstructed data by a multi‐linear regression model. The April trends are of special interest because after winter the human skin is not adapted to high UVR intensity and thus susceptible to solar exposure. Statistically insignificant UV trends are found for all stations except for Belsk with the trend of ~5% per 10 yr. in the former period. Positive trends of 0.5‐1.0oC per 10 yr. (statistically significant) were calculated for all stations in the mean daily maximum temperature of April in the period 1980‐2018. In April, total ozone values are negatively correlated with the daily maxima of the surface temperature, so if the temperature is higher than 15oC, the corresponding total ozone values will go below the long‐term mean, causing more intense surface UVR. Moreover, high temperatures in April may encourage people to stay longer in the sun and expose parts of the body previously covered by winter clothing, which may result in numerous sunburns yielding a higher risk of melanoma. Thus, social campaigns promoting healthy scenarios of outdoor activities should start earlier than before i.e. at the beginning of spring not just before the summer vacation.
Ultraviolet solar radiation at the Earth’s surface significantly impacts both human health and ecosystems. A biologically effective daily radiant exposure (BEDRE) model is proposed for various biological processes with an analytical formula for its action spectrum. The following processes are considered: erythema formation, previtamin D3 synthesis, psoriasis clearance, and inactivation of SARS-CoV-2 virions. The BEDRE model is constructed by multiplying the synthetic BEDRE value under cloudless conditions by a cloud modification factor (CMF) parameterizing the attenuation of radiation via clouds. The CMF is an empirical function of the solar zenith angle (SZA) at midday and the daily clearness index from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) measurements on board the second-generation Meteosat satellites. Total column ozone, from MERRA-2 reanalysis, is used in calculations of clear-sky BEDRE values. The proposed model was trained and validated using data from several European ground-based spectrophotometers and biometers for the periods 2014–2023 and 2004–2013, respectively. The model provides reliable estimates of BEDRE for all biological processes considered. Under snow-free conditions and SZA < 45° at midday, bias and standard deviation of observation-model differences are approximately ±5% and 15%, respectively. The BEDRE model can be used as an initial validation tool for ground-based UV data.
1 July 2015 in Journal of Photochemistry and Photobiology B: Biology