A new expression to estimate the solar ultraviolet irradiance from parameters usually available in radiometric networks is presented. The authors have analyzed the relation between solar ultraviolet global irradiance (290–385 nm), UV, and broadband global irradiance, G, studying as well the ratio UV/G. The analysis of the dependence between the ultraviolet global irradiance and the broadband global irradiance, both normalized to their respective extraterrestrial values, has been used in order to develop a functional dependence between both global hemispherical transmittances. The cloud radiative effect on both radiometric fluxes has also been studied. After this analysis, the authors propose a new expression to obtain ultraviolet global irradiance from only two input variables: clear-sky ultraviolet irradiance and the global broadband hemispherical transmittance. The dataset used in this paper has been registered in two-radiometric stations: one located in the outskirts of Granada (37.18°N, 3.58°... Abstract A new expression to estimate the solar ultraviolet irradiance from parameters usually available in radiometric networks is presented. The authors have analyzed the relation between solar ultraviolet global irradiance (290–385 nm), UV, and broadband global irradiance, G, studying as well the ratio UV/G. The analysis of the dependence between the ultraviolet global irradiance and the broadband global irradiance, both normalized to their respective extraterrestrial values, has been used in order to develop a functional dependence between both global hemispherical transmittances. The cloud radiative effect on both radiometric fluxes has also been studied. After this analysis, the authors propose a new expression to obtain ultraviolet global irradiance from only two input variables: clear-sky ultraviolet irradiance and the global broadband hemispherical transmittance. The dataset used in this paper has been registered in two-radiometric stations: one located in the outskirts of Granada (37.18°N, 3.58°...

Presented here is the first analysis of hourly solar ultraviolet irradiance (290–385 nm) and broadband global irradiance data, registered in a radiometric station located in the outskirts of Granada (37.18°N, 3.58°W, 660 m a.m.s.l.), an inland location in south-eastern Spain, during a 2-year period. According to the prevailing cloudless conditions, the results show that the highest UV radiation levels are received in June or July and the lowest in December. Hourly monthly means of the ratio UV to broadband solar radiation covers a range from a minimum of ca. 3% to a maximum of 5%. The higher values of this ratio are associated to cloudy situations. In this way for 1994, the lowest values of this ratio are encountered in December, and the highest value appears in May, associated with a higher frequency of cloudy days. The study of the ratio UV to global radiation hourly monthly means reveals a clear effect of the optical air mass and of the cloud cover. It is found that, the UV to broadband global radiation ratio increases with decreasing optical air mass and increasing cloud cover. © 1998 Royal Meteorological Society

Among the surface radiation budget components that are needed to understand the climate of the Earth, the thermal atmospheric radiation component is the only one that is not measured routinely, so it must be estimated indirectly. The presence of clouds substantially hampers this task, supplementing the emission of water vapour and carbon dioxide in the lower atmosphere. The methods proposed to estimate thermal atmospheric radiation often rely on a cloudless sky model and a corrective term that takes into account the cloud contribution. Several models for estimating the thermal atmospheric radiation under cloudy conditions have been tested using measurements recorded in Granada (Spain) during a period of 2 years. The cloudless sky model provides estimation with an error of about 5 per cent, whereas the cloudy skies models, after some modifications, estimate thermal atmospheric radiation with an error of about 6 per cent. Our results show the convenience of a quadratic dependence on cloud amount for cloudy skies models. In addition to this, it seems convenient to use available information about the radiative properties of clouds to assign different cloud emittances for different types of clouds within each level, especially for middle level clouds.

Exceptional circumstances in the city of Granada due to the COVID-19 lockdown have provided the opportunity to characterise the impact of humans on its urban acoustic climate. Traditional environmental noise management and urban sound planning usually take into account noise sources in the city, such as industrial activities or road traffic noise, in model estimations, as well as in empirical research. But trying to isolate human impact by itself, human activity including social activity, walking, talking or just going around the city, has always been a difficult or even impossible task. The COVID-19 lockdown measures have provided the opportunity to study urban climate as never before, affected just by natural or animal noise sources. Previous soundscape research at some iconic sites in the city of Granada carried out in 2019 before the lockdown and a special measuring campaign carried out at the same locations during the lockdown in 2020 offered valuable information on sound levels and local characteristics in order to carry out this comparison. Results show a great change in environmental noise levels that is interesting not only because of its magnitude, but also for its implications, especially at those sites where social human activity was an identifying characteristic. Natural or animal sounds became surprisingly evident at some study sites, especially where road traffic noise dramatically decreased, leading to significantly lower background noise levels. Important spectral changes are observed before and during the lockdown, suggesting a shift from anthropic to animal sources in the acoustic environment.