Search results for " solar radiation"

Study of erythemal, UV (A + B) and global solar radiation in Valencia (Spain)

2008

Although ultraviolet B radiation (UVB), the solar radiation band between 280 and 315 nm, is only a small fraction of the extraterrestrial solar radiation, it accounts for 80% of the harmful effects of exposure to the sun. In this work values of erythemal solar irradiance (UVER) measured in Valencia on a horizontal plane in the period between June 2003 and June 2005 are analysed and compared with measures of UV (A+B) and global irradiances on a horizontal plane. UV erythemal (UVER) irradiance has been measured using a YES-UVB-1 broadband radiometer; UV (A+B) irradiance has been measured using a TUVR Eppley radiometer with spectral response between 290 and 385 nm and global irradiance on a ho…

Operational considerations to improve total ozone measurements with a Microtops II ozone monitor

2012

A Microtops II "ozone monitor" with UV channels centered at 305.5, 312.5, and 320 nm has been used routinely in six experimental campaigns carried out in several geographic locations and seasons, covering latitudes from 35 to 68° N during the last ten years (2001–2011). The total ozone content is retrieved by Microtops II by using different combinations (Channel I, 305.5/312.5 nm; Channel II, 312.5/320 nm; and Channel III, 305.5/312.5/320 nm) of the signals at the three ultraviolet wavelengths. The long-term performance of the total ozone content determination has been studied taking into account the sensitivities to the calibration, airmass, temperature and aerosols. When a calibration was…

On the determination of coherent solar climates over a tropical island with a complex topography

2020

Abstract Many tropical islands aim at developing a greener self-sufficient energy production systems based on renewable energy, notably solar-generated electricity. This work explores the mean diurnal and annual solar cycles over La Reunion island (southwest Indian Ocean: 21°S, 55.5°E), and their spatial behavior, using the Solar surfAce RAdiation Heliosat – East (SARAH-E) satellite-derived data at high spatial ( 0.05 ° × 0.05 ° ) and time (hourly) resolutions over period 1999–2016. Comparisons of the SARAH-E data with ground-based measurements over the period 2011–2015 show differences of ~ 15 % for diurnal-seasonal variations. The solar resource over the island displays strong spatial var…

Stima della radiazione solare giornaliera in sicilia mediante i dati di temperatura massima e minima

2009

By using thermometric data series from 36 sicilian stations , the authors use different relationship for indirect determination of daily solar radiation. The best performance was given by Hargreaves-Samani formula which is then parameterized by the authors for the investigated region.

Validation of a very simple model for computing global solar radiation in the European, African, Asian and North American areas

1990

Abstract In a previous paper Coppolino has proposed a very simple model for predicting the monthly mean daily global solar radiation G (MJm −2 day −1 ) at any Italian location using as input only the sunshine duration s (hours) and the noon altitude of the sun on the 15th of the month h n (degrees). The correlation suggested is G = 7.8 s 0.5 (sin h n ) 1.15 . Herein the validity of this model is verified by extending its application to dat from 24 stations displaced at various latitudes, altitudes above sea level and geographical situations in the European, African, Asian and North American areas. Furthermore the validity of this model to fit the data of the tested stations is compared with…

Global solar radiation in Italy

1978

An analysis of direct solar transmittance and atmospheric turbidity in the Mediterranean climatic belt

1989

Abstract The empirical model developed by King and Buckius for the direct transmission in clear sky is applied to hourly data of two Yugoslav locations exhibiting typical meteoclimatic characteristics common to the whole Mediterranean belt. The occurrence of “very clear”, “clear” and “very hazy” hours, after the usually accepted definitions, is determined and discussed. The degree of accuracy of the previsional model is investigated performing the comparison with the corresponding values obtained directly by energetic procedure. A general overestimate of the transmittance is experienced with notable deviations in meteorological conditions affected by the presence of dense clouds which behav…

A very simple model for computing global solar radiation

1990

Abstract In this paper a very simple model for predicting the daily global solar radiation at any Italian location using as input of a few extensively measured meterological parameters is proposed. In fact the daily radiation G (MJ m−2) is here correlated only with the sunshine duration s (h) and the noon altitude of the sun on the 15th of the month h n (degrees) by the following equation: G= Ks 0.5 (sin h n ) 1.15 where only one value of the factor K is used. The validity of this formula is verified fixing K = 7.8 and using the data from 34 Italian stations displaced at various latitudes, altitudes or geographical situations (inland or coastal site). The test results show that the deviatio…

Assessment of the mean radiant temperature in urban areas: methods at comparison

2018

Mean radiant temperature may play a pivotal role in the assessment of the outdoor environmental conditions in urban areas. However, its assessment in urban settings is not a simple task owing to the presence of complex and articulated environment and of solar radiation. The article aims to perform a comparison among the results yielded by different methods: the globe-thermometer method, and the six-directional technique. The scope of such a survey is an analysis of the actual appropriateness of the more practical, albeit less accurate, globe-thermometer method to outdoor environments. Furthermore, an analytical model, previously elaborated by the authors and here modified to make it applica…

The importance of reliable climatic data in the urban energy policy

2011

In the last years, more and more attention has been focused on energy issues, in particular at urban level, as it is pointed out by the Directive 2002/91/EC on the Energy Performance of Buildings. In fact, the building sector encompasses nearly 30% of the energy whole consumptions. To try to limit such consumptions, both central and local governments should plan effective policies, such as promoting the use of renewable sources and of more energy efficient buildings (e.g. by means of green coverings). But in order to do that, local administrations should provide reliable tools for engineers and technicians to plan such systems. Nowadays, several software are available; the weak point is the…