Spostrzeżenia dotyczące wpływu zachmurzenia na maksymalne wartości natężenia całkowitego promieniowania słonecznego

Remarks on the influence of cloudiness on the maximum values of total solar radiation intensity

Summary: The study presents the results of observations carried out in Kraków (at the research station of the Department of Climatology, Institute of Geography and Spatial Management of the Jagiellonian University) and in Gorzów Wielkopolski (at the Regional Hydrological and Meteorological Station of the Institute of Meteorology and Water Management) in the years 2004-2008. The observations examined the relationship between the intensity of total solar radiation and cloud cover with its specific generic makeup. The results of previous studies have been confirmed, stating that cloudiness has a twofold impact on solar radiation intensity: most often, it attenuates radiation, however, under specific circumstances, it can also enhance it. The maximum intensity of total radiation (over 1100 Wˇm-2 in Kraków and Gorzów Wielkopolski alike) occurs with a cloud cover of 3/8 to 6/8 of the sky, with Cumulus mediocris and congestus, as well as Cumulonimbus clouds. The highest intensity of total radiation under clear skies conditions in a given year is registered from the second half of May to July (the highest altitude of the Sun above the horizon), equalling 840-860 Wˇm-2. Under clear skies conditions, air transparency, and especially water vapour content are very significant as far as the influx of solar radiation to the surface of the Earth is concerned. On days with Stratus clouds covering the sky (8/8), differences in the intensity of radiation are substantial, due to varying thickness of the cloud, or primarily, due to the occurrence of higher clouds, invisible from the station located on the surface of the Earth. In the case of high-altitude clouds, the height of the Sun above the horizon is very important - with the Sun located low above the horizon, the radiation is substantially limited.

Słowa kluczowe: natężenie całkowitego promieniowania słonecznego, stopień zachmurzenia, rodzaje chmur, transmisja promieniowania przez chmury

Słowa kluczowe (w języku angielskim): total solar radiation intensity, cloudiness, cloud genera, solar radiation transmission through the clouds

Prace Geograficzne, 2009, z. 122, s. 39-48.

Instytut Geografii i Gospodarki Przestrzennej UJ

ISSN 1644-3586

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