Relationship Between Short and Long Wave Radiation with Cloud Cover in Baghdad City

Article type: Research Article

Authors: Ibrahim, Ruaa M. | Mahdi, Zahraa S. | Nassif, Wedyan G. | Al-Taai, Osama T.^{; *}

Affiliations: Department of Atmospheric Sciences, College of Science, Mustansiriyah University, Baghdad, Iraq

Correspondence: [*] Corresponding Author. osamaaltaai77@uomustansiriyah.edu.iq

Abstract: Short waves are waves that have a short wavelength and are characterised by high frequencies. Therefore, they propagate over short distances from the source and are used for wireless communications and radio broadcasting. As for long waves, they have a long wavelength characterised by low frequencies and usually extend far from the source easily. When the clouds prevent sunlight from reaching Earth, it reflects a large part of it and absorbs part of the radiation that passes through it, so that less radiation reaches the Earth’s surface as a result of the clouds. The daily data of the high, medium, and low cloud cover, as well as the daily and annual data of solar radiation (long and short-wave radiation) were extracted from satellite data collected by the European Center for Medium-Range Weather Forecasting (ECMWF) over the Baghdad station at 00:00 am and 12:00 pm for the period (2015-2019). The study aims to find the effect of cloud cover on long and short waves and to find the type of relationship between them. The results showed that. The High and medium clouds are more visible in winter and less in summer. The clouds of all kinds decrease at 00:00 am and can be observed at noon. The relationship between solar radiation and cloud cover is inverse. In 2015 different types of clouds appeared, including low-lying cumulus and cumulus-medium. The radiation of long waves increases in the spring and summer when the amount of solar radiation entering the atmosphere is greater, and therefore the atmosphere derives its heat from these long waves emanating from the surface of the earth, at a time when the air could not absorb the short waves that make up the sun’s rays when it penetrated it. Through the Pearson coefficient test, several results were obtained, including that the relationship between high, medium, and low cloud cover, as well as total solar radiation, showed an inverse association; the more clouds there are, the less solar radiation reaches the earth’s surface.

Keywords: Solar radiation, cloud, ECMWF, Pearson test, Baghdad

DOI: 10.3233/AJW240057

Journal: Asian Journal of Water, Environment and Pollution, vol. 21, no. 5, pp. 27-36, 2024