UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2024-11-23 1:56
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Conference: Bucharest University Faculty of Physics 2023 Meeting


Section: Atmosphere and Earth Science; Environment Protection


Title:
A comparison between the characteristics of low clouds above two regions with different climates


Authors:
Genica - Liliana SĂFTOIU GOLEA (1,2), Bogdan ANTONESCU (1), Sabina ȘTEFAN (1), Gabriela IORGA (1,3)


*
Affiliation:
1) University of Bucharest, Faculty of Physics, PO Box MG-11, 077125, Bucharest, Romania

2) “Horia Hulubei” National Institute for Nuclear Physics and Engineering, IFIN-HH, Reactorului 30, 077125, Bucharest-Magurele, Romania

3) University of Bucharest, Faculty of Chemistry, Department of Analytical Chemistry and Physical Chemistry, Bd. Regina Elisabeta 4-12, 030018, Bucharest, Romania



E-mail
liliana.golea@nipne.ro


Keywords:
low clouds, satellite data, albedo


Abstract:
Because clouds play an important role in the Earth's radiative budget and on Earth's climate, hourly satellite data from the Clouds and the Earth's Radiant Energy System (CERES) database (i.e., SYN1DEG-1Hour) were extracted for Bucharest and Cluj-Napoca, two areas under different climates, in the time frame between March 2000 and March 2022. The low clouds classification (thin, medium and tick) and their occurence were the primary goals of the study. Secondly, a comparative analysis of a series of macrophysical and microphysical cloud parameters (e.g., albedo, cover fraction, optical depth, liquid water path, and water radius) has been performed. Thin clouds proved to appear with highest frequency over both cities: 58.57 % (Bucharest) and 52.38 % (Cluj-Napoca), followed by the medium (35.85 % for Bucharest and 43.63 % for Cluj- Napoca) clouds. The thick clouds are significantly less frequent over Cluj-Napoca (3.97%) than over Bucharest (5.57 %). The study revealed differences between the cloud properties. We observed that while median cloud optical depth is higher for thin clouds over Cluj-Napoca than for the clouds over Bucharest, this parameter has higher values for clouds over Bucharest in cases of medium and thick clouds. The relative difference of the median effective radius of cloud droplets in Cluj-Napoca versus Bucharest ranged between about 2% and 6%, showing the clouds over Cluj-Napoca have larger droplets than the more polluted clouds over Bucharest. This resulted in more reflective medium and thick clouds over Bucharest than over Cluj-Napoca. The differences in cloud characteristics for each urban area provide important information for researches targeted to the understanding of the aerosol-cloud interaction, the formation and evolution of low clouds.


Acknowledgement:
SS, GI and GLSG acknowledge the support from NO Grants 2014-2021, under Project EEA-RO-NO-2019-0423, contract no 31/01.09.2020. GLSG work was also supported by the Romanian Nucleu Programme.