Title: Climatic and spatial variations in seasonality index of rainfall pattern for major Australian cities

Authors: Monzur A. Imteaz; Abdullah Yilmaz; Amimul Ahsan

Addresses: Department of Civil and Construction Engineering, Swinburne University of Technology, Melbourne, VIC 3122, Australia ' Department of Engineering, La Trobe University, Victoria 3552, Australia ' Department of Civil and Environmental Engineering, Islamic University of Technology (IUT), Gazipur, Bangladesh; Department of Civil and Construction Engineering, Swinburne University of Technology, Australia

Abstract: It is a traditional practice to assign a single value for the 'seasonality index' for a particular city. However, for a large city a single 'seasonality index' value may not be appropriate. Through analysing historical data, this paper presents spatial variations of seasonality index (SI) values in six major cities of Australia. The paper also presents the inter-annual variations of SI values within dry, average and wet years. Four rainfall stations in the farthest four corners at each city were chosen for this analysis to see the extent of spatial variability. Historical data was also segregated into dry, average and wet years. Wide ranges of variations are observed in both spatially and under different weather conditions. It is found that locations closer to the ocean exhibit lower SI values, whereas locations situated in high elevations exhibit higher SI values. Also, Melbourne has got the highest spatial variation of SI values, followed by Adelaide and Sydney. In regards to climatic variability, there is no certain trend observed; for some cities (Sydney, Melbourne) SI decreases with the increase in annual rainfall amounts, whereas for some other cities (Brisbane, Perth) it is opposite.

Keywords: seasonality index; inter-annual variation; spatial variation; rainfall.

DOI: 10.1504/IJHST.2022.123644

International Journal of Hydrology Science and Technology, 2022 Vol.14 No.1, pp.14 - 26

Received: 01 Aug 2020
Accepted: 06 Sep 2020
Published online: 30 Jun 2022 *

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