Evaluation and Application of Multi-Source Satellite Rainfall Product CHIRPS to Assess Spatio-Temporal Rainfall Variability on Data-Sparse Western Margins of Ethiopian Highlands

Ashebir  Sewale Belay; Ayele  Almaw Fenta; Alemu Yenehun; Fenta Nigate; Seifu  A. Tilahun; Michael  M. Moges; Mekete Dessie; Enyew Adgo; Jan Nyssen; Margaret Chen; Ann  Van Griensven; Kristine Walraevens

doi:10.3390/rs11222688

Remote Sensing (Nov 2019)

Evaluation and Application of Multi-Source Satellite Rainfall Product CHIRPS to Assess Spatio-Temporal Rainfall Variability on Data-Sparse Western Margins of Ethiopian Highlands

Ashebir Sewale Belay,
Ayele Almaw Fenta,
Alemu Yenehun,
Fenta Nigate,
Seifu A. Tilahun,
Michael M. Moges,
Mekete Dessie,
Enyew Adgo,
Jan Nyssen,
Margaret Chen,
Ann Van Griensven,
Kristine Walraevens

Affiliations

Ashebir Sewale Belay: School of Earth Sciences and Blue Nile Water Institute, Bahir Dar University, P.O. Box 79, Bahir Dar, Ethiopia
Ayele Almaw Fenta: Arid Land Research Centre, Tottori University, 1390 Hamasaka, Tottori 680-0001, Japan
Alemu Yenehun: School of Earth Sciences and Blue Nile Water Institute, Bahir Dar University, P.O. Box 79, Bahir Dar, Ethiopia
Fenta Nigate: School of Earth Sciences and Blue Nile Water Institute, Bahir Dar University, P.O. Box 79, Bahir Dar, Ethiopia
Seifu A. Tilahun: School of Civil & Water Resources Engineering, Bahir Dar University, P.O. Box 430, Bahir Dar, Ethiopia
Michael M. Moges: School of Civil & Water Resources Engineering, Bahir Dar University, P.O. Box 430, Bahir Dar, Ethiopia
Mekete Dessie: School of Civil & Water Resources Engineering, Bahir Dar University, P.O. Box 430, Bahir Dar, Ethiopia
Enyew Adgo: Department of Natural Resource, Bahir Dar University, P.O. Box 79, Bahir Dar, Ethiopia
Jan Nyssen: Department of Geography, Ghent University, Krijgslaan 281 (S8), B-9000 Ghent, Belgium
Margaret Chen: Department of Hydrology and Hydraulic Engineering, Faculty of Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
Ann Van Griensven: Department of Hydrology and Hydraulic Engineering, Faculty of Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
Kristine Walraevens: Laboratory for Applied Geology and Hydrogeology, Department of Geology, Ghent University, Krijgslaan 281 (S8), B-9000 Ghent, Belgium

DOI: https://doi.org/10.3390/rs11222688
Journal volume & issue: Vol. 11, no. 22
p. 2688

Abstract

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The spatio-temporal characteristic of rainfall in the Beles Basin of Ethiopia is poorly understood, mainly due to lack of data. With recent advances in remote sensing, satellite derived rainfall products have become alternative sources of rainfall data for such poorly gauged areas. The objectives of this study were: (i) to evaluate a multi-source rainfall product (Climate Hazards Group Infrared Precipitation with Stations: CHIRPS) for the Beles Basin using gauge measurements and (ii) to assess the spatial and temporal variability of rainfall across the basin using validated CHIRPS data for the period 1981−2017. Categorical and continuous validation statistics were used to evaluate the performance, and time-space variability of rainfall was analyzed using GIS operations and statistical methods. Results showed a slight overestimation of rainfall occurrence by CHIRPS for the lowland region and underestimation for the highland region. CHIRPS underestimated the proportion of light daily rainfall events and overestimated the proportion of high intensity daily rainfall events. CHIRPS rainfall amount estimates were better in highland regions than in lowland regions, and became more accurate as the duration of the integration time increases from days to months. The annual spatio-temporal analysis result using CHIRPS revealed: a mean annual rainfall of the basin is 1490 mm (1050−2090 mm), a 50 mm increase of mean annual rainfall per 100 m elevation rise, periodical and persistent drought occurrence every 8 to 10 years, a significant increasing trend of rainfall (~5 mm year−1), high rainfall variability observed at the lowland and drier parts of the basin and high coefficient of variation of monthly rainfall in March and April (revealing occurrence of bimodal rainfall characteristics). This study shows that the performance of CHIRPS product can vary spatially within a small basin level, and CHIRPS can help for better decision making in poorly gauged areas by giving an option to understand the space-time variability of rainfall characteristics.

Published in Remote Sensing

ISSN: 2072-4292 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Science
Website: http://www.mdpi.com/journal/remotesensing/

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