{"title":"Remote sensing-based spatio-temporal rainfall variability analysis: the case of Addis Ababa City, Ethiopia","authors":"Esubalew Nebebe Mekonnen, Ephrem Gebremariam, Aramde Fetene, Shimeles Damene","doi":"10.1007/s12518-024-00554-x","DOIUrl":null,"url":null,"abstract":"<div><p>Climate variability is a highly debated and unavoidable global environmental challenge that has adverse effects on Ethiopia, a developing country. Hence, the objective of this research is to examine the changes in rainfall patterns in Addis Ababa City, Ethiopia, from 1981 to 2018, considering both spatial and temporal aspects. The study utilized a time-series dataset of climate information, which had a spatial resolution of 4 × 4 km, obtained from the National Meteorological Agency of Ethiopia. Supplementary data was also acquired from the Ethiopian Space Science and Geospatial Institute. To examine the rainfall variability, statistical measures such as the coefficient of variation (CV) and standardized anomaly index (SAI) were employed. Geospatial technologies and “R” programming were also used to perform a non-parametric Mann-Kendall (MK) test and Sen’s slope estimator for the investigation of both the trend and magnitude of changes. The annual, <i>Kiremt</i> (main rainy), and <i>Belg</i> (spring) seasons rainfall exhibited low to moderate variability with CV < 20% and CV < 30%, respectively, and very high variability for the <i>Belg</i> season (CV > 30%). The <i>Bega</i> season’s variability was extreme (CV > 70%). In contrast, decadal rainfall variability was generally very low (CV < 10%). The months from October to March showed higher inter-monthly variability, with CV exceeding 100%. In contrast, the <i>Kiremt</i> season, July, and August, experienced lower inter-monthly variability (CV < 30%). The western, north-east, and southern parts of Addis Ababa demonstrated relatively higher rainfall variability, and the trends decreased in all seasons and months, except the <i>Kiremt</i> season and the months of May, June, and September. However, none of these seasonal and monthly changes were statistically significant (<i>P</i> > 0.05). The study identified 6 years (1982, 1984, 1997, 1999, 2014, and 2015) with varying degrees of drought. Consequently, the spatio-temporal variability of precipitation should be considered in development plans, disaster risk reduction strategies, and policy measures such as flood management.</p></div>","PeriodicalId":46286,"journal":{"name":"Applied Geomatics","volume":null,"pages":null},"PeriodicalIF":2.3000,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Applied Geomatics","FirstCategoryId":"1085","ListUrlMain":"https://link.springer.com/article/10.1007/s12518-024-00554-x","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"REMOTE SENSING","Score":null,"Total":0}
引用次数: 0
Abstract
Climate variability is a highly debated and unavoidable global environmental challenge that has adverse effects on Ethiopia, a developing country. Hence, the objective of this research is to examine the changes in rainfall patterns in Addis Ababa City, Ethiopia, from 1981 to 2018, considering both spatial and temporal aspects. The study utilized a time-series dataset of climate information, which had a spatial resolution of 4 × 4 km, obtained from the National Meteorological Agency of Ethiopia. Supplementary data was also acquired from the Ethiopian Space Science and Geospatial Institute. To examine the rainfall variability, statistical measures such as the coefficient of variation (CV) and standardized anomaly index (SAI) were employed. Geospatial technologies and “R” programming were also used to perform a non-parametric Mann-Kendall (MK) test and Sen’s slope estimator for the investigation of both the trend and magnitude of changes. The annual, Kiremt (main rainy), and Belg (spring) seasons rainfall exhibited low to moderate variability with CV < 20% and CV < 30%, respectively, and very high variability for the Belg season (CV > 30%). The Bega season’s variability was extreme (CV > 70%). In contrast, decadal rainfall variability was generally very low (CV < 10%). The months from October to March showed higher inter-monthly variability, with CV exceeding 100%. In contrast, the Kiremt season, July, and August, experienced lower inter-monthly variability (CV < 30%). The western, north-east, and southern parts of Addis Ababa demonstrated relatively higher rainfall variability, and the trends decreased in all seasons and months, except the Kiremt season and the months of May, June, and September. However, none of these seasonal and monthly changes were statistically significant (P > 0.05). The study identified 6 years (1982, 1984, 1997, 1999, 2014, and 2015) with varying degrees of drought. Consequently, the spatio-temporal variability of precipitation should be considered in development plans, disaster risk reduction strategies, and policy measures such as flood management.
期刊介绍:
Applied Geomatics (AGMJ) is the official journal of SIFET the Italian Society of Photogrammetry and Topography and covers all aspects and information on scientific and technical advances in the geomatics sciences. The Journal publishes innovative contributions in geomatics applications ranging from the integration of instruments, methodologies and technologies and their use in the environmental sciences, engineering and other natural sciences.
The areas of interest include many research fields such as: remote sensing, close range and videometric photogrammetry, image analysis, digital mapping, land and geographic information systems, geographic information science, integrated geodesy, spatial data analysis, heritage recording; network adjustment and numerical processes. Furthermore, Applied Geomatics is open to articles from all areas of deformation measurements and analysis, structural engineering, mechanical engineering and all trends in earth and planetary survey science and space technology. The Journal also contains notices of conferences and international workshops, industry news, and information on new products. It provides a useful forum for professional and academic scientists involved in geomatics science and technology.
Information on Open Research Funding and Support may be found here: https://www.springernature.com/gp/open-research/institutional-agreements