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Understanding Metrological Aspects of Starting and Cessation of Rainfall on Upper Blue Nile Basin, Ethiopia

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dc.contributor.advisor Belete, Berhanu (PhD)
dc.contributor.author Rebuma, Wakesa
dc.date.accessioned 2021-02-23T05:21:25Z
dc.date.available 2021-02-23T05:21:25Z
dc.date.issued 2018-09
dc.identifier.uri http://etd.aau.edu.et/handle/123456789/25191
dc.description.abstract Ethiopian agriculture is mostly rain fed, whereas rainfall in the country is erratic, unreliable, and highly variable with space and time. Due to this rainfall variability frequent drought, high floods and famine have been occurring in many parts of the country. Therefore, Understanding of climate variability through study of spatial and temporal rainfall distribution is required. This study was designed to assess changes in the start, end and length of the growing season using historical daily rainfall data derived from the selected meteorological stations located in upper Blue Nile basin. In addition, the study investigates the trends of onset, cessation and length of growing period in study area and dry spell analysis. The analysis is done based on 29 years (1986 – 2014) daily rainfall of 33 stations spatially distributed on the basin and using INSTAT software, Excel 2010, TREND and ArcGIS. Rainfall onset identification was based on rainfall accumulation while cessation was based on dry spell analysis. The length of growing period was obtained from the difference between the onset and cessation. Trend of rainfall onset, rainfall cessation and length of growing period is calculated using Mann-Kendall's trend test. The result indicate that rainfall onset is more variable than rainfall cessation and also the studied trend of rainfall onset, cessation and LGP and annual number of wet days does not show clear significant trend change throughout the basin. Also Result from dry spell analysis show that the probability of getting dry spells of 7, 10, 15 and 21 days during rainy season (JJAS) is less than 5% except the stations on the eastern part of the basin. The rainfall onset and cession for Upper blue-Nile can be used as the base for different rainfed based production analysis and system development. en_US
dc.language.iso en_US en_US
dc.publisher Addis Ababa University en_US
dc.subject Rainfall en_US
dc.subject Onset en_US
dc.subject Cessation en_US
dc.subject Length of growing period en_US
dc.subject Dry spell en_US
dc.subject Trend en_US
dc.title Understanding Metrological Aspects of Starting and Cessation of Rainfall on Upper Blue Nile Basin, Ethiopia en_US
dc.type Thesis en_US

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