VARIABILITY OF PRECIPITATION OVER ETHIOPIA BY USING WAVELET TRANSFORM

Shambel Tsega

dc.contributor.author	Shambel Tsega
dc.date.accessioned	2020-12-17T12:06:44Z
dc.date.available	2020-12-17T12:06:44Z
dc.date.issued	2020-12-17
dc.identifier.uri	http://hdl.handle.net/123456789/11744
dc.description.abstract	Atmospheric variables like precipitation, stream flow are significantly influenced by various climatic factors and large-scale atmospheric circulation patterns. Investigations for the variation of rainfall by different large-scale oceanic impacts are very fundamental for the economy and climatic maintenance of the country. The study examines the variability of precipitation over Ethiopia through the analysis of monthly and annual rainfall data at five stations from north, east, west, south and central part of Ethiopia from 19872017 for 31 years. Standardized precipitation ratio (Ip) and wavelet analyses were applied to examine the spatio-temporal variability of precipitation and to determine the effect of oceanic fluctuations on rainfall variability. The calculated standard precipitation index (Ip) indicates year to year variability of rainfall over Ethiopia, which lies between 3.2 and -2.The continuous wavelet technique applied to yearly time series of precipitations over five stations of Ethiopia reveals short and long-term periodicities like 2-3, 3-5 and 6-10 years at different time periods. The oceanic indices reveals long term oscillations like 2-3, 3-5, 6-10 and 8-13 years over different time periods. The rainfall and oceanic fluctuations shows similar periodicity in some part of Ethiopia. Our analysis reveals that the Northern part of Ethiopia is negatively affected by Nino-4 during 1992-2003 with a flood event (wet 2.5) around 2001, southern part is negatively affected by NAO during 2009-2016 with a severe drought (dry -2) in 2014/2015, western part is negatively affected by SOI during 1992-2005 with two severe droughts observed around 1994/1995 (dry -1.8) and 2003 (dry -2), eastern part is negatively afxiii fected by MOI during 1995-2000 with a drought around 2000/2001 and central part is negatively affected by Nino-4 during 2002-2010 with a drought (dry -1.3) around 2004/2005	en_US
dc.language.iso	en	en_US
dc.subject	Physics	en_US
dc.title	VARIABILITY OF PRECIPITATION OVER ETHIOPIA BY USING WAVELET TRANSFORM	en_US
dc.type	Thesis	en_US