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Please use this identifier to cite or link to this item: http://hdl.handle.net/10362/8320

Título: Spatial-temporal analyses of climate elements, vegetation characteristics and sea surface temperature anomaly. A Case study in Gojam, Ethiopia
Autor: Getahun, Yitea Seneshaw
Orientador: Costa, Ana Cristina
Mahiques, Jorge Mateu
Pebesma, Edzer
Palavras-chave: Climate elements and Variability
La Niña or El Niño Southern Oscillation
Normalize different vegetation indices
Remote sensing
Spatial and temporal
Issue Date: 1-Mar-2012
Relatório da Série N.º: Master of Science in Geospatial Technologies;TGEO0075
Resumo: Agriculture is the backbone of Gojjam economy as it depends on seasonal characteristics of rainfall. This study analyses the components of regional climate variability, especially La Niña or El Niño Southern Oscillation (ENSO) events and their impact on rainfall variability and the growing season normalized difference vegetation index. The temporal and spatial distribution of temperature, precipitation and vegetation cover have been investigated statistically in two agricultural productive seasons for a period of 9 years (2000–2008), using data from 11 meteorological station and MODIS satellite data in Gojam, Ethiopia. The normalized difference vegetation index (NDVI) is widely accepted as a good indicator for providing vegetation properties and associated changes for large scale geographic regions. Investigations indicate that climate variability is persistent particularly in the small rainy season Belg and continues to affect vegetation condition and thus Belg crop production. Statistical correlation analyses shows strong positive correlation between NDVI and rainfall in most years, and negative relationship between temperature and NDVI in both seasons. Although El Niño and La Niña events vary in magnitude in time, ENSO analyses shows that two strong La Niña years and one strong El Niño years. ENSO analyses result shows that its impact to the region rainfall variability is mostly noticeable but it is inconsistent and difficult to predict all the time. The NDVI anomaly patterns approximately agree with the main documented precipitation and temperature anomaly patterns associated with ENSO, but also show additional patterns not related to ENSO. The spatial and temporal analyses of climate elements and NDVI values for the growing season shows that NDVI and rainfall are very unstable and variable during the 9 years period. ENSO /El Niño and La Niña events analyses shows an increase of vegetation coverage during El Niño episodes contrasting to La Niña episodes. Moreover, El Niño years are good for Belg crop production.
Descrição: Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.
URI: http://hdl.handle.net/10362/8320
Appears in Collections:ISEGI - MSc Dissertations Geospatial Technologies (Erasmus-Mundus)

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