Analysis of Rainfall Trends and Its Relationship with SST Signals in the Lake Tana Basin, Ethiopia

Weldegerima, Tesfay Mekonnen; Zeleke, Tadesse Terefe; Simane, Belay; Zaitchik, Benjamin F.; Fetene, Zewdu Alamineh

doi:10.1155/2018/5869010

Cited by 69 publications

(46 citation statements)

References 29 publications

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“…The results imply that the DRB is generally becoming more wet, which has positive impacts on agricultural production and water resources availability. The finding is consistent with previous studies that reported the southwestern part of the upper Blue Nile basin, where the DRB is located, is becoming more wetting (e.g., Mellander et al 2013;Brown et al 2017;Weldegerima et al 2018;Worku et al 2018). Moreover, the seasonal shift in rainfall reported in this study is consistent with previous studies for the upper Blue Nile basin (Berhane et al 2014;Vincent et al 2018).…”

Section: Spatiotemporal Climate Trendssupporting

confidence: 93%

Spatiotemporal climate and vegetation greenness changes and their nexus for Dhidhessa River Basin, Ethiopia

et al. 2019

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Background: Understanding spatiotemporal climate and vegetation changes and their nexus is key for designing climate change adaptation strategies at a local scale. However, such a study is lacking in many basins of Ethiopia. The objectives of this study were (i) to analyze temperature, rainfall and vegetation greenness trends and (ii) determine the spatial relationship of climate variables and vegetation greenness, characterized using Normalized Difference in Vegetation Index (NDVI), for the Dhidhessa River Basin (DRB). Quality checked high spatial resolution satellite datasets were used for the study. Mann-Kendall test and Sen's slope method were used for the trend analysis. The spatial relationship between climate change and NDVI was analyzed using geographically weighted regression (GWR) technique. Results: According to the study, past and future climate trend analysis generally showed wetting and warming for the DRB where the degree of trends varies for the different time and spatial scales. A seasonal shift in rainfall was also observed for the basin. These findings informed that there will be a negative impact on rain-fed agriculture and water availability in the basin. Besides, NDVI trends analysis generally showed greening for most climatic zones for the annual and main rainy season timescales. However, no NDVI trends were observed in all timescales for cool subhumid, tepid humid and warm humid climatic zones. The increasing NDVI trends could be attributed to agroforestry practices but do not necessarily indicate improved forest coverage for the basin. The change in NDVI was positively correlated to rainfall (r 2 = 0.62) and negatively correlated to the minimum (r 2 = 0.58) and maximum (r 2 = 0.45) temperature. The study revealed a strong interaction between the climate variables and vegetation greenness for the basin that further influences the biophysical processes of the land surface like the hydrologic responses of a basin. Conclusion: The study concluded that the trend in climate and vegetation greenness varies spatiotemporally for the DRB. Besides, the climate change and its strong relationship with vegetation greenness observed in this study will further affect the biophysical and environmental processes in the study area; mostly negatively on agricultural and water resource sectors. Thus, this study provides helpful information to device climate change adaptation strategies at a local scale.

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Section: Spatiotemporal Climate Trendssupporting

confidence: 93%

Spatiotemporal climate and vegetation greenness changes and their nexus for Dhidhessa River Basin, Ethiopia

et al. 2019

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“…e increasing trend in the rainfall amount in the midland AEZ was in line with recent ndings from Degefu and Bewket [38] in which Wolaita Sodo, as one of the meteorological stations, was found to experience an increasing trend in the average annual total rainfall (p < 0.01). Similarly, a recent study by Weldegerima et al [70] in Northern Ethiopia has documented an increase in annual rainfall with the magnitude of change being 2.20, 3.42, 6.58, and 2.88 mm/year, in Bahir Dar, Dangila, Debre Tabor, and Gondar, respectively. On the contrary, insigni cant decreasing trend was reported both in the lowland and in the highland AEZs in R10mm while it was insigni cant increasing trend in the midland AEZ.…”

Section: Number Of Heavy (R10mm) and Very Heavy (R20mm) Precipitationmentioning

confidence: 61%

Trends in Extreme Climate Events over Three Agroecological Zones of Southern Ethiopia

Esayas

Simane

Teferi

et al. 2018

Advances in Meteorology

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The study aims to assess trends in extremes of surface temperature and precipitation through the application of the World Meteorological Organization’s (WMO) Expert Team on Climate Change Detection and Indices (ETCCDI) on datasets representing three agroecological zones in Southern Ethiopia. The indices are applied to daily temperature and precipitation data. Nonparametric Sen’s slope estimator and Mann–Kendall’s trend tests are used to detect the magnitude and statistical significance of changes in extreme climate, respectively. All agroecological zones (AEZs) have experienced both positive and negative trends of change in temperature extremes. Over three decades, warmest days, warmest nights, and coldest nights have shown significantly increasing trends except in the midland AEZ where warmest days decreased by 0.017°C/year (p<0.05). Temperature extreme’s magnitude of change is higher in the highland AEZ and lower in the midland AEZ. The trend in the daily temperature range shows statistically significant decrease across AEZs (p<0.05). A decreasing trend in the cold spell duration indicator was observed in all AEZs, and the magnitude of change is 0.667 days/year in lowland (p<0.001), 2.259 days/year in midland, and 1 day/year in highland (p<0.05). On the contrary, the number of very wet days revealed a positive trend both in the midland and highland AEZs (p<0.05). Overall, it is observed that warm extremes are increasing while cold extremes are decreasing, suggesting considerable changes in the AEZs.

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“…Several other studies at various spatial and temporal scales have recognized warming trends in maximum temperature [4,20,21,28,63]. On the rate of increase, without adaptation, more than 1°C warming has adverse impacts [3].…”

Section: Variability and Trends In Annual Maximummentioning

confidence: 99%

“…Some attempts have been made on the climate trend analysis in Ethiopia, reporting mixed findings. For example, an insignificant trend was reported on the annual rainfall amount in the Nile basin [15][16][17][18][19][20][21]. Similarly, a nonsignificant trend in annual and seasonal rainfall was reported in Southwestern Ethiopia [22] and North Ethiopia [23].…”

Section: Introductionmentioning

confidence: 99%

Climate Variability and Farmers’ Perception in Southern Ethiopia

Esayas

Simane

Teferi

et al. 2019

Advances in Meteorology

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The study aims to analyze climate variability and farmers’ perception in Southern Ethiopia. Gridded annual temperature and precipitation data were obtained from the National Meteorological Agency (NMA) of Ethiopia for the period between 1983 and 2014. Using a multistage sampling technique, 403 farm households were surveyed to substantiate farmers’ perceptions about climate variability and change. The study applied a nonparametric Sen’s slope estimator and Mann–Kendall’s trend tests to detect the magnitude and statistical significance of climate variability and binary logit regression model to find factors influencing farm households’ perceptions about climate variability over three agroecological zones (AEZs). The trend analysis reveals that positive trends were observed in the annual maximum temperature, 0.02°C/year (p<0.01) in the lowland and 0.04°C/year (p<0.01) in the highland AEZs. The positive trend in annual minimum temperature was consistent in all AEZs and significant (p<0.01). An upward trend in the annual total rainfall (10 mm/year) (p<0.05) was recorded in the midland AEZ. Over 60% of farmers have perceived increasing temperature and decreasing rainfall in all AEZs. However, farmers’ perception about rainfall in the midland AEZ contradicts with meteorological analysis. Results from the binary logit model inform that farmers’ climate change perceptions are significantly influenced by their access to climate and market information, agroecology, education, agricultural input, and village market distance. Based on these results, it is recommended to enhance farm households’ capacity by providing timely weather and climate information along with institutional actions such as agricultural extension services.

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Analysis of Rainfall Trends and Its Relationship with SST Signals in the Lake Tana Basin, Ethiopia

Cited by 69 publications

References 29 publications

Spatiotemporal climate and vegetation greenness changes and their nexus for Dhidhessa River Basin, Ethiopia

Spatiotemporal climate and vegetation greenness changes and their nexus for Dhidhessa River Basin, Ethiopia

Trends in Extreme Climate Events over Three Agroecological Zones of Southern Ethiopia

Climate Variability and Farmers’ Perception in Southern Ethiopia

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