scholarly journals Future climate change projection and trends under CMIP5 in Lake Tana basin, Upper Blue Nile River Basin, Ethiopia

2021 ◽  
pp. 100385
Author(s):  
Birhan Getachew ◽  
B.R. Manjunatha
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Future Climate ◽  
Future Climate Change ◽  
Nile River ◽  
Lake Tana ◽  
Blue Nile ◽  
Climate Change Projection ◽  
Blue Nile River Basin ◽  
Lake Tana Basin

scholarly journals Analyzing the future climate change of Upper Blue Nile River Basin (UBNRB) using statistical down scaling techniques

2016 ◽  
Author(s):  
Dagnenet Fenta Mekonnen ◽  
Markus Disse
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Future Climate ◽  
Maximum Temperature ◽  
Future Climate Change ◽  
Mean Annual Precipitation ◽  
Nile River ◽  
Climate Variables ◽  
Increasing Trend ◽  
Blue Nile River Basin

Abstract. Climate change is becoming one of the most arguable and threatening issues in terms of global context and their responses to environment and socio/economic drivers. Its direct impact becomes critical for water resource development and indirectly for agricultural production, environmental quality, economic development, social well-being. However, a large uncertainty between different Global Circulation Models (GCM) and downscaling methods exist that makes reliable conclusions for a sustainable water management difficult. In order to understand the future climate change of the Upper Blue Nile River Basin, two widely used statistical down scaling techniques namely LARS-WG and SDSM models were applied. Six CMIP3 GCMs for LARS-WG (CSIRO-MK3, ECHAM5-OM, MRI-CGCM2.3.2, HaDCM3, GFDL-CM2.1, CCSM3) model while HadCM3 GCM and canESM2 from CMIP5 GCMs for SDSM were used for climate change analysis. The downscaled precipitation results from the prediction of the six GCMs by LARS WG showed inconsistency and large inter model variability, two GCMs showed decreasing trend while 4 GCMs showed increasing in the range from −7.9 % to +43.7 % while the ensemble mean of the six GCM result showed increasing trend ranged from 1.0 % to 14.4 %. NCCCS GCM predicted maximum increase in mean annual precipitation. However, the projection from HadCM3 GCM is consistent with the multi-model average projection, which predicts precipitation increase from 1.7 % to 16.6 %. Conversely, the result from all GCMs showed a similar continuous increasing trend for maximum temperature (Tmax) and minimum temperature (Tmin) in all three future periods. The change for mean annual Tmax may increase from 0.4 °c to 4.3 °c whereas the change for mean annual Tmin may increase from 0.3 °c to 4.1 °c. Meanwhile, the result from SDSM showed an increasing trend for all three climate variables (precipitation, minimum and maximum temperature) from both HadCM3 and canESM2 GCMs. The relative change of mean annual precipitation range from 2.1 % to 43.8 % while the change for mean annual Tmax and Tmin may increase from 0.4 °c to 2.9 °c and from 0.3 °c to 1.6 °c respectively. The change in magnitude for precipitation is higher in RCP8.5 scenarios than others as expected. The present result illustrate that both down scaling techniques have shown comparable and good ability to simulate the current local climate variables which can be adopted for future climate change study with high confidence for the UBNRB. In order to see the comparative downscaling results from the two down scaling techniques, HadCM3 GCM of A2 scenario was used in common. The result obtained from the two down scaling models were found reasonably comparable and both approaches showed increasing trend for precipitation, Tmax and Tmin. However, the analysis of the downscaled climate data from the two techniques showed, LARS WG projected a relatively higher increase than SDSM.

scholarly journals Analysis of combined and isolated effects of land-use and land-cover changes and climate change on the upper Blue Nile River basin's streamflow

2018 ◽  
Vol 22 (12) ◽  
pp. 6187-6207 ◽  
Author(s):  
Dagnenet Fenta Mekonnen ◽  
Zheng Duan ◽  
Tom Rientjes ◽  
Markus Disse
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Nile River ◽  
Cultivated Land ◽  
Lulc Change ◽  
Blue Nile ◽  
Mk Test ◽  
Forest Coverage ◽  
Nile River Basin ◽  
Blue Nile River Basin

Abstract. Understanding responses by changes in land use and land cover (LULC) and climate over the past decades on streamflow in the upper Blue Nile River basin is important for water management and water resource planning in the Nile basin at large. This study assesses the long-term trends of rainfall and streamflow and analyses the responses of steamflow to changes in LULC and climate in the upper Blue Nile River basin. Findings of the Mann–Kendall (MK) test indicate statistically insignificant increasing trends for basin-wide annual, monthly, and long rainy-season rainfall but no trend for the daily, short rainy-season, and dry season rainfall. The Pettitt test did not detect any jump point in basin-wide rainfall series, except for daily time series rainfall. The findings of the MK test for daily, monthly, annual, and seasonal streamflow showed a statistically significant increasing trend. Landsat satellite images for 1973, 1985, 1995, and 2010 were used for LULC change-detection analysis. The LULC change-detection findings indicate increases in cultivated land and decreases in forest coverage prior to 1995, but forest area increases after 1995 with the area of cultivated land that decreased. Statistically, forest coverage changed from 17.4 % to 14.4%, by 12.2 %, and by 15.6 %, while cultivated land changed from 62.9 % to 65.6 %, by 67.5 %, and by 63.9 % from 1973 to 1985, in 1995, and in 2010, respectively. Results of hydrological modelling indicate that mean annual streamflow increased by 16.9 % between the 1970s and 2000s due to the combined effects of LULC and climate change. Findings on the effects of LULC change on only streamflow indicate that surface runoff and base flow are affected and are attributed to the 5.1 % reduction in forest coverage and a 4.6 % increase in cultivated land areas. The effects of climate change only revealed that the increased rainfall intensity and number of extreme rainfall events from 1971 to 2010 significantly affected the surface runoff and base flow. Hydrological impacts by climate change are more significant as compared to the impacts of LULC change for streamflow of the upper Blue Nile River basin.

scholarly journals Impact of climate change on the hydrology of Blue Nile basin, Ethiopia: a review

2019 ◽  
Vol 11 (4) ◽  
pp. 1539-1550 ◽  
Author(s):  
Gebre Gelete ◽  
Huseyin Gokcekus ◽  
Tagesse Gichamo
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
River Basin ◽  
Nile River ◽  
Nile Basin ◽  
Blue Nile ◽  
Impact Of Climate Change ◽  
Blue Nile Basin ◽  
Blue Nile River Basin ◽  
The Impact

Abstract Climate change alters the spacial and temporal availability of water resources by affecting the hydrologic cycle. The main objective of this paper is to review the climate change effect on the water resources of the Blue Nile River, Ethiopia. The impact of climate change on water resources is highly significant as all natural ecosystems and humans are heavily dependent on water. It alters precipitation, temperature, and streamflow of the Blue Nile river basin which is threatening the lives and livelihoods of people and life-supporting systems. Rainfall within the Blue Nile river basin is highly erratic and seasonal due to it being located in the inter-tropical convergent zone. The temperature and sediment load are shown to increase in the future while the rainfall and streamflow are decreasing. The Blue Nile basin is characterized by highly erosive rainfall, erodible soil, and shrinking forest cover. Therefore, mitigation and adaptation measures should be applied by considering these characteristics of the basin. Watershed management methods like afforestation and water conservation are recommended to reduce the impact on the Blue Nile basin.

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