scholarly journals Meteorological Drought in Northwestern Escarpment of Ethiopian Rift Valley: detection seasonal and spatial trends

2021 ◽  
Author(s):  
Jemal Nasir Ahmed ◽  
Engdawork Assefa ◽  
Tesfay Zeleke ◽  
Eskinder Gidey
Keyword(s):  
Rift Valley ◽  
Meteorological Drought ◽  
Early Warning Systems ◽  
Growth Patterns ◽  
Small Scale ◽  
Ethiopian Rift ◽  
Severe Drought ◽  
The Real ◽  
Drought Impacts ◽  
Rain Season

Abstract Background: The Northwestern Escarpment of the Ethiopian Rift Valley has been frequently affected by droughts for decades. The area is among the most drought-prone and chronically food-insecure parts of the country. The study areas that include the Raya Valley livelihood Zone (RVLZ), Alagie-Offla livelihood Zone (ALOFLZ), and Tsirare Catchment Livelihood Zones (TCLZ) are amongst the most vulnerable and badly affected livelihood zones in the Northwestern Escarpment of the Ethiopian Rift Valley. Hence, this study aimed to monitor the meteorological drought conditions of the three LZs from 1983 to 2016 using the Standardized Precipitation Evapotranspiration Index (SPEI) at three months’ time scale. Both monthly Climate Hazards Group InfraRed Precipitations with Station data (CHIRPS) and Enhancing National Climate Service (ENACTS) temperature data (1983-2016) at moderate spatial resolution (i.e. 4 km-by-4km) were obtained from the National Meteorological Agency of Ethiopia. Results: This study uncovers seasonally recurring droughts that vary in severity, frequencies, and durations within and between the livelihood zones. The results indicated that severe drought occurred in all livelihoods zone of the study area from years 1983 to 1991, while ALOFLZ and TCLZ have recorded relatively higher drought severity. From 1989 to 2016, the severity and frequency of droughts were increased during the Belg (small rain) season but decreased in Kiremt (summer). In most of the study years, there have been Belg or Kiremt or both drought seasons in the study areas. The severity and frequencies of Kiremt drought in this study were higher from 1983 to 1991, better 1993 to 1998, and mildly to moderate drought from 2000-2016. As the frequencies and persistence of mild drought have increased, the intensity and precipitation amount are too small to cultivate crops and forage growth. This problem needs special considerations on the current moisture harvesting system and afforestation practices to reduce natural and human-induced drought impacts.Conclusion: Studying drought with long recorded meteorological data from a large number and uniformly distributed meteorological grids in small scale livelihood zones had great implications to identify the real trends of spatiotemporal meteorological drought. This enabled the researchers to investigate the real drought frequencies, severity, and durations in small scale areas. The study will support to improve the existing drought monitoring system and to build resilience to drought at the household level. The finding also will have a significant contribution to early warning systems, particularly at district levels. Ended, it needs to consider solutions for short and long drought impacts. The agricultural sector should consider the long-cycle crop growth patterns to reduce crop failures and forage problems.

scholarly journals Meteorological Drought in Northwestern Escarpment of Ethiopian Rift Valley: detection seasonal and spatial trends

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Jemal Nasir ◽  
Engdawork Assefa ◽  
Tesfaye Zeleke ◽  
Eskinder Gidey
Keyword(s):  
Rift Valley ◽  
Meteorological Drought ◽  
Early Warning Systems ◽  
Growth Patterns ◽  
Small Scale ◽  
Ethiopian Rift ◽  
Severe Drought ◽  
The Real ◽  
Drought Impacts ◽  
Rain Season

Abstract Background The Northwestern Escarpment of the Ethiopian Rift Valley has been frequently affected by droughts for decades. The area is among the most drought-prone and chronically food-insecure parts of the country. The study areas that include the Raya Valley livelihood Zone (RVLZ), Alagie-Offla livelihood Zone (ALOFLZ), and Tsirare Catchment Livelihood Zones (TCLZ) are amongst the most vulnerable and badly affected livelihood zones in the Northwestern Escarpment of the Ethiopian Rift Valley. Hence, this study aimed to monitor the meteorological drought conditions of the three LZs from 1983 to 2016 using the Standardized Precipitation Evapotranspiration Index (SPEI) at three months’ time scale. Both monthly Climate Hazards Group InfraRed Precipitations with Station data (CHIRPS) and Enhancing National Climate Service (ENACTS) temperature data (1983–2016) at moderate spatial resolution (i.e. 4 km-by-4 km) were obtained from the National Meteorological Agency of Ethiopia. Results This study uncovers seasonally recurring droughts that vary in severity, frequencies, and durations within and between the livelihood zones. The results indicated that severe drought occurred in all livelihoods zone of the study area from years 1983 to 1991, while ALOFLZ and TCLZ have recorded relatively higher drought severity. From 1989 to 2016, the severity and frequency of droughts were increased during the Belg (small rain) season but decreased in Kiremt (summer). In most of the study years, there have been Belg or Kiremt or both drought seasons in the study areas. The severity and frequencies of Kiremt drought in this study were higher from 1983 to 1991, better 1993–1998, and mildly to moderate drought from 2000 to 2016. As the frequencies and persistence of mild drought have increased, the intensity and precipitation amount are too small to cultivate crops and forage growth. This problem needs special considerations on the current moisture harvesting system and afforestation practices to reduce natural and human-induced drought impacts. Conclusions Studying drought with long recorded meteorological data from a large number and uniformly distributed meteorological grids in small scale livelihood zones had great implications to identify the real trends of spatiotemporal meteorological drought. This enabled the researchers to investigate the real drought frequencies, severity, and durations in small scale areas. The study will support to improve the existing drought monitoring system and to build resilience to drought at the household level. The finding also will have a significant contribution to early warning systems, particularly at district levels. Ended, it needs to consider solutions for short and long drought impacts. The agricultural sector should consider the long-cycle crop growth patterns to reduce crop failures and forage problems.

scholarly journals Meteorological Drought in Northwestern Escarpment of Ethiopian Rift Valley: Detection Seasonal and Spatial Trends

2020 ◽  
Author(s):  
Jemal Nasir Ahmed ◽  
Engdawork Assefa ◽  
Tesfay Zeleke ◽  
Eskinder Gidey
Keyword(s):  
Rift Valley ◽  
Smallholder Farmers ◽  
Meteorological Data ◽  
Meteorological Drought ◽  
Small Scale ◽  
Ethiopian Rift ◽  
Severe Drought ◽  
Economic Sectors ◽  
The Real ◽  
Rain Season

Abstract BackgroundThe Northwestern Escarpment of Ethiopian Rift Valley has been frequently affected by drought for decades in the major livelihood zones. This brought an adverse effect on the social and economic sectors because it affects significantly the smallholder farmers of the area. However, Most of these reviewed studies have limitations to show the evolutions, spatiotemporal drought frequencies, durations and severities in livelihood zone levels. Hence, the aim of this study was to monitor meteorological drought condition of the Alaje-Ofla (ALOF), Tserare Catchment (TC) and Raya Valley (RV) Livelihood Zones (LZ) from 1983 to 2016 using Standardized Precipitation Evapotranspiration Index (SPEI) at three months’ time scale. Both monthly Climate Hazards Group InfraRed Precipitations with Station data (CHIRPS) and Enhancing National Climate Service (ENACTS) temperature data (1983-2016) at moderate spatial resolution (i.e.,4 km-by-4km) were obtained from the National Meteorological Agency of Ethiopia. ResultsThis study uncovers seasonally recurring droughts that vary in severity, frequencies, and durations within as well as between the livelihood zones. The results indicated that severe drought occurred in all livelihoods zone of the study area from 1983/4 to 1991, while in the ALOFLZ and TCLZ relatively high droughts were observed. The severity and frequency of droughts were increased during the Belg (small rain) season, but decreased in Kiremt (summer) from the period 1989 to 2016. Hence, the severity of drought both on humans and livestock was severe in the area, particularly before the year 2001, but neither catastrophic drought nor food security in TCLZ and RVLZ was observed after year 2001.ConclusionStudying drought with long recorded meteorological data from a large number and uniformly distributed meteorological grids in small scale livelihood zones had great implications to identify the real trends of spatiotemporal meteorological drought. This enabled the researchers to investigate the real drought frequencies, severity, and durations in small scale areas. This study can support to improve the existing drought monitoring system and to build resilience to drought at household level.

scholarly journals Environmental Impacts of Small Scale Irrigation Schemes: Evidence from Ethiopian Rift Valley Lake Basins

2013 ◽  
Vol 63 (1) ◽  
Author(s):  
Mihret Dananto Ulsido ◽  
Ermias Alemu Demisse ◽  
Mekonene Ayana Gebul ◽  
Adunga Eneyew Bekelle
Keyword(s):  
Environmental Impacts ◽  
Rift Valley ◽  
Small Scale ◽  
Ethiopian Rift ◽  
Small Scale Irrigation ◽  
Lake Basins

scholarly journals Analysis of meteorological droughts in the Lake’s Region of Ethiopian Rift Valley using reconnaissance drought index (RDI)

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yimer Mohammed ◽  
Asnake Yimam
Keyword(s):  
Rift Valley ◽  
Drought Index ◽  
Meteorological Drought ◽  
Extreme Drought ◽  
Trend Test ◽  
Ethiopian Rift ◽  
Negative Effects ◽  
Reconnaissance Drought Index ◽  
Spatio Temporal ◽  
Temperature Records

AbstractThis study investigated the intensity, trend and spatio-temporal variability of meteorological drought in the Lakes’ Region of Ethiopian Rift Valley using monthly rainfall and maximum and minimum temperature records for the period 1986–2019. Reconnaissance Drought Index (RDI) was employed to generate the intensity of drought at 3 and 12-months timescale. Mann-Kendall trend test was used to determine the trend of the changes in the RDI time series. The spatial extent of droughts has been interpolated by inverse distance weighted (IDW) method using the spatial analyst tool of ArcGIS. Results indicated the occurrence of different intensity and trend signals across seasons and over space in the study area. A total of 33 extreme drought months were observed in all stations during summer with varying intensity (− 2.01 at Halaba to − 3.52 at Wolaita) and 168 extreme drought months at annual timescale ranging from − 2.10 at Hawassa to − 4.51 at Wolaita. The intensity of drought events observed in Wolaita in 1986 at all timescales (RDI value of − 3.19, − 3.52 and − 4.51 for spring, summer and annual respectively) were very extraordinary and devastating. Drought magnitude showed increasing signal at 6 out of 10 stations, although statistically significant at only two stations (Arsi Negelle at all timescale and Butajira at spring and annual timescale). However, the spatial patterns of drought events didn’t exhibit clear pattern rather more localized distribution and variability. The frequency of drought incidence became intense in the study area from 2008 onwards at all timescales compared to the 1990s and 2000s.The increasing tendency of drought in recent years might be the manifestation of borderless global warming. The empirical evidences showed that drought events and their negative effects are highly localized in the study area and provide useful information for local-scale planning for drought management and response.

scholarly journals Moving from drought hazard to impact forecasts

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Samuel J. Sutanto ◽  
Melati van der Weert ◽  
Niko Wanders ◽  
Veit Blauhut ◽  
Henny A. J. Van Lanen
Keyword(s):  
River Flow ◽  
Meteorological Drought ◽  
Early Warning Systems ◽  
Drought Indices ◽  
Warning Systems ◽  
Drought Management ◽  
Drought Impact ◽  
Drought Impacts ◽  
Drought Hazard ◽  
Drought Early Warning

Abstract Present-day drought early warning systems provide the end-users information on the ongoing and forecasted drought hazard (e.g. river flow deficit). However, information on the forecasted drought impacts, which is a prerequisite for drought management, is still missing. Here we present the first study assessing the feasibility of forecasting drought impacts, using machine-learning to relate forecasted hydro-meteorological drought indices to reported drought impacts. Results show that models, which were built with more than 50 months of reported drought impacts, are able to forecast drought impacts a few months ahead. This study highlights the importance of drought impact databases for developing drought impact functions. Our findings recommend that institutions that provide operational drought early warnings should not only forecast drought hazard, but also impacts after developing an impact database.

Evidence of itinerant breeding of the Red-billed Quelea Quelea quelea in the Ethiopian Rift Valley

Ibis ◽  
2008 ◽  
Vol 128 (4) ◽  
pp. 469-482 ◽  
Author(s):  
M. M. JAEGER ◽  
R. L. BRUGGERS ◽  
B. E. JOHNS ◽  
W. A. ERICKSON
Keyword(s):  
Rift Valley ◽  
Ethiopian Rift

scholarly journals Movement Around Real and Virtual Cluttered Environments

2005 ◽  
Vol 14 (5) ◽  
pp. 580-596 ◽  
Author(s):  
Simon Lessels ◽  
Roy A. Ruddle
Keyword(s):  
Real World ◽  
Search Task ◽  
Scale Space ◽  
Visual Scene ◽  
Field Of View ◽  
Small Scale ◽  
High Fidelity ◽  
Cluttered Environments ◽  
The Real ◽  
Desktop Virtual Environment

Two experiments investigated participants' ability to search for targets in a cluttered small-scale space. The first experiment was conducted in the real world with two field of view conditions (full vs. restricted), and participants found the task trivial to perform in both. The second experiment used the same search task but was conducted in a desktop virtual environment (VE), and investigated two movement interfaces and two visual scene conditions. Participants restricted to forward only movement performed the search task quicker and more efficiently (visiting fewer targets) than those who used an interface that allowed more flexible movement (forward, backward, left, right, and diagonal). Also, participants using a high fidelity visual scene performed the task significantly quicker and more efficiently than those who used a low fidelity scene. The performance differences among all the conditions decreased with practice, but the performance of the best VE group approached that of the real-world participants. These results indicate the importance of using high fidelity scenes in VEs, and suggest that the use of a simple control system is sufficient for maintaining one's spatial orientation during searching.

The Ethiopian Rift Valley lakes: chemical characteristics of a salinity-alkalinity series

Hydrobiologia ◽  
1994 ◽  
Vol 288 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Elizabeth Kebede ◽  
Zinabu G. Mariam ◽  
Ingemar Ahlgren
Keyword(s):  
Rift Valley ◽  
Ethiopian Rift ◽  
Chemical Characteristics ◽  
Rift Valley Lakes
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