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.

Land cover changes as impacted by spatio-temporal rainfall variability along the Ethiopian Rift Valley escarpment

2016 ◽  
Vol 17 (2) ◽  
pp. 451-463 ◽  
Author(s):  
Sofie Annys ◽  
Biadgilgn Demissie ◽  
Amanuel Zenebe Abraha ◽  
Miro Jacob ◽  
Jan Nyssen
Keyword(s):  
Land Cover ◽  
Rift Valley ◽  
Rainfall Variability ◽  
Ethiopian Rift ◽  
Land Cover Changes ◽  
Spatio Temporal

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 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 Spatio‐temporal characteristics of meteorological drought under changing climate in semi‐arid region of northern Ethiopia

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Biniyam Yisehak ◽  
Henok Shiferaw ◽  
Haftu Abrha ◽  
Amdom Gebremedhin ◽  
Haftom Hagos ◽  
...  
Keyword(s):  
Climate Change ◽  
Meteorological Drought ◽  
Extreme Drought ◽  
Maximum Temperature ◽  
Northern Ethiopia ◽  
Temporal Characteristics ◽  
Changing Climate ◽  
Annual Minimum Temperature ◽  
Rcp 8.5 ◽  
Spatio Temporal

Abstract Background Below-normal availability of water for a considerable period of time induces occurrence of drought. This paper investigates the Spatio-temporal characteristics of meteorological drought under changing climate. The climate change was analyzed using delta based statistical downscaling approach of RCP 4.5 and RCP 8.5 in R software packages. The meteorological drought was assessed using the Reconnaissance Drought Index (RDI). Results The result of climate change projections showed that the average annual minimum temperature will be increased by about 0.8–2.9 °C. The mean annual maximum temperature will be also increased by 0.9–3.75 °C. The rainfall projection generally showed an increasing trend, it exhibited an average annual increase of 3.5–13.4 % over the study area. The projected drought events reached its maximum severity indicated extreme drought in the years 2043, 2044, 2073, and 2074. The RDI value shows drought will occurred after 1–6 and 2–7 years under RCP 4.5 and RCP 8.5 emission scenarios respectively over the study area. Almost more than 72 % of the current and future spatial coverage of drought in the study area will be affected by extreme drought, 22.3 % severely and 5.57 % also moderate drought. Conclusions Therefore, the study helps to provide useful information for policy decision makers to implement different adaptation and mitigation measures of drought in the region.

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