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2 results on '"Gashaw Bimrew Tarkegn"'

1. Changes in the Seasonality of Ethiopian Highlands Climate and Implications for Crop Growth

Author

Gashaw Bimrew Tarkegn and Mark R. Jury

Subjects
Ethiopia highlands, seasonal climate, crop impacts, Meteorology. Climatology, QC851-999
Abstract

Rain-fed agriculture in North-West (NW) Ethiopia is seasonally modulated, and our objective is to isolate past and future trends that influence crop growth. Statistical methods are applied to gauge-interpolated, reanalysis, and satellite data to evaluate changes in the annual cycle and long-term trends. The June to September wet season has lengthened due to the earlier arrival and later departure of rains. Meteorological composites relate this spreading to local southerly winds and a dry-south/wet-north humidity dipole. At the regional scale, an axis of convection over the Rift Valley (35E) is formed by westerly waves on 15S and an anticyclone over Asia 30N. Coupled Model Intercomparsion Project (CMIP5) Hadley2 data assimilated by the Inter-Sectoral Impact Model Intercomparision Project (ISIMIP) hydrological models are used to evaluate projected soil moisture and potential evaporation over the 21st century. May and October soil moisture is predicted to increase in the future, but trends are weak. In contrast, the potential evaporation is rising and may put stress on the land and water resources. A lengthening of the growing season could benefit crop yields across the NW Ethiopian highlands.

Published
2020
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2. Evaluation of Past and Future Climate Trends under CMIP6 Scenarios for the UBNB (Abay), Ethiopia

Author

Gashaw Bimrew Tarkegn, Seifu A. Tilahun, Addis A. Alaminie, Solomon A. Legesse, Mark R. Jury, and Fasikaw A. Zimale

Subjects
010504 meteorology & atmospheric sciences, Nile basin, Geography, Planning and Development, 0207 environmental engineering, 02 engineering and technology, Aquatic Science, Structural basin, precipitation, climate projection, 01 natural sciences, Biochemistry, Upper Blue Nile (Abay), Precipitation, 020701 environmental engineering, TD201-500, CMIP6, 0105 earth and related environmental sciences, Water Science and Technology, Maximum temperature, Water supply for domestic and industrial purposes, temperature, Hydraulic engineering, Future climate, Trend analysis, Climatology, Environmental science, Climate model, TC1-978, Quantile
Abstract

Climate predictions using recent and high-resolution climate models are becoming important for effective decision-making and for designing appropriate climate change adaptation and mitigation strategies. Due to highly variable climate and data scarcity of the upper Blue Nile Basin, previous studies did not detect specific unified trends. This study discusses, the past and future climate projections under CMIP6-SSPs scenarios for the basin. For the models’ validation and selection, reanalysis data were used after comparing with area-averaged ground observational data. Quantile mapping systematic bias correction and Mann–Kendall trend test were applied to evaluate the trends of selected CMIP6 models during the 21st century. Results revealed that, ERA5 for temperature and GPCC for precipitation have best agreement with the basin observational data, MRI-ESM2-0 for temperature and BCC-CSM-2MR for precipitation were selected based on their highest performance. The MRI-ESM2-0 mean annual maximum temperature for the near (long)-term period shows an increase of 1.1 (1.5) °C, 1.3 (2.2) °C, 1.2 (2.8) °C, and 1.5 (3.8) °C under the four SSPs. On the other hand, the BCC-CSM-2MR precipitation projections show slightly (statistically insignificant) increasing trend for the near (long)-term periods by 5.9 (6.1)%, 12.8 (13.7)%, 9.5 (9.1)%, and 17.1(17.7)% under four SSPs scenarios.

Published
2021
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