CMIP5 model simulations of Ethiopian Kiremt-season precipitation: current climate and future changes

Abstract

over central Highlands and northern Great Rift Valley in Ethiopia, but a decrease in precipitation over the southern part of the country. Such a dipole pattern is attributable to the intensification of the North Atlantic subtropical high (NASH) in a warmer climate, which influences Ethiopian Kiremt-season precipitation mainly by modulating atmospheric vertical motion. Diagnosis of the omega equation demonstrates that an intensified NASH increases (decreases) the advection of warm air and positive vorticity into the central Highlands and northern Great Rift Valley (southern part of the country), enhancing upward motion over the northern Rift Valley but decreasing elsewhere. Under the RCP 4.5 scenario, the high-resolution models project an intensification of the NASH by 15 (3 × 10 5 m 2 s −2 ) geopotential meters (stream function) at the 850-hPa level, contributing to the projected precipitation change over Ethiopia. The influence of the NASH on Kiremtseason precipitation becomes more evident in the future due to the offsetting effects of two other major circulation systems: the East African Low-level Jet (EALLJ) and the Tropical Easterly Jet (TEJ). The high-resolution models project a strengthening of the EALLJ, but a weakening of the TEJ. Future changes in the EALLJ and TEJ will drive this precipitation system in opposite directions, leading to small or no net changes in precipitation in Ethiopia.

Evaluating the CMIP5 ensemble in Ethiopia: Creating a reduced ensemble for rainfall and temperature in Northwest Ethiopia and the Awash basin

“…Beyond this, the relationship between Ethiopian rainfall and regional SSTs needs to be better understood. This would build upon previous work by Degefu et al (2017), Li et al (2016) and Diro et al (2011) but incorporate more models and focus on understanding the dynamics of biases in the onset season along with as the main rainy season. The interactions with surrounding African climate regimes, such as the Sahel band, and East and Central Africa have also been alluded to (Viste et al, 2013), but requires further investigation with relation to GCMs.…”

“…Finally, the effects of some of the large scale overturning circulations on Ethiopian rainfall may highlight some potential causes of bias in models. In particular investigating the impact of the ability of models to capture the Asian Monsoon circulation on rainfall in Ethiopia from June-September building on the connection between the Tropical Easterly Jet and Ethiopian rainfall shown by Li et al (2016) and on the work of Sperber et al (2013) who did a detailed analysis of the skill of CMIP3/5 models in reproducing the Asian Monsoon.…”

“…However the ability of GCMs to reproduce the historical climate of Ethiopia has not been widely studied, possibly because of the unique climate characteristics of the country such as the complex rainfall seasonality which render it distinct from East Africa to the south, and the Sahel to the west. The model studies that have been done, focus on a particular rainy season alone (Li et al ., ), or a smaller sub‐set of models (Diro et al ., ; Degefu et al ., ). Establishing the fidelity of global climate models in different regions of Ethiopia, and for different seasons could yield strategic information about why models can or cannot simulate the climate, and teleconnections.…”

Study on the characteristics of future precipitation in response to external changes over arid and humid basins

“…In order to facilitate the adaptive management to the climate change at different areas, it’s critical to investigate the implications of climate changes and estimate its temporal-spatial variation patterns 6 , 35 , 36 . Therefore the characteristics and response degree of future precipitation in typical watersheds to climate change should be analyzed.…”

Prevalence and Associated Factors of Agricultural Technology Adoption and Teff Productivity in Basso Liben District, East Gojjame Zone, North west Ethiopia

“…Amhara regional state was 1.261 ton/hectare (25), 1.2 ton/hectare (26), 1.69 ton/hectare, Oromia other study conducted in different area could be different technology adoption, temperature(28), rainfall(29), climate(30), soil quality(31) and amount of nitrogen fertilizers used in growing the crop. The amount of DAP (kilogram) used in the previous year average of 72.44 kg/hectare.…”