scholarly journals Using seasonal rainfall clusters to explain the interannual variability of the rain belt over the Greater Horn of Africa

2020 ◽  
Author(s):  
Larisa S. Seregina ◽  
Andreas H. Fink ◽  
Roderick Linden ◽  
Chris Funk ◽  
Joaquim G. Pinto
Keyword(s):  
Interannual Variability ◽  
Seasonal Rainfall ◽  
Horn Of Africa ◽  
Rain Belt ◽  
Greater Horn Of Africa

scholarly journals Projected effects of 1.5 °C and 2 °C global warming levels on the intra-seasonal rainfall characteristics over the Greater Horn of Africa

2020 ◽  
Vol 15 (3) ◽  
pp. 034037 ◽  
Author(s):  
Masilin Gudoshava ◽  
Herbert O Misiani ◽  
Zewdu T Segele ◽  
Suman Jain ◽  
Jully O Ouma ◽  
...  
Keyword(s):  
Global Warming ◽  
Seasonal Rainfall ◽  
Horn Of Africa ◽  
Rainfall Characteristics ◽  
Greater Horn Of Africa

Improving multimodel medium range forecasts over the Greater Horn of Africa using the FSU superensemble

2016 ◽  
Vol 128 (4) ◽  
pp. 441-451 ◽  
Author(s):  
O. Kipkogei ◽  
A. Bhardwaj ◽  
V. Kumar ◽  
L. A. Ogallo ◽  
F. J. Opijah ◽  
...  
Keyword(s):  
Horn Of Africa ◽  
Medium Range ◽  
Greater Horn Of Africa ◽  
Range Forecasts

Downscaling of a seasonal ensemble forecast at the convection-permitting resolution over the Horn of Africa using the WRF model

2021 ◽  
Author(s):  
Paolo Mori ◽  
Thomas Schwitalla ◽  
Markos Ware ◽  
Kirsten Warrach-Sagi ◽  
Volker Wulfmeyer
Keyword(s):  
Boundary Conditions ◽  
Wrf Model ◽  
Added Value ◽  
Limited Area ◽  
Horn Of Africa ◽  
Ensemble Spread ◽  
Rain Belt ◽  
Physics Ensemble ◽  
June July ◽  
The Right

<p>Studies have shown the benefits of convection-permitting downscaling at the seasonal scale using limited-area models. To evaluate the performance with real forecasts as boundary conditions, four members of the SEAS5 global ensemble were dynamically downscaled over Ethiopia during June, July, and August 2018 at a 3-km resolution. We used a multi‐physics ensemble based on the WRF model to compare the effects of boundary conditions and physics <span><span>parametrization</span></span> producing 16 ensemble members. With ECMWF analyses as a reference, SEAS5 averaged to a +0.17°C bias over Ethiopia whereas WRF resulted in +1.14°C. With respect to precipitation, the WRF model simulated 264 mm compared to 248 mm for SEAS5 and 236 mm for GPM-IMERG. The maximum northward extension of the tropical rain belt decreased by about 2° in both models. Downscaling enhanced the ensemble spread in precipitation by 60% on average, correcting the SEAS5 underdispersion. The WRF ensemble spread over Ethiopia was mostly generated by the perturbed boundary conditions, as their effect is often 50% larger than the physics‐induced variability. The results indicate that boundary condition perturbations are necessary, although not always sufficient, to generate the right amount of ensemble spread in a limited-area model with complex topography. The next step is to use specific methods to calculate the added value provided by the downscaling.</p>

scholarly journals Seasonal Drought in the Greater Horn of Africa and Its Recent Increase during the March–May Long Rains

2014 ◽  
Vol 27 (21) ◽  
pp. 7953-7975 ◽  
Author(s):  
Bradfield Lyon
Keyword(s):  
Atmospheric Circulation ◽  
Climate Model ◽  
Southern Oscillation ◽  
Meteorological Drought ◽  
Tropical Pacific ◽  
Horn Of Africa ◽  
New Findings ◽  
Climate Model Simulations ◽  
Greater Horn Of Africa ◽  
The Tropical Pacific

Abstract This paper provides a review of atmospheric circulation and sea surface temperature (SST) conditions that are associated with meteorological drought on the seasonal time scale in the Greater Horn of Africa (the region 10°S–15°N, 30°–52°E). New findings regarding a post-1998 increase in drought frequency during the March–May (MAM) “long rains” are also reported. The period 1950–2010 is emphasized, although rainfall and SST data from 1901–2010 are used to place the recent long rains decline in a multidecadal context. For the latter case, climate model simulations and isolated basin SST experiments are also utilized. Climatologically, rainfall exhibits a unimodal June–August (JJA) maximum in west-central Ethiopia with a generally bimodal [MAM and October–December (OND) maxima] distribution in locations to the south and east. Emphasis will be on these three seasons. SST anomalies in the tropical Pacific and Indian Oceans show the strongest association with drought during OND in locations having a bimodal annual cycle, with weaker associations during MAM. The influence of the El Niño–Southern Oscillation (ENSO) phenomenon critically depends on its ability to affect SSTs outside the Pacific. Salient features of the anomalous atmospheric circulation during drought events in different locations and seasons are discussed. The post-1998 decline in the long rains is found to be driven strongly (although not necessarily exclusively) by natural multidecadal variability in the tropical Pacific rather than anthropogenic climate change. This conclusion is supported by observational analyses and climate model experiments, which are presented.

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