Understanding traditional agro-ecosystem dynamics in response to systematic transition processes and rainfall variability patterns at watershed-scale in Southern Ethiopia

2022 ◽  
Vol 327 ◽  
pp. 107832
Author(s):  
Berhan Gessesse ◽  
Birhane Gebrehiwot Tesfamariam ◽  
Farid Melgani
Keyword(s):  
Rainfall Variability ◽  
Ecosystem Dynamics ◽  
Southern Ethiopia ◽  
Watershed Scale ◽  
Transition Processes

scholarly journals Predicting East African spring droughts using Pacific and Indian Ocean sea surface temperature indices

2014 ◽  
Vol 11 (3) ◽  
pp. 3111-3136 ◽  
Author(s):  
C. Funk ◽  
A. Hoell ◽  
S. Shukla ◽  
I. Bladé ◽  
B. Liebmann ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Rainfall Variability ◽  
Sea Surface ◽  
Southern Ethiopia ◽  
East African ◽  
Central Pacific ◽  
Boreal Spring ◽  
Central Indian Ocean

Abstract. In southern Ethiopia, Eastern Kenya, and southern Somalia, poor boreal spring rains in 1999, 2000, 2004, 2007, 2008, 2009, and 2011 contributed to severe food insecurity and high levels of malnutrition. Predicting rainfall deficits in this region on seasonal and decadal time frames can help decision makers implement disaster risk reduction measures while guiding climate-smart adaptation and agricultural development. Building on recent research that links more frequent droughts in that region to a stronger Walker Circulation, warming in the Indo-Pacific warm pool, and an increased western Pacific sea surface temperature (SST) gradient, we show that the two dominant modes of East African boreal spring rainfall variability are tied, respectively, to western-central Pacific and central Indian Ocean SST. Variations in these rainfall modes can be predicted using two previously defined SST indices – the West Pacific Gradient (WPG) and Central Indian Ocean index (CIO), with the WPG and CIO being used, respectively, to predict the first and second rainfall modes. These simple indices can be used in concert with more sophisticated coupled modeling systems and land surface data assimilations to help inform early warning and guide climate outlooks.

scholarly journals High-Resolution Monthly Rainfall Database for Ethiopia: Homogenization, Reconstruction, and Gridding

2012 ◽  
Vol 25 (24) ◽  
pp. 8422-8443 ◽  
Author(s):  
G. Mengistu Tsidu
Keyword(s):  
Harmonic Analysis ◽  
Missing Values ◽  
Rainfall Variability ◽  
Singular Spectrum Analysis ◽  
Monthly Rainfall ◽  
Climatic Research Unit ◽  
Southern Ethiopia ◽  
Self Organizing Map ◽  
Global Datasets ◽  
Self Organizing

Abstract Recent heightened concern regarding possible consequences of anthropogenically induced global warming has spurred analyses of data aimed at detection of climate change and more thorough characterization of the natural climate variability. However, there is greater concern regarding the extent and especially quality of the historical climate data. In this paper, rainfall records of 233 gauge stations over Ethiopia for the 1978–2007 period are employed in an analysis that involves homogenization, reconstruction, and gridding onto a regular 0.5° × 0.5° resolution grid. Inhomogeneity is detected and adjusted based on quantile matching. The regularized expectation-maximization and multichannel singular spectrum analysis algorithms are then utilized for imputation of missing values, and the latter has been determined to have a marginal advantage. Ordinary kriging is used to create a gridded monthly rainfall dataset. The spatial and temporal coherence of this dataset are assessed using harmonic analysis, self-organizing maps, and intercomparison with global datasets. The self-organizing map delineates Ethiopia into nine homogeneous rainfall regimes, which is consistent with seasonal and interannual rainfall variations. The harmonic analysis of the dataset reveals that the annual mode accounts for 55%–85% of the seasonal rainfall variability over western Ethiopia while the semiannual mode accounts for up to 40% over southern Ethiopia. The dataset is also intercompared with Global Precipitation Climatology Project (GPCP), Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP), Climatic Research Unit time series version 3 (CRUTS3.0), Tropical Rainfall Measuring Mission (TRMM), and interim ECMWF Re-Analysis (ERA-Interim) rainfall. The correlation of the dataset with global datasets ranges from 0.52 to 0.95 over sparse to dense rain gauge regions. The GPCP rainfall has a small bias and good correlation with the new dataset whereas TRMM and ERA-Interim have relatively large dry and wet biases, respectively.

scholarly journals Evaluating Climate Change Impact of Rainfed Maize Production Yield in Southern Ethiopia

2022 ◽  
Author(s):  
Kinde Negessa Disasa ◽  
Haofang Yan
Keyword(s):  
Climate Change ◽  
Time Horizon ◽  
Crop Production ◽  
Rainfall Variability ◽  
Maximum Temperature ◽  
Yield Response ◽  
Southern Ethiopia ◽  
Maize Production ◽  
Mitigation And Adaptation ◽  
Study Results

Abstract A developing country like Ethiopia suffers a lot from the effects of climate change due to its limited economic capability to build irrigation projects to combat climate change's impact on crop production. This study evaluates climate change's impact on rainfed maize production in the Southern part of Ethiopia. AquaCrop, developed by FAO that simulates the crop yield response to water deficit conditions, is employed to assess potential rainfed maize production in the study area with and without climate change. The Stochastic weather generators model LARS-WG of the latest version is used to simulate local-scale level climate variables based on low-resolution GCM outputs. The expected monthly percentage change of rainfall during these two-time horizons (2040 and 2060) ranges from -23.18 to 20.23% and -14.8 to 36.66 respectively. Moreover, the monthly mean of the minimum and maximum temperature are estimated to increase in the range of 1.296 0C to 2.192 0C and 0.98 0C to 1.84 0C for the first time horizon (2031-2050) and from 1.860C to 3.40C and 1.560C to 3.180C in the second time horizon (2051-2070), respectively. Maize yields are expected to increase with the range of 4.13–7% and 6.36–9.32% for the respective time horizon in the study area provided that all other parameters were kept the same. In conclusion, the study results suggest that rainfed maize yield responds positively to climate change if all field management, soil fertility, and crop variety improve were kept the same to baseline; but since there is intermodal rainfall variability among the seasons planting date should be scheduled well to combat water stress on crops. The authors believe that this study is very likely important for regional development agents (DA) and policymakers to cope up with the climate change phenomenon and take some mitigation and adaptation strategies.

scholarly journals Analysis of Climate Variability and Trends in Southern Ethiopia

Climate ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 96
Author(s):  
Abrham Belay ◽  
Teferi Demissie ◽  
John W. Recha ◽  
Christopher Oludhe ◽  
Philip M. Osano ◽  
...  
Keyword(s):  
Rainfall Variability ◽  
Rate Of Change ◽  
Mitigation Strategies ◽  
Annual Rainfall ◽  
Southern Ethiopia ◽  
Drought Indices ◽  
Trend Test ◽  
Rainfall Trends ◽  
Slope Estimator ◽  
Normal Rainfall

This study investigated the trends and variability of seasonal and annual rainfall and temperature data over southern Ethiopia using time series analysis for the period 1983–2016. Standard Anomaly Index (SAI), Coefficient of Variation (CV), Precipitations Concentration Index (PCI), and Standard Precipitation Index (SPI) were used to examine rainfall variability and develop drought indices over southern Ethiopia. Temporal changes of rainfall trends over the study period were detected using Mann Kendall (MK) trend test and Sen’s slope estimator. The results showed that the region experienced considerable rainfall variability and change that resulted in extended periods of drought and flood events within the study period. Results from SAI and SPI indicated an inter-annual rainfall variability with the proportions of years with below and above normal rainfall being estimated at 56% and 44% respectively. Results from the Mann Kendall trend test indicated an increasing trend of annual rainfall, Kiremt (summer) and Bega (dry) seasons whereas the Belg (spring) season rainfall showed a significant decreasing trend (p < 0.05). The annual rate of change for mean, maximum and minimum temperatures was found to be 0.042 °C, 0.027 °C, and 0.056 °C respectively. The findings from this study can be used by decision-makers in taking appropriate measures and interventions to avert the risks posed by changes in rainfall and temperature variability including extremes in order to enhance community adaptation and mitigation strategies in southern Ethiopia.

scholarly journals Expanding Rubber Plantations in Southern China: Evidence for Hydrological Impacts

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 651 ◽  
Author(s):  
Xing Ma ◽  
Guillaume Lacombe ◽  
Rhett Harrison ◽  
Jianchu Xu ◽  
Meine van Noordwijk
Keyword(s):  
Southern China ◽  
Rainfall Variability ◽  
Rubber Tree ◽  
Dry Season ◽  
Base Flow ◽  
Balance Model ◽  
Tree Plantations ◽  
Watershed Scale ◽  
Rubber Plantations ◽  
Local Water

While there is increasing evidence concerning the detrimental effects of expanding rubber plantations on biodiversity and local water balances, their implications on regional hydrology remain uncertain. We studied a mesoscale watershed (100 km2) in the Xishuangbanna prefecture, Yunnan Province, China. The influence of land-cover change on streamflow recorded since 1992 was isolated from that of rainfall variability using cross-simulation matrices produced with the monthly lumped conceptual water balance model GR2M. Our results indicate a statistically significant reduction in wet and dry season streamflow from 1992 to 2002, followed by an insignificant increase until 2006. Analysis of satellite images from 1992, 2002, 2007, and 2010 shows a gradual increase in the areal percentage of rubber tree plantations at the watershed scale. However, there were marked heterogeneities in land conversions (between forest, farmland, grassland, and rubber tree plantations), and in their distribution across elevations and slopes, among the studied periods. Possible effects of this heterogeneity on hydrological processes, controlled mainly by infiltration and evapotranspiration, are discussed in light of the hydrological changes observed over the study period. We suggest pathways to improve the eco-hydrological functionalities of rubber tree plantations, particularly those enhancing dry-season base flow, and recommend how to monitor them.

DEALING WITH CLIMATE-RELATED RISKS: SOME PIONEERING IDEAS FOR ENHANCED PASTORAL RISK MANAGEMENT IN AFRICA

2011 ◽  
Vol 47 (2) ◽  
pp. 375-393 ◽  
Author(s):  
ROBERT OUMA ◽  
ANDREW MUDE ◽  
JEANNETTE VAN DE STEEG
Keyword(s):  
Risk Management ◽  
Rainfall Variability ◽  
Future Climate Change ◽  
Southern Ethiopia ◽  
Pastoral Systems ◽  
Pilot Studies ◽  
Development Interventions ◽  
External Pressures ◽  
Wide Range ◽  
Management Approaches

SUMMARYThis paper makes the case for innovative risk management approaches in pastoral settings, which may include adjustments to the traditionally practiced approaches that have become progressively less effective. We use recent data from studies in Kenya and southern Ethiopia to confirm that traditional pastoral risk management approaches are increasingly futile against increasing external pressures, seasonal rainfall variability and future climate change. Some pioneering approaches and ideas, with potentially wider application to African pastoral settings, appear to offer greater hope; these include pilot studies designed to demonstrate the efficacy of index-based risk transfer products in pastoral systems, improvements in the management of food insecurity response for pastoralists and the recasting of development interventions as risk management. The International Livestock Research Institute, in collaboration with a wide range of partners, is currently testing these ideas.

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