Using seasonal forecast information to strengthen resilience and improve food security in Niger River Basin

2020 ◽  
Author(s):  
Bernard Minoungou ◽  
Jafet Andersson ◽  
Abdou Ali ◽  
Mohamed Hamatan
Keyword(s):  
Food Security ◽  
West Africa ◽  
River Basin ◽  
Rainy Season ◽  
Hydrological Model ◽  
Seasonal Forecast ◽  
Reference Period ◽  
Seasonal Forecasts ◽  
Niger River

<p>The rainy season occupies a central place in socio-economic activities in the Sahelian regions, as more than 80% of the population lives on agriculture and livestock. However, extreme hydroclimatic events such as droughts and floods affect these activities. Efforts made in recent years in the production of hydroclimatic information to enhance the resilience of populations have become insufficient, given the variability and climate change.</p><p>In this context, we have conducted a study on improving the quality of seasonal forecast information to strengthen the resilience and improve the food security in West Africa, especially on the Niger River Basin. We used seasonal climate forecasts and the HYPE hydrological model to predict some characteristics of the rainy season in West Africa. The ECMWF seasonal forecast ensemble (system 5) from 1993 to 2015 (hindcast) and 2018 (forecast), available in the Climate Data Store (CDS) catalogue were used. The climatic variables considered are daily precipitation, mean and extreme temperatures (minimum and maximum) at the seasonal scale. The main objective was to assess the ability of the HYPE hydrological model, developed by Swedish Meteorological and Hydrological Institue, to predict runoff over the historical period and to produce hydrological seasonal forecasts for next years.</p><p>The main season’s characteristics produced are: (i) cumulative rainfall map for the rainy season (May to November), (ii) the rainfall situation of the season (above, near or below normal considering 1993-2015 as reference period), (iii) hydrological situation of the season (above, near or below normal considering 1993-2015 as reference period), (v) graph of the mean seasonal streamflow over the Niger Basin compared to the reference period (1993-2015).</p><p>The predictability of 2018 hydrological seasonal products were assessed and the results are promising. The main challenges we faced were the initialisation of the model, the bias correction (the reference data to be considered and the appropriate method). Further research on these topics should continue to improve the quality of results.</p>

scholarly journals A numerical modelling study of the hydroclimatology of the Niger River Basin, West Africa

2015 ◽  
Vol 61 (1) ◽  
pp. 94-106 ◽  
Author(s):  
Philip G. Oguntunde ◽  
Babatunde J. Abiodun ◽  
Gunnar Lischeid
Keyword(s):  
Numerical Modelling ◽  
West Africa ◽  
River Basin ◽  
Niger River ◽  
Modelling Study

Impact of bias correction techniques on an ensemble of seasonal discharge forecast for the Danube upstream of Vienna

2021 ◽  
Author(s):  
Ignacio Martin Santos ◽  
Mathew Herrnegger ◽  
Hubert Holzmann
Keyword(s):  
Bias Correction ◽  
Hydrological Model ◽  
Systematic Errors ◽  
Seasonal Forecasts ◽  
Scaling Factors ◽  
Quantile Mapping ◽  
Forecasting System ◽  
Mapping Techniques ◽  
Seasonal Discharge

<p>The skill of seasonal hydro-meteorological forecasts with a lead time of up to six months is currently limited, since they frequently exhibit random but also systematic errors. Bias correction algorithms can be applied and provide an effective approach in removing historical biases relative to observations. Systematic errors in hydrology model outputs can be consequence of different sources: i) errors in meteorological data used as input data, ii) errors in the hydrological model response to climate forcings, iii) unknown/unobservable internal states and iv) errors in the model parameterizations, also due to unresolved subgrid scale variability.</p><p>Normally, bias correction techniques are used to correct meteorological, e.g. precipitation data, provided by climate models. Only few studies are available applying these techniques to hydrological model outputs. Standard bias correction techniques used in literature can be classified into scaling-, and distributional-based methods. The former consists of using multiplicative or additive scaling factors to correct the modeled simulations, while the later methods are quantile mapping techniques that fit the distribution of the simulation to fit to the observations. In this study, the impact of different bias correction techniques on the seasonal discharge forecasts skill is assessed.</p><p>As a case study, a seasonal discharge forecasting system developed for the Danube basin upstream of Vienna, is used. The studied basin covers an area of around 100 000 km<sup>2</sup> and is subdivided in 65 subbasins, 55 of them gauged with a long historical record of observed discharge. The forecast system uses the calibrated hydrological model, COSERO, which is fed with an ensemble of seasonal temperature and precipitation forecasts. The output of the model provides an ensemble of seasonal discharge forecasts for each of the (gauged) subbasins. Seasonal meteorological forecasts for the past (hindcast), together with historical discharge observations, allow to assess the quality of the seasonal discharge forecasting system, also including the effects of different bias correction methods. The corrections applied to the discharge simulations allow to eliminate potential systematic errors between the modeled and observed values.</p><p>Our findings generally suggest that the quality of the seasonal forecasts improve when applying bias correction. Compared to simpler methods, which use additive or multiplicative scaling factors, quantile mapping techniques tend to be more appropriate in removing errors in the ensemble seasonal forecasts.</p>

scholarly journals Process refinements improve a hydrological model concept applied to the Niger River basin

2017 ◽  
Vol 31 (25) ◽  
pp. 4540-4554 ◽  
Author(s):  
Jafet C.M. Andersson ◽  
Berit Arheimer ◽  
Farid Traoré ◽  
David Gustafsson ◽  
Abdou Ali
Keyword(s):  
River Basin ◽  
Hydrological Model ◽  
Model Concept ◽  
Niger River

Evaluation of recent hydro-climatic changes in four tributaries of the Niger River Basin (West Africa)

2016 ◽  
Vol 62 (5) ◽  
pp. 715-728 ◽  
Author(s):  
Djigbo Félicien Badou ◽  
Evison Kapangaziwiri ◽  
Bernd Diekkrüger ◽  
Jean Hounkpè ◽  
Abel Afouda
Keyword(s):  
West Africa ◽  
River Basin ◽  
Climatic Changes ◽  
Niger River

scholarly journals Development of seasonal climate outlooks for agriculture in Finland

2020 ◽  
Vol 17 ◽  
pp. 269-277
Author(s):  
Andrea Vajda ◽  
Otto Hyvärinen
Keyword(s):  
Management Practices ◽  
Seasonal Forecast ◽  
Lead Times ◽  
Seasonal Forecasts ◽  
Climate Services ◽  
Seasonal Climate ◽  
Crop Choice ◽  
Temperature Forecast ◽  
Dry Conditions

Abstract. Seasonal climate forecast products offer useful information for farmers supporting them in planning and making decisions in their management practices, such as crop choice, planting and harvesting time, and water management. Driven by the need of stakeholders for tailored seasonal forecast products, our goal was to assess the applicability of seasonal forecast outputs in agriculture and to develop and pilot with stakeholders a set of seasonal climate outlooks for this sector in Finland. Finnish end users were involved in both the design and testing of the outlooks during the first pilot season of 2019. The seasonal climate outlooks were developed using the SEAS5 seasonal forecast system provided by ECMWF. To improve the prediction skill of the seasonal forecast data, several bias adjustment approaches were evaluated. The tested methods increased the quality of temperature forecast, but no suitable approach was found for eliminating the biases from precipitation data. Besides the widely applied indices, such as mean temperature, growing degree days, cold spell duration, total precipitation and dry conditions, new sector-oriented indices (such as progress of growing season) have been implemented and issued for various lead times (up to 3 months). The first result of forecast evaluation, the development of seasonal forecast indices and the first pilot season of May–October 2019 are presented. We found that the temperature-based outlooks performed well, with better performance skills for short lead times, providing useful information for the farmers in activity management. Precipitation indices had poor skills for each forecasted month, and further research is needed for improving the quality of forecast for Finland. The farmers who have tested the seasonal climate outlooks considered those beneficial and valuable, helping them in planning their activities. Following the first pilot season, further research and implementation work took place to improve our understanding of the skill of seasonal forecasts and increase the quality of tailored seasonal climate services.

Modelling the impacts of reforestation on the projected hydroclimatology of Niger River Basin, West Africa

Ecohydrology ◽  
2012 ◽  
Vol 7 (1) ◽  
pp. 163-176 ◽  
Author(s):  
Philip G. Oguntunde ◽  
Babatunde J. Abiodun ◽  
Gunnar Lischeid ◽  
Christoph Merz
Keyword(s):  
West Africa ◽  
River Basin ◽  
Niger River

Modelling blue and green water availability under climate change in the Beninese Basin of the Niger River Basin, West Africa

2018 ◽  
Vol 32 (16) ◽  
pp. 2526-2542 ◽  
Author(s):  
Djigbo Félicien Badou ◽  
Bernd Diekkrüger ◽  
Evison Kapangaziwiri ◽  
Mamadou L. Mbaye ◽  
Yacouba Yira ◽  
...  
Keyword(s):  
Climate Change ◽  
West Africa ◽  
River Basin ◽  
Water Availability ◽  
Green Water ◽  
Niger River

The Hydrometeorology of Niger River Basin

2013 ◽  
Vol 824 ◽  
pp. 613-629 ◽  
Author(s):  
Chucks Okoli
Keyword(s):  
Temperature Gradient ◽  
West Africa ◽  
Surface Temperature ◽  
Southern Hemisphere ◽  
River Basin ◽  
Northern Hemisphere ◽  
River Flow ◽  
Seasonal Evolution ◽  
Niger River ◽  
Surface Temperature Gradient

This paper examines the mean annual cycle of rainfall and general circulation features over the Niger River Basin consisting of mainly West Africa and Central Africa regions. Rainfall is examined using a 1400-station archive compiled by earlier workers. Other circulation features are examined using the NCEPNCAR reanalysis dataset. Important features of the reanalysis zonal wind field are shown to compare well with the seasonal evolution described by the radiosonde observations. In addition to the well-known African easterly jet (AEJ) of the Northern Hemisphere, the seasonal evolution of its Southern Hemisphere counterpart is also described. Thermal wind calculations show that although the southern jet is weaker, its existence is also due to a local reversal of the surface temperature gradient. In the upper troposphere, a strong semiannual cycle is shown in the 200-mb easterlies and a feature like the tropical easterly jet (TEJ) is evident south of the equator in January and February. The paper describes the movement of the rainbelt between central and West Africa. An asymmetry in the northward and southward migration of the rainbelt is evident. The paper discusses the influence that the jets may have on rainfall and possible feedback effects of rainfall on the jets. Evidence suggests that the midtropospheric jets influence the development of the rainy season, but also that the rainfall affects the surface temperature gradient and in turn the jets. In the Northern Hemisphere, east of 200E, the axis of the TEJ is located so that it may promote convection by increasing upper-level divergence. However, west of 100E and in the Southern Hemisphere, the location of the TEJ is consistent with the suggestion that it is the equatorward outflow of convection that produces the TEJ. The paper notes that rainfall and river flow is largely influenced by groundwater base flow, and a return to sustained river flow requires replenishment of the aquifers, which is possible only with cumulative raining years. The paper confirms that there is correlation between the decrease in rainfall and low river flows.

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