A slow rainy season onset is a reliable harbinger of drought in most food insecure regions in Sub-Saharan Africa

Since 2015, Sub-Saharan Africa (SSA) has experienced an unprecedented rise in acute food insecurity (AFI), and current projections for the year 2020 indicate that more than 100 million Africans are estimated to receive emergency food assistance. Climate-driven drought is one of the main contributing factors to AFI, and timely and appropriate actions can be taken to mitigate impacts of AFI on lives and livelihoods through early warning systems. To support this goal, we use observations of peak Normalized Difference Vegetation Index (NDVI) as an indicator of seasonal drought conditions following a rainy season to show that delays in the onset of the rainy season (onset date) can be an effective early indicator of seasonal drought conditions. The core of this study is an evaluation of the relationship of the onset dates and peak NDVI, stratified by AFI risks, calculated using AFI reports by the United States Agency of International Development (USAID)-funded Famine Early Warning Systems Network (FEWS NET). Several parts of SSA, mostly located in East Africa (EA), reported the “Crisis” phase of AFI—requiring emergency food assistance—at least one-third of the time between April 2011 to present. The results show that the onset date can effectively explain much of the interannual variability in peak NDVI in the regions with the highest AFI risk level, particularly in EA where the median of correlation (across all the Administrative Unit 2) varies between -0.42 to -0.68. In general, an onset date delay of at least 1 dekad (10 days) increases the likelihood of seasonal drought conditions. In the regions with highest risks of AFI, an onset delay of just 1 dekad doubles the chance of the standardized anomaly of peak NDVI being below -1, making a -1 anomaly the most probable outcome. In those regions, a 2-dekads delay in the onset date is associated with a very high probability (50%) of seasonal drought conditions (-1 standardized anomaly of NDVI). Finally, a multivariate regression analysis between standardized anomaly and onset date anomaly further substantiates the negative impacts of delay in onset date on NDVI anomaly. This relationship is statistically significant over the SSA as a whole, particularly in the EA region. These results imply that the onset date can be used as an additional critical tool to provide alerts of seasonal drought development in the most food-insecure regions of SSA. Early warning systems using onset date as a tool can help trigger effective mid-season responses to save human lives, livestock, and livelihoods, and, therefore, mitigate the adverse impacts of drought hazards.

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How can policy makers in sub-Saharan Africa make early warning systems more effective? The case of Uganda

International Journal of Disaster Risk Reduction ◽

10.1016/j.ijdrr.2017.11.017 ◽

2018 ◽

Vol 27 ◽

pp. 530-540 ◽

Cited By ~ 10

Author(s):

Darren Lumbroso

Keyword(s):

Early Warning ◽

Early Warning Systems ◽

Sub Saharan Africa ◽

Warning Systems ◽

Policy Makers ◽

Sub Saharan

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The influence of antecedent conditions on flood risk in sub-Saharan Africa

10.5194/nhess-2017-58 ◽

2017 ◽

Author(s):

Konstantinos Bischiniotis ◽

Bart van den Hurk ◽

Brenden Jongman ◽

Erin Coughlan de Perez ◽

Ted Veldkamp ◽

...

Keyword(s):

Early Warning Systems ◽

Sub Saharan Africa ◽

Lead Times ◽

Warning Systems ◽

Antecedent Conditions ◽

Seasonal Scale ◽

Additional Input ◽

Sub Saharan ◽

Flood Generation

Abstract. Most flood early warning systems have predominantly focused on forecasting floods with lead times of hours or days. However, physical processes during longer – seasonal – time scales can also contribute to flood generation. In this study, the hydro-meteorological pre-conditions of 501 historical damaging flood events over the period 1980 to 2010 in sub-Saharan Africa are analyzed. These are separated into a) a short-term weather scale period (0–7 days) and b) a long-term seasonal-scale period (up to 6 months) before the flood event. Total 7-day precipitation is used to evaluate weather-scale conditions, while seasonal-scale conditions are reflected in the Standardized Precipitation Evapotranspiration Index (SPEI). Although the latter has been used for drought detection, because of its characteristics can also become a wetness monitoring tool. Results indicate that, although heavy 7-day lead precipitation is connected with the majority of the reported floods (72 %), more than 50 % of all floods exhibited higher than average antecedent conditions during the 6 preceding months. In case of extremely wet weather and seasonal scale conditions (SPEI > 2) the probability of flood is close to 50 %. The combined analysis of the two periods revealed that seasonal-scale information should not be neglected, and seasonal SPEI information could be a useful – additional – input to the weather-scale flood forecasts to improve flood preparedness.

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The influence of antecedent conditions on flood risk in sub-Saharan Africa

Natural Hazards and Earth System Science ◽

10.5194/nhess-18-271-2018 ◽

2018 ◽

Vol 18 (1) ◽

pp. 271-285 ◽

Cited By ~ 8

Author(s):

Konstantinos Bischiniotis ◽

Bart van den Hurk ◽

Brenden Jongman ◽

Erin Coughlan de Perez ◽

Ted Veldkamp ◽

...

Keyword(s):

Flood Risk ◽

Early Warning Systems ◽

Sub Saharan Africa ◽

Lead Times ◽

Warning Systems ◽

Pragmatic Approach ◽

Physical Processes ◽

Antecedent Conditions ◽

Sub Saharan ◽

Flood Generation

Abstract. Most flood early warning systems have predominantly focused on forecasting floods with lead times of hours or days. However, physical processes during longer timescales can also contribute to flood generation. In this study, we follow a pragmatic approach to analyse the hydro-meteorological pre-conditions of 501 historical damaging floods from 1980 to 2010 in sub-Saharan Africa. These are separated into (a) weather timescale (0–6 days) and (b) seasonal timescale conditions (up to 6 months) before the event. The 7-day precipitation preceding a flood event (PRE7) and the standardized precipitation evapotranspiration index (SPEI) are analysed for the two timescale domains, respectively. Results indicate that high PRE7 does not always generate floods by itself. Seasonal SPEIs, which are not directly correlated with PRE7, exhibit positive (wet) values prior to most flood events across different averaging times, indicating a relationship with flooding. This paper provides evidence that bringing together weather and seasonal conditions can lead to improved flood risk preparedness.

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Systematic User Feedback to Co-develop a Flood Early Warning System in West Africa

10.5194/egusphere-egu21-3136 ◽

2021 ◽

Author(s):

Martijn Kuller ◽

Jafet Andersson ◽

Judit Lienert

Keyword(s):

West Africa ◽

Early Warning ◽

Rainy Season ◽

Emergency Services ◽

Early Warning Systems ◽

End Users ◽

General Assembly ◽

Warning Systems ◽

System Components ◽

Hydrological Services

IntroductionThe Horizon 2020 project FANFAR (www.fanfar.eu) aims to develop a Flood Early Warning Systems (FEWS) for West Africa. Prospective end-users of the FANFAR system include the hydrological services and emergency services of 17 countries in West Africa. Close involvement of end-users during the development phase can enhance effectiveness and usefulness of early warning systems (Reid, 2006). Therefore, FANFAR took a co-development approach between the consortium of developers and the end-users (Andersson, Ali, et al., 2020). Important vehicle for co-development are three workshops, organised over three years by the development consortium. Workshops were attended by one representative from hydrological services and one from emergency services from each country. The objectives of co-development included: tailoring to user- and context specific preferences and requirements, acquiring technical feedback on system components, enhancing user skills and capacity, building trust and ownership, enabling performance testing and enhancing system uptake.ApproachSeveral strategies and interventions have been deployed to meet the objectives. Firstly, a Multi-Criteria Decision Analysis was conducted to establish the end-users&#8217; primary objectives and system configurations to best meet these (Lienert, Andersson, & Silva Pinto, 2020). Furthermore, including the execution of regular surveys to explore user experiences with the system and receive technical feedback. Two different pen-and-paper surveys were taken during the both the second and third workshop sessions: (1) a survey exploring long-term and detailed information on usage, performance, preferences, obstacles and experience of using FANFAR and (2) a survey eliciting detailed technical feedback on separate system components. A third, shorter survey was conducted online on a monthly basis during the rainy season (May-October 2020) focussing on day-to-day operational usage and performance. Here, we summarise some main insights from these three types of surveys.OutcomesThe data on user experience with the FANFAR system gathered during these interventions enabled the development team to improve the forecast system. For example, accuracy was identified as critical issue to improve. In response, the development team initiated several activities aimed at improving accuracy, including model calibration, catchment re-delineation, assimilation of local streamflow observations and EO data, and utilising alternative meteorological data (Andersson, Santos, et al., 2020).There was an important discrepancy between the reported overwhelming intention to use FANFAR (82-93%) and the actual usage (28-46%). One reason could be related to the reported barrier posed by the initial state of the system, and the lack of accuracy mentioned above. Furthermore, priorities and resources might partly explain these numbers. However, these finding could be skewed by the changing composition of respondents between surveys, compromising their representativeness. Indeed, the user statistics of the online platform show a rise in visits. Finally, users seem to prioritise a functional system delivering daily predictions over a complex system with broad functionality.Overall, our co-development has been a positive one. Participation has been strong and continuous, with an increasing number of organisations and their representatives partaking in workshops. In addition, participation outside the workshops (during the rainy season) was encouraging, particularly in the light of its voluntary nature.References Andersson, J., Ali, A., Arheimer, B., Crochemore, L., Gbobaniyi, B., Gustafsson, D., . . . Machefer, M. (2020). Flood forecasting and alerts in West Africa-experiences from co-developing a pre-operational system at regional scale. Paper presented at the EGU General Assembly Conference Abstracts. Andersson, J., Santos, L., Isberg, K., Gustafsson, D., Musuuza, J., Minoungou, B., & Crochemore, L. (2020). Deliverable: D3.2 Report documenting and explaining the hydrological models. Retrieved from available at: https://fanfar.eu/resources/: Lienert, J., Andersson, J., & Silva Pinto, F. (2020). Co-designing a flood forecasting and alert system in West Africa with decision-making methods: the transdisciplinary project FANFAR. Paper presented at the EGU General Assembly Conference Abstracts. Reid, B. (2006). Global early warning systems for natural hazards: systematic and people-centred. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 364(1845), 2167-2182. doi:doi:10.1098/rsta.2006.1819

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The CARE Telematics Network for the Surveillance of Influenza in Europe

Methods of Information in Medicine ◽

10.1055/s-0038-1634617 ◽

1995 ◽

Vol 34 (05) ◽

pp. 518-522 ◽

Cited By ~ 13

Author(s):

M. Bensadon ◽

A. Strauss ◽

R. Snacken

Keyword(s):

Public Health ◽

Early Warning ◽

Early Warning Systems ◽

Warning Systems ◽

Surveillance Networks ◽

Spanish Flu ◽

The 1950S ◽

National Networks ◽

First Time

Abstract:Since the 1950s, national networks for the surveillance of influenza have been progressively implemented in several countries. New epidemiological arguments have triggered changes in order to increase the sensitivity of existent early warning systems and to strengthen the communications between European networks. The WHO project CARE Telematics, which collects clinical and virological data of nine national networks and sends useful information to public health administrations, is presented. From the results of the 1993-94 season, the benefits of the system are discussed. Though other telematics networks in this field already exist, it is the first time that virological data, absolutely essential for characterizing the type of an outbreak, are timely available by other countries. This argument will be decisive in case of occurrence of a new strain of virus (shift), such as the Spanish flu in 1918. Priorities are now to include other existing European surveillance networks.

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