Uncertainty of rainfall products: impact on modelling household nutrition from rain-fed agriculture in Southern Africa

  • Good quality data on precipitation are a prerequisite for applications like short-term weather forecasts, medium-term humanitarian assistance, and long-term climate modelling. In Sub-Saharan Africa, however, the meteorological station networks are frequently insufficient, as in the Cuvelai-Basin in Namibia and Angola. This paper analyses six rainfall products (ARC2.0, CHIRPS2.0, CRU-TS3.23, GPCCv7, PERSIANN-CDR, and TAMSAT) with respect to their performance in a crop model (APSIM) to obtain nutritional scores of a household’s requirements for dietary energy and further macronutrients. All products were calibrated to an observed time series using Quantile Mapping. The crop model output was compared against official yield data. The results show that the products (i) reproduce well the Basin’s spatial patterns, and (ii) temporally agree to station records (r = 0.84). However, differences exist in absolute annual rainfall (range: 154 mm), rainfall intensities, dry spell duration, rainy day counts, and the rainy season onset. Though calibration aligns key characteristics, the remaining differences lead to varying crop model results. While the model well reproduces official yield data using the observed rainfall time series (r = 0.52), the products’ results are heterogeneous (e.g., CHIRPS: r = 0.18). Overall, 97% of a household’s dietary energy demand is met. The study emphasizes the importance of considering the differences among multiple rainfall products when ground measurements are scarce.

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Author:Robert LütkemeierORCiDGND, Lina Stein, Lukas DreesORCiDGND, Hannes Müller, Stefan LiehrORCiDGND
Parent Title (German):Water
Place of publication:Basel
Document Type:Article
Date of Publication (online):2018/04/18
Date of first Publication:2018/04/18
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2021/02/01
Tag:food security; model uncertainty; remote sensing; satellite rainfall estimates; subsistence agriculture
Issue:Article 499
Page Number:23
Institutes:Biowissenschaften / Biowissenschaften
Fachübergreifende Einrichtungen / Biodiversität und Klima Forschungszentrum (BiK-F)
Angeschlossene und kooperierende Institutionen / Institut für sozial-ökologische Forschung (ISOE)
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften
6 Technik, Medizin, angewandte Wissenschaften / 63 Landwirtschaft / 630 Landwirtschaft und verwandte Bereiche
Licence (German):License LogoCreative Commons - Namensnennung 4.0