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Chinese Academy of Agricultural Sciences (2020)

Temporal and Spatial Changes of Drought in Africa and Its Impact on Agriculture from 2003 to 2017

Nusseiba NourEldeen Abdalla Esmaeel

Titre : Temporal and Spatial Changes of Drought in Africa and Its Impact on Agriculture from 2003 to 2017

Auteur : Nusseiba NourEldeen Abdalla Esmaeel;

Grade : Doctoral Dissertation 2020

Université : Chinese Academy of Agricultural Sciences

Résumé partiel
Over the past century,severe weather events have occurred over many parts of the African continent and resulted in severe drought-related hazards.Climate change,drought and land degradation are the leading factors threatening sustainable food and livestock production on the continent.This,in turn,will severely affect the wellbeing of the people,especially the rural farmers whose main livelihood depends on agriculture activities in rain-fed regions.Africa climate range from Sahara Desert in north part to tropical in south part with centred by savanna and forest rain zone,and endures land degradation and frequent droughts due to water shortages and high summer temperatures.The region has been affected by climate change and environmental degradation,which led to affect the crop production in continent.We found that the Sahelian countries of the Africa has been the most affected over the past decades and therefore our study focused on the Sahelian countries to understand the effect of drought on crop production as follows:First,we investigated the temporal and spatial variations of land surface temperature(LST)in Africa to determine the effects of temperature on agricultural production.Although thermal infrared remote sensing technology can quickly obtain surface temperature information,it is greatly affected by clouds and rainfall.To obtain a complete and continuous dataset on the spatiotemporal variations in LST in Africa,a reconstruction model based on the Moderate Resolution Imaging Spectroradiometer(MODIS)LST time series and ground station data was built to refactor the LST dataset(2003-2017).The spatiotemporal analysis of the LST indicates that the change in the annual average LST from 2003-2017 was weak and the warming trend in Africa was remarkably uneven.Geographically,"the warming is more pronounced in the north and the west than in the south and the east".The most significant warming occurred near the equatorial region in South Africa(slope > 0.05,R > 0.61,P <0.05)and the central(slope = 0.08,R = 0.89,P < 0.05)regions.Seasonally,significant warming was more pronounced in winter,mostly in the west,especially in Mauritania(slope> 0.09,R> 0.9,P <0.5*).Furthermore,the study gave a concise report on the response of different surface types to surface temperature was inconsistent at different times,which provides important information for understanding the effects of temperature changes on crop yields,which is critical for the planning of agricultural farming systems in Africa.Second,the study presents an overview of issues related to soil moister content which is a key step in studying the impacts of drought on food production in Africa.To obtain long-term soil moisture data sets in Africa,data products from three different sensors(Advanced Microwave Scanning Radiometer-EOS(AMSR-E),Soil Moisture and Ocean Salinity(SMOS),Advanced Microwave Scanning Radiometer 2(AMSR2))over Africa were used.To improve the resolution of the SM products,the spatial weight downscaling model(SWDM)was used to downscale the passive microwave SM data from 25 km to 1 km resolution.

Mots clés : Africa; land surface temperature; Soil moisture; drought vulnerability; downscaling;

Présentation (CNKI)

Page publiée le 3 juin 2021