Study of climate variability and change in the Republic of Djibouti: intense trends and events simulated by regional modeling

Started in september 2021

Funding: ‘campus France’ grant

Supervisors: Pierre Camberlin (université de Bourgogne), Benjamin Pohl (université de Bourgogne), Omar Assowe Dabar (CERD)

Abstract

East Africa is one of the regions that has suffered the hardest in the world from the climatic fluctuations of the last decades, due to its vulnerability which combines a low capacity for adaptation and an acute dependence on natural resources, in particular agriculture and water. Extreme weather events are common in the region and lead to floods and droughts associated with devastating socio-economic losses. The Republic of Djibouti in particular is characterized by an arid context coupled with a high variability of rainfall which generates flash floods causing serious damage to the population and to infrastructure. However, the fundamental mechanisms controlling the dynamics of the climate in Djibouti and in the region remain poorly understood. Understanding climate variability and expected future changes in climatic conditions, especially the characteristics of precipitation, temperature, wind, humidity and evapotranspiration is therefore crucial in planning and designing appropriate adaptation strategies.

The main objectives of this thesis are first of all to study the observed long-term trends for extreme events (rainfall and temperature) in Djibouti. This will be accomplished through a combination of analysis of surface climate observations, remote sensing products and atmospheric reanalysis (ERA5). High resolution climate simulations, including temperature, precipitation, winds, will be carried out as a second step. Climate variability and change over long time scales are often studied using global climate models, also called general circulation models (GCMs). GCMs coupled with a dynamic downscaling using the regional climate model (RCM) like WRF, implemented at the CRC of the University of Burgundy, can be used to simulate the current and future climate at high horizontal resolution (e.g. example, a 3 km grid scale) in Djibouti. These high-resolution models will allow us to identify the mechanisms responsible for extreme events (heavy rain or drought) and the evolution of these events in the future. On the other hand, phase 6 of the coupled inter-model comparison project (CMIP6) (Eyring et al., 2016) recently generated a new grid of simulations which represent different scenarios of greenhouse gas concentration trajectories (GES). We will use long simulations (2020-2100) and perform shorter simulations with high spatial resolution to document intense events and their occurrence on Djiboutian territory. The work will be based on a daily observation network of 40 rain gauges deployed in 2013 by the National Meteorological Agency of Djibouti across the country.

Reference

V. Eyring, S. Bony, G. A. Meehl, C. A. Senior, B. Stevens, R. J. Stouffer, K. E. Taylor. Overview of the Coupled Model Intercomparison Project Phase 6 (CMIP6) experimental design and organization. Geosci. Model Dev., 9, 1937–1958, 2016. https://doi.org/10.5194/gmd-9-1937-2016.

Keywords

Climate change and variability ; Republic of Djibouti ; intense trends and events ; regional climate modeling

Thesis advisory panel

Yves Tramblay, IRD Montpellier
Nathalie Philippon, CRC

extrait:

lien_externe:

titre:

Étude de la variabilité et du changement climatique dans la République de Djibouti : tendances et événements intenses simulés par la modélisation régionale

date_de_debut_these:

septembre 2021

nom:

Mohamed Waberi

date_de_debut_these_numerique:

202109

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kc_raw_content:

Study of climate variability and change in the Republic of Djibouti: intense trends and events simulated by regional modeling

Started in september 2021

Funding: 'campus France' grant

Supervisors: Pierre Camberlin (université de Bourgogne), Benjamin Pohl (université de Bourgogne), Omar Assowe Dabar (CERD)

 

Abstract

East Africa is one of the regions that has suffered the hardest in the world from the climatic fluctuations of the last decades, due to its vulnerability which combines a low capacity for adaptation and an acute dependence on natural resources, in particular agriculture and water. Extreme weather events are common in the region and lead to floods and droughts associated with devastating socio-economic losses. The Republic of Djibouti in particular is characterized by an arid context coupled with a high variability of rainfall which generates flash floods causing serious damage to the population and to infrastructure. However, the fundamental mechanisms controlling the dynamics of the climate in Djibouti and in the region remain poorly understood. Understanding climate variability and expected future changes in climatic conditions, especially the characteristics of precipitation, temperature, wind, humidity and evapotranspiration is therefore crucial in planning and designing appropriate adaptation strategies.

The main objectives of this thesis are first of all to study the observed long-term trends for extreme events (rainfall and temperature) in Djibouti. This will be accomplished through a combination of analysis of surface climate observations, remote sensing products and atmospheric reanalysis (ERA5). High resolution climate simulations, including temperature, precipitation, winds, will be carried out as a second step. Climate variability and change over long time scales are often studied using global climate models, also called general circulation models (GCMs). GCMs coupled with a dynamic downscaling using the regional climate model (RCM) like WRF, implemented at the CRC of the University of Burgundy, can be used to simulate the current and future climate at high horizontal resolution (e.g. example, a 3 km grid scale) in Djibouti. These high-resolution models will allow us to identify the mechanisms responsible for extreme events (heavy rain or drought) and the evolution of these events in the future. On the other hand, phase 6 of the coupled inter-model comparison project (CMIP6) (Eyring et al., 2016) recently generated a new grid of simulations which represent different scenarios of greenhouse gas concentration trajectories (GES). We will use long simulations (2020-2100) and perform shorter simulations with high spatial resolution to document intense events and their occurrence on Djiboutian territory. The work will be based on a daily observation network of 40 rain gauges deployed in 2013 by the National Meteorological Agency of Djibouti across the country.

 

Reference

V. Eyring, S. Bony, G. A. Meehl, C. A. Senior, B. Stevens, R. J. Stouffer, K. E. Taylor. Overview of the Coupled Model Intercomparison Project Phase 6 (CMIP6) experimental design and organization. Geosci. Model Dev., 9, 1937–1958, 2016. https://doi.org/10.5194/gmd-9-1937-2016.

 

Keywords

Climate change and variability ; Republic of Djibouti ; intense trends and events ; regional climate modeling

 

Thesis advisory panel

Yves Tramblay, IRD Montpellier
Nathalie Philippon, CRC