Preprints
https://doi.org/10.5194/gmd-2021-54
https://doi.org/10.5194/gmd-2021-54

Submitted as: model evaluation paper 07 May 2021

Submitted as: model evaluation paper | 07 May 2021

Review status: this preprint is currently under review for the journal GMD.

Precipitation over southern Africa: Is there consensus among GCMs, RCMs and observational data?

Maria Chara Karypidou1, Eleni Katragkou1, and Stefan Pieter Sobolowski2 Maria Chara Karypidou et al.
  • 1Department of Meteorology and Climatology, School of Geology, Faculty of Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
  • 2NORCE Norwegian Research Centre, Bjerknes Centre for Climate Research, Bergen, Norway

Abstract. The region of southern Africa (SAF) is highly vulnerable to the impacts of climate change and is projected to experience severe precipitation shortages in the coming decades. Ensuring that our modelling tools are fit for the purpose of assessing these changes is critical. In this work we compare a range of satellite products along with gauge-based datasets. Additionally, we investigate the behaviour of regional climate simulations from the Coordinated Regional Climate Downscaling Experiment (CORDEX) – Africa domain, along with simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) and Phase 6 (CMIP6). We identify considerable variability in the standard deviation of precipitation between satellite products that merge with rain gauges and satellite products that do not, during the rainy season (Oct–Mar), indicating high observational uncertainty for specific regions over SAF. Good agreement both in spatial pattern and the strength of the calculated trends is found between satellite and gauge-based products, however. Both CORDEX-Africa and CMIP5 ensembles underestimate the observed trends during the analysis period. The CMIP6 ensemble displayed persistent drying trends, in direct contrast to the observations. The regional ensemble exhibited improved performance compared to its forcing (CMIP5), when the annual cycle and the extreme precipitation indices were examined, confirming the added value of the higher resolution regional climate simulations. The CMIP6 ensemble displayed a similar behaviour to CMIP5, however reducing slightly the ensemble spread. However, we show that reproduction of some key SAF phenomena, like the Angolan Low (which exerts a strong influence on regional precipitation), still poses a challenge for the global and regional models. This is likely a result of the complex climatic process that take place. Improvements in observational networks (both in-situ and satellite), as well as continued advancements in high-resolution modelling will be critical, in order to develop a robust assessment of climate change for southern Africa.

Maria Chara Karypidou et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on gmd-2021-54', Anonymous Referee #1, 10 Jun 2021
    • AC1: 'Reply on RC1', Maria Chara Karypidou, 15 Nov 2021
  • RC2: 'Comment on gmd-2021-54', Anonymous Referee #2, 18 Jun 2021
    • AC2: 'Reply on RC2', Maria Chara Karypidou, 16 Nov 2021

Maria Chara Karypidou et al.

Maria Chara Karypidou et al.

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Short summary
The region of southern Africa (SAF) is highly vulnerable to the impacts of climate change and is projected to experience severe precipitation shortages in the coming decades. Reliable climatic information is therefore necessary for the optimal adaptation of local communities. In this work we show that regional climate models are reliable tools for the simulation of precipitation over southern Africa. However, there is still a great need for the expansion and maintenance of observational data.