TY - JOUR
T1 - Changes in temperature and heat waves over Africa using observational and reanalysis data sets
AU - Engdaw, Mastawesha Misganaw
AU - Ballinger, Andrew P.
AU - Hegerl, Gabriele C.
AU - Steiner, Andrea K.
N1 - Funding Information:
This study was funded by the Austrian Science Fund (FWF) under Research Grant W1256 (Doctoral Programme Climate Change: Uncertainties, Thresholds and Coping Strategies, http://dk-climate-change.uni-graz.at). Mastawesha Misganaw Engdaw's bench fee at University of Edinburgh was paid by the Sigrist foundation for the 6 months research visit, and GCH was also supported by NERC grant Emergence (NE/S004661/1). Mastawesha Misganaw Engdaw thanks GCH's research team at the School of Geosciences, University of Edinburgh, UK, for the fruitful discussions and support provided during the research visit. The authors acknowledge the Centre for Environmental Data Analysis (CEDA), the Berkeley Earth Surface Temperature (BEST), the European Centre for Medium-Range Weather Forecasts (ECMWF), the National Oceanic Atmospheric Administration (NOAA) and the Japanese Meteorological Agency (JMA) for making CRU, BEST, ERA5, MERRA2 and JRA-55 data sets available online, respectively.
Funding Information:
This study was funded by the Austrian Science Fund (FWF) under Research Grant W1256 (Doctoral Programme Climate Change: Uncertainties, Thresholds and Coping Strategies, http://dk-climate-change.uni-graz.at ). Mastawesha Misganaw Engdaw's bench fee at University of Edinburgh was paid by the Sigrist foundation for the 6 months research visit, and GCH was also supported by NERC grant Emergence (NE/S004661/1). Mastawesha Misganaw Engdaw thanks GCH's research team at the School of Geosciences, University of Edinburgh, UK, for the fruitful discussions and support provided during the research visit. The authors acknowledge the Centre for Environmental Data Analysis (CEDA), the Berkeley Earth Surface Temperature (BEST), the European Centre for Medium‐Range Weather Forecasts (ECMWF), the National Oceanic Atmospheric Administration (NOAA) and the Japanese Meteorological Agency (JMA) for making CRU, BEST, ERA5, MERRA2 and JRA‐55 data sets available online, respectively.
Publisher Copyright:
© 2021 The Authors. International Journal of Climatology published by John Wiley & Sons Ltd on behalf of Royal Meteorological Society.
PY - 2022/2/7
Y1 - 2022/2/7
N2 - Providing comprehensive regional- and local-scale information on changes observed in the climate system plays a vital role in planning effective and efficient climate change adaptation options, specifically over resource-limited regions. Here, we assess changes in temperature and heat waves over different regions of the African continent, with a focus on spatiotemporal trends and the time of emergence of change in hot extremes from natural variability. We analyse absolute and relative threshold indices. Data sets include temperatures from observations (CRUTS4.03 and BEST) and from three representative state-of-the-art reanalyses (ERA5, MERRA2 and JRA-55) for the common period 1980–2018. Statistically significant warming is observed over all regions of Africa in temperature time series from CRU observations and reanalysis data, although the trend strength varies between data sets. Also, extreme temperatures and heat wave indices from BEST observations and all reanalysis data sets reveal increasing trends over all regions of the African continent. However, there are differences in both trend strength and time evolution of heat wave indices between different reanalysis data sets. Most data sets agree in identifying 2010 as a peak heat year over Northern and Western Africa while Eastern and Southern Africa experienced the highest heat wave occurrence in 2016. Our results clearly reveal that heat wave occurrences have emerged from natural climate variability in Africa. The earliest time of emergence takes place in the Northern Africa region in the early 2000s while in the other African regions emergence over natural variability is found mainly after 2010. This also depends on the respective index metrics, where indices based on more consecutive days show later emergence of heat wave trends. Overall, significant warming and an increase in heat wave occurrence is found in all regions of Africa and has emerged from natural variability in the past one or two decades.
AB - Providing comprehensive regional- and local-scale information on changes observed in the climate system plays a vital role in planning effective and efficient climate change adaptation options, specifically over resource-limited regions. Here, we assess changes in temperature and heat waves over different regions of the African continent, with a focus on spatiotemporal trends and the time of emergence of change in hot extremes from natural variability. We analyse absolute and relative threshold indices. Data sets include temperatures from observations (CRUTS4.03 and BEST) and from three representative state-of-the-art reanalyses (ERA5, MERRA2 and JRA-55) for the common period 1980–2018. Statistically significant warming is observed over all regions of Africa in temperature time series from CRU observations and reanalysis data, although the trend strength varies between data sets. Also, extreme temperatures and heat wave indices from BEST observations and all reanalysis data sets reveal increasing trends over all regions of the African continent. However, there are differences in both trend strength and time evolution of heat wave indices between different reanalysis data sets. Most data sets agree in identifying 2010 as a peak heat year over Northern and Western Africa while Eastern and Southern Africa experienced the highest heat wave occurrence in 2016. Our results clearly reveal that heat wave occurrences have emerged from natural climate variability in Africa. The earliest time of emergence takes place in the Northern Africa region in the early 2000s while in the other African regions emergence over natural variability is found mainly after 2010. This also depends on the respective index metrics, where indices based on more consecutive days show later emergence of heat wave trends. Overall, significant warming and an increase in heat wave occurrence is found in all regions of Africa and has emerged from natural variability in the past one or two decades.
U2 - 10.1002/joc.7295
DO - 10.1002/joc.7295
M3 - Article
SN - 0899-8418
VL - 42
SP - 1165
EP - 1180
JO - International Journal of Climatology
JF - International Journal of Climatology
IS - 2
ER -