Changes in temperature and heat waves over Africa using observational and reanalysis data sets. (3rd August 2021)

• Record Type: Journal Article
• Authors: Engdaw, Mastawesha Misganaw; Ballinger, Andrew P.; Hegerl, Gabriele C.; Steiner, Andrea K.
• Is Part Of: International journal of climatology. Volume 42:Number 2(2022)
• Page Start: 1165
• Page End: 1180
• Publication Date: 2021-08-03
• Subjects: Africa -- climate change -- heat waves -- observations -- reanalysis -- temperature extremes -- time of emergence; Climatology -- Periodicals; Climat -- Périodiques; Climatologie -- Périodiques; 551.605
• DOI: 10.1002/joc.7295
• Languages: English
• ISSNs: 0899-8418

Abstract

Abstract: 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. Abstract : Observations and reanalyses show significant warming over the African continent for 1980–2018, with varying strength in different regions. Heat wave occurrence increased at regional‐ and local‐scales and has emerged over natural variability. In 2010 and 2016, an extraordinary heat waves occurred over Northern and Eastern Africa, respectively. Overall, hot extremes increased in all regions of Africa and have emerged from natural variability in the past one or two decades. The findings contribute to fill the serious climate information gap over Africa.