Hotspots, co-occurrence, and shifts of compound and cascading extreme climate events in Eurasian drylands

• Published in: Environment International
• Main Authors: Huiqian Yu, Nan Lu, Bojie Fu, Lu Zhang, Mengyu Wang, Hanqin Tian
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2022
• Subjects: Climate extremes; Compound extreme events; Cascading extreme events; Hotspots; ST-DBSCAN; Spatial shifts; Environmental sciences; GE1-350; Arctic; Arctic Ocean; Climate change
• Online Access: https://doi.org/10.1016/j.envint.2022.107509; https://doaj.org/article/ddb2cffc6caf4832b43e78bab9df0c3f

Eurasian drylands are the regions that are most vulnerable to climate change. Climate extremes have caused enormous or even devastating impacts on ecosystems and the social economy in this region, and the compound climate extremes (com_CEs, two or more extreme events occurring simultaneously) and cascading climate extremes (cas_CEs, two or more extreme events occurring successively) have exacerbated these problems. However, little is known about the occurrence patterns of com_CEs and cas_CEs in the Eurasian drylands. Based on the ERA5 reanalysis data range from 1979 to 2020, we improved the methodology for the extraction of co-occurrence events and identified high-frequency types, their hotspots, and occurrence rhythms (seasonally and annually) in Eurasian drylands. Our results showed that com_CEs and cas_CEs have high similarities in the types and spatial hotspots of extreme events; however, the former has a wider geographical and spatial distribution, and the latter has a longer duration. Specifically, co-occurring drought and heatwave events (DH) frequently appear in South Asia and western mid-latitude regions during summer, while in the winter, high latitude regions should be alert to the co-occurrence of drought and low-temperature events (DT). Central Asia and the Mongolian Plateau regions are prone to frequent drought and wind events (DW), and wind and high precipitation events (WP) in the spring and autumn. We have noticed that mid-latitude may suffer from extreme events that have never occurred before, such as com_DH being scattered sporadically in the first two decades and suddenly surging in West Asia and East Asia after the year 2000, and com_DT migrating from high-latitude areas such as the Arctic Ocean coast to mid-latitudes. Our results contribute to understanding hotspots of co-occurring CEs in Eurasian drylands, where more efforts will be needed in the future, especially in mid-latitudes which may suffer extreme climate events that have never occurred before.