Abstract
Linking sinuosity, a fairly recently developed metric, with high temperature extremes (HTEs) can be both useful and insightful to better understand the physical mechanisms behind HTEs. However, it is not clear whether there exists a relationship between the sinuosity changes and HTE changes in present and future climate conditions over southeastern China. In this paper, the anomalous characteristics of the atmospheric circulation are quantified by sinuosity. Three sinuosity metrics are used in this study: individual sinuosity (SIN), aggregate sinuosity (ASIN), and comprehensive sinuosity (CSIN). Furthermore, we examine the relationship between sinuosity changes and HTE changes in present and future climate conditions. ASIN is strongly correlated with surface air temperature (SAT). We find that the influence of individual sinuosity (SIN) at different latitudes on the SAT of southeastern China is different. The SIN of low (middle) latitude isohypses has significant positive (negative) correlations with the SAT of southeastern China. The SIN of high-latitude isohypses is rather limited and can therefore be ignored. The projected relationship between the sinuosity changes and HTE changes in the late 21st century suggests similar results. The change in SAT is related to the changes in climate variables over southeastern China in the future, and these changes increase with the increase in Z500 or V850 and the decrease in U500. Moreover, the frequencies of large (small) comprehensive sinuosity (CSIN) values at low (mid) latitudes will increase. At the end of the 21st century, Z500 isohypses at different latitudes will have an obvious poleward shift. Our results indicate that measuring the aggregate waviness of the midtropospheric flow (via sinuosity) can provide insight regarding HTEs, and the climate model output can be used to examine the future likelihood of increased HTE.
Highlights
The probability of high temperature extreme occurrences is ever increasing over many parts of the world
The high temperature extremes (HTEs) can more appear when aggregate sinuosity (ASIN) is at its peak
The surface air temperature (SAT) of southeastern China becomes higher with greater ASIN
Summary
The probability of high temperature extreme (hereafter HTE) occurrences is ever increasing over many parts of the world. Southeastern China is one of the most vulnerable regions, and it plays a decisive role from societal and economic points of view. It is of great scientific and practical significance to analyze and study the characteristics and formation mechanism of HTEs in southeastern China, whether to understand the climate characteristics in this area or to predict HTEs in the future. Overlying geopotential height anomaly at middle to upper levels and temperature advection by the meridional wind at lower levels are the two most important circulation factors affecting SAT [20,21,22]. Different from the north, the HTEs over the central and southern regions of China are related to geopotential height anomalies and the advection of cold and warm air in the lower level. It is important to analyze SAT and the variables closely related to SAT in order to comprehensively understand the internal physical mechanisms that play dominant roles [21]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
