Spatial and Temporal Variations of Compound Droughts and Hot Extremes in China

Abstract

Droughts and hot extremes may lead to tremendous impacts on the ecosystem and different sectors of the society. A variety of studies have been conducted on the variability of the individual drought or hot extreme in China. However, the evaluation of compound droughts and hot extremes, which may induce even larger impacts than the individual drought or hot extreme, is still lacking. The aim of this study is to investigate changes in the frequency and spatial extent of compound droughts and hot extremes during summer in China using monthly precipitation and daily temperature data from 1953 to 2012. Results show that a high frequency of compound droughts and hot extremes mostly occur in the regions stretching from northeast to southwest of China. There is an overall increase in the frequency of co-occurrence of droughts and hot extremes across most parts of China with distinct regional patterns. In addition, an increasing trend in the areas covered by compound extremes has been observed, especially after the 1990s. At regional scales, the increase of the frequency and spatial extent of compound extremes has been shown to be most profound in North China (NC), South China (SC), and Southwest China (SWC), while the decrease of compound extremes was found in Central China (CC). These results show the variability of compound droughts and hot extremes and could provide useful insights into the mitigation efforts of extreme events in China.

Compound Droughts and Heat Waves in China

“…The rising trend of heat wave frequency is more significant than that of droughts. Wu et al [35] investigated changes in the frequency of compound droughts and heat waves in China and concluded that an increase in the frequency and spatial extent was mainly shown in NC, SC, and SWC, while our results show that the most significant increase is NEC, NC, and SWC.…”

“…China is located in the southeastern Eurasian continent and belongs to the East Asian monsoon climate, covering approximately 9.6 million square kilometers and has the world's largest population. Due to complex natural and social conditions, China is divided into seven regions in Figure 1 according to natural and socioeconomic situations at the provincial scale like other studies [35]: Northeast China (NEC), North China (NC), Northwest China (NWC), Southwest China (SWC), Central China (CC), South China (SC), and East China (EC).…”

Increase in Compound Drought and Heatwaves in a Warming World

“…These CDHW events often impact socio‐ecological systems (Mukherjee et al., 2020), which includes wildfires (Sutanto et al., 2020; Witte, 2011), massive heat‐related deaths (D'Ippoliti et al., 2010; Mitchell et al., 2016), and loss of crop yield (Lu et al., 2018; Zampieri et al., 2017). Many regions around the world experienced CDHW events during the summer months of 2003, 2010, 2015, and 2018 in Europe and western Russia (Fink et al., 2004; Ionita et al., 2017; Liu et al., 2020; Witte, 2011); 2012–2014 in the USA (Diaz & Wahl, 2015; Griffin & Anchukaitis, 2014; Williams et al., 2015); 2013 in Australia (Cowan et al., 2014; Lewis & Karoly, 2013); 2006, 2009–2010, and 2014 in Southwestern and Northern China (Barriopedro et al., 2012; H. Wang & He, 2015; X. Wu et al., 2019; Ye et al., 2019).…”

Projected increase in compound dry and hot events over global land areas

“…Previous studies have shown a significant increase in the frequency and spatial extent of compound dry and hot events in many regions or countries, such as America (Mazdiyasni and AghaKouchak, 2015), India (Sharma and Mujumdar, 2017), and China (Li et al ., 2019; Wu et al ., 2019). At the global scale, several recent investigations based on historical records have demonstrated the variation in compound dry and hot events mainly in terms of their frequency or severity, and an increase was detected in most parts of the world (Hao et al ., 2013; Zscheischler and Seneviratne, 2017; Sarhadi et al ., 2018).…”