Relative humidity and agricultural activities dominate wildfire ignitions in Yunnan, Southwest China: Patterns, thresholds, and implications

Climate drivers of global wildfire burned area

“…In the same line are the results of Li and Banerjee [63], who found that regions in California with high temperature and high VPD exhibit high risk of wildfire occurrence. Furthermore, Ying et al [15] tested a range of climate and socioeconomic wildfire ignition factors for China, indicating that the most important climate factor is low relative humidity, in line with our results for central Asia.…”

“…For example, large boreal forest fires of North America, have been correlated to weather patterns that associate with strong winds, and low precipitation conditions [14]. Ying et al [15], indicated that the most important climate related ignition factor for the Chinese province of Yunnan is relative humidity. For Europe, significant correlation has been detected between large wildfires and high temperature for Spain [16,17], as well as for Italy [18], but also for Greece, along with other variables [19] such as humidity and high pressure.…”

Impacts of the Western Pacific and Indian Ocean Warm Pools on Wildfires in Yunnan, Southwest China: Spatial Patterns With Interannual and Intraannual Variations

“…For areas with abundant vegetation and high productivity, the wildfire regime is drought‐driven and chiefly regulated by temporal variation of precipitation (Abatzoglou & Williams, 2016; Hanes et al., 2019; Wu et al., 2014). Specifically, in Yunnan with the tropical and subtropical climate, the teleconnections of wildfire activities with the intraannual dynamics of Indo‐Pacific warm pool should be mediated by the monsoons, through their regulation on rainfall dynamics, which is confirmed by the controlling role of air humidity on wildfire frequency in this region (Ying et al., 2021). Studies have also shown a negative correlation of summer rainfall in Southwest China with the simultaneous size and temperature of IO warm pool, and a positive correlation with that of the WP warm pool (Cao et al., 2014; Ueda et al., 2015).…”

“…Each record with the time and location of wildfire were used here, and 5,483 records in 18 years were collected. Undeniably, most ignition sources of wildfire were from human activities, but wildfire occurrence must dominantly be attributed to the air moisture and other climatic conditions in Yunnan (Cui et al., 2022; Ying et al., 2021). Obviously characterized by climatic conditions, with about 99% of the total fire number in winter and spring, there are indeed distinction on wildfire number between the locally practical fire alarming season (winter and spring, or December‐May) and nonfire alarming season (summer and autumn, or June‐November) across Yunnan (Figures 2a and 2b).…”

“…Yunnan Province located at southwestern China, adjacent to the Indo-China Peninsula and between the WP and IO (Figure 1). The wildfire regime in is region is similar to that in the Indo-China Peninsula, both jointly influenced by the WP and IO monsoons (Ying et al, 2021). This study would focus on the spatiotemporal patterns of wildfire number, and explore the effects of warm pools on wildfire activities in Yunnan.…”