Atomospheric Circulation Patterns Associated With Wildfires in the Monsoon Regions of China

Major atmospheric circulation patterns for wildfires have been identified in regions with boreal, Mediterranean, and semiarid climates. This study investigates such patterns in the monsoon regions of China, where the climate is controlled by multiple atmospheric systems and wildfires have large spatial variability. We identified three patterns. The first pattern was characterized by a high-pressure ridge in northeast China and contributed to wildfires by creating warmer and drier conditions. The second, meridional pattern contributed to wildfires in north, central, and south China by increasing dry air transport. The third, zonal pattern had a weaker westerly ridge and trough and contributed to wildfires in southwest China by decreasing the transport from westerly systems. We showed that a circulation index defined as the pressure difference between the positive and negative centers of fire-pressure correlations had higher monthly fire prediction skills for large fire occurrences than local weather. Plain Language Summary Atmospheric circulation as a driver of wildfire changes spatially. This study investigated the circulation patterns associated with wildfires and their regional dependence in the monsoon regions of China. We identified three patterns. The first pattern of positive pressure anomalies contributed to wildfires in northeast China with a cool temperate monsoon climate. The second pattern of strong southerly airflows contributed to wildfires in north, central, and south China with a subtropical East Asian monsoon climate. The third pattern of strong westerly airflows contributed to wildfires in southwest China with a subtropical South Asian monsoon climate. We showed that a circulation index formed based on the circulation patterns had higher prediction skills for large fire occurrences than local weather.