Lamei Shi

Background: Regional climate controls on wildfires in China remain complex due to high spatial heterogeneity and strict suppression policies. Aims: This study aims to objectively identify coherent high-activity wildfire regions in China and clarify the climatic pathways regulating wildfire activity during the fire season. Methods: We applied an optimized clustering approach to MCD64A1 burned area data (2001–2024) to delineate fire regimes, and used Pearson and partial correlations to analyze regional climate-fire relationships. Key results: Two representative high-activity wildfire regions were identified: the Northeast fire regime area (NFR) and the Southwest fire regime area (SFR). Burned area peaks in both regions during February–April, when soil moisture (SM) deficit acts as a proximal control. However, the climatic drivers regulating SM differ between regions. In the NFR, SM is associated with both snow cover and temperature, both governed by February–March Arctic Oscillation (AO) conditions. SM in the SFR is negatively related to temperature, which is positively associated with February–March El Niño conditions. Conclusions: Winter-spring wildfires in the NFR are governed by a cryosphere–temperature pathway while in the SFR are dominated by a thermally driven pathway. Implications: These distinct climate-fire linkages emphasize the importance of region-specific wildfire research under strict fire suppression policies.

Wildfires can significantly enhance surface sensible heat and modify the state of the near-surface atmosphere, becoming key factors in triggering turbulence and restructuring the boundary layer. This study uses high-resolution simulations with WRF-Fire, combined with hourly observational data from six meteorological stations (five national and one emergency stations) during the Jinyun Mountain wildfire in Chongqing, China, to systematically evaluate the performance of five planetary boundary layer (PBL) schemes (MYJ, MYNN2, MYNN3, BouLac, UW) in simulating temperature, wind speed, and turbulence intensity. Results show that all schemes can reproduce the diurnal trends of temperature and wind speed but exhibit significant differences in amplitude response and simulation errors. The MYNN3 scheme captures the spatiotemporal variations of turbulence intensity and wind speed at different heights more accurately, thereby better representing the 2 m temperature and 10 m wind speed response and reduces the model's cold bias in high-temperature simulations. The BouLac and MYNN2 schemes also show some response to thermal disturbances at certain sites but perform poorly under strong perturbations and exhibit large fluctuations. The MYJ and UW schemes show overall weaker turbulence and fail to capture local circulation variations effectively. Turbulent energy budget analysis of MYNN3 indicates a buoyancy-dominated turbulence generation mechanism, with vertical transport promoting upper-level disturbances. This reveals MYNN3's greater sensitivity to wildfire thermal perturbations and more complete feedback processes, providing a scientific basis for selecting PBL schemes in mountainous wildfire simulations.

Wildfires can significantly enhance surface sensible heat and modify the state of the near-surface atmosphere, becoming key factors in triggering turbulence and restructuring the boundary layer. This study uses high-resolution simulations with WRF-Fire, combined with hourly observational data from six meteorological stations (five national and one emergency stations) during the Jinyun Mountain wildfire in Chongqing, China, to systematically evaluate the performance of five planetary boundary layer (PBL) schemes (MYJ, MYNN2, MYNN3, BouLac, UW) in simulating temperature, wind speed, and turbulence intensity. Results show that all schemes can reproduce the diurnal trends of temperature and wind speed but exhibit significant differences in amplitude response and simulation errors. The MYNN3 scheme captures the spatiotemporal variations of turbulence intensity and wind speed at different heights more accurately, thereby better representing the 2-meter temperature and 10-meter wind speed response and reduces the model’s cold bias in high-temperature simulations. The BouLac and MYNN2 schemes also show some response to thermal disturbances at certain sites but perform poorly under strong perturbations and exhibit large fluctuations. The MYJ and UW schemes show overall weaker turbulence and fail to capture local circulation variations effectively. Turbulent energy budget analysis of MYNN3 indicates a buoyancy-dominated turbulence generation mechanism, with vertical transport promoting upper-level disturbances. This reveals MYNN3’s greater sensitivity to wildfire thermal perturbations and more complete feedback processes, providing a scientific basis for selecting PBL schemes in mountainous wildfire simulations.

Wildfires can significantly enhance surface sensible heat and modify the state of the near-surface atmosphere, becoming key factors in triggering turbulence and restructuring the boundary layer. This study uses high-resolution simulations with WRF-Fire, combined with hourly observational data from six meteorological stations (five national and one emergency stations) during the Jinyun Mountain wildfire in Chongqing, China, to systematically evaluate the performance of five planetary boundary layer (PBL) schemes (MYJ, MYNN2, MYNN3, BouLac, UW) in simulating temperature, wind speed, and turbulence intensity. Results show that all schemes can reproduce the diurnal trends of temperature and wind speed but exhibit significant differences in amplitude response and simulation errors. The MYNN3 scheme captures the spatiotemporal variations of turbulence intensity and wind speed at different heights more accurately, thereby better representing the 2-meter temperature and 10-meter wind speed response and reduces the model’s cold bias in high-temperature simulations. The BouLac and MYNN2 schemes also show some response to thermal disturbances at certain sites but perform poorly under strong perturbations and exhibit large fluctuations. The MYJ and UW schemes show overall weaker turbulence and fail to capture local circulation variations effectively. Turbulent energy budget analysis of MYNN3 indicates a buoyancy-dominated turbulence generation mechanism, with vertical transport promoting upper-level disturbances. This reveals MYNN3’s greater sensitivity to wildfire thermal perturbations and more complete feedback processes, providing a scientific basis for selecting PBL schemes in mountainous wildfire simulations.

Wildfires can significantly enhance surface sensible heat and modify the state of the near-surface atmosphere, becoming key factors in triggering turbulence and restructuring the boundary layer. This study uses high-resolution simulations with WRF-Fire, combined with hourly observational data from six meteorological stations (five national and one emergency stations) during the Jinyun Mountain wildfire in Chongqing, China, to systematically evaluate the performance of five planetary boundary layer (PBL) schemes (MYJ, MYNN2, MYNN3, BouLac, UW) in simulating temperature, wind speed, and turbulence intensity. Results show that all schemes can reproduce the diurnal trends of temperature and wind speed but exhibit significant differences in amplitude response and simulation errors. The MYNN3 scheme captures the spatiotemporal variations of turbulence intensity and wind speed at different heights more accurately, thereby better representing the 2-meter temperature and 10-meter wind speed response and reduces the model’s cold bias in high-temperature simulations. The BouLac and MYNN2 schemes also show some response to thermal disturbances at certain sites but perform poorly under strong perturbations and exhibit large fluctuations. The MYJ and UW schemes show overall weaker turbulence and fail to capture local circulation variations effectively. Turbulent energy budget analysis of MYNN3 indicates a buoyancy-dominated turbulence generation mechanism, with vertical transport promoting upper-level disturbances. This reveals MYNN3’s greater sensitivity to wildfire thermal perturbations and more complete feedback processes, providing a scientific basis for selecting PBL schemes in mountainous wildfire simulations.

Wildfires can significantly enhance surface sensible heat and modify the state of the near-surface atmosphere, becoming key factors in triggering turbulence and restructuring the boundary layer. This study uses high-resolution simulations with WRF-Fire, combined with hourly observational data from six meteorological stations (five national and one emergency stations) during the Jinyun Mountain wildfire in Chongqing, China, to systematically evaluate the performance of five planetary boundary layer (PBL) schemes (MYJ, MYNN2, MYNN3, BouLac, UW) in simulating temperature, wind speed, and turbulence intensity. Results show that all schemes can reproduce the diurnal trends of temperature and wind speed but exhibit significant differences in amplitude response and simulation errors. The MYNN3 scheme captures the spatiotemporal variations of turbulence intensity and wind speed at different heights more accurately, thereby better representing the 2-meter temperature and 10-meter wind speed response and reduces the model’s cold bias in high-temperature simulations. The BouLac and MYNN2 schemes also show some response to thermal disturbances at certain sites but perform poorly under strong perturbations and exhibit large fluctuations. The MYJ and UW schemes show overall weaker turbulence and fail to capture local circulation variations effectively. Turbulent energy budget analysis of MYNN3 indicates a buoyancy-dominated turbulence generation mechanism, with vertical transport promoting upper-level disturbances. This reveals MYNN3’s greater sensitivity to wildfire thermal perturbations and more complete feedback processes, providing a scientific basis for selecting PBL schemes in mountainous wildfire simulations.

Wildfires can significantly enhance surface sensible heat and modify the state of the near-surface atmosphere, becoming key factors in triggering turbulence and restructuring the boundary layer. This study uses high-resolution simulations with WRF-Fire, combined with hourly observational data from six meteorological stations (five national and one emergency stations) during the Jinyun Mountain wildfire in Chongqing, China, to systematically evaluate the performance of five planetary boundary layer (PBL) schemes (MYJ, MYNN2, MYNN3, BouLac, UW) in simulating temperature, wind speed, and turbulence intensity. Results show that all schemes can reproduce the diurnal trends of temperature and wind speed but exhibit significant differences in amplitude response and simulation errors. The MYNN3 scheme captures the spatiotemporal variations of turbulence intensity and wind speed at different heights more accurately, thereby better representing the 2-meter temperature and 10-meter wind speed response and reduces the model’s cold bias in high-temperature simulations. The BouLac and MYNN2 schemes also show some response to thermal disturbances at certain sites but perform poorly under strong perturbations and exhibit large fluctuations. The MYJ and UW schemes show overall weaker turbulence and fail to capture local circulation variations effectively. Turbulent energy budget analysis of MYNN3 indicates a buoyancy-dominated turbulence generation mechanism, with vertical transport promoting upper-level disturbances. This reveals MYNN3’s greater sensitivity to wildfire thermal perturbations and more complete feedback processes, providing a scientific basis for selecting PBL schemes in mountainous wildfire simulations.

Wildfires can significantly enhance surface sensible heat and modify the state of the near-surface atmosphere, becoming key factors in triggering turbulence and restructuring the boundary layer. This study uses high-resolution simulations with WRF-Fire, combined with hourly observational data from six meteorological stations (five national and one emergency stations) during the Jinyun Mountain wildfire in Chongqing, China, to systematically evaluate the performance of five planetary boundary layer (PBL) schemes (MYJ, MYNN2, MYNN3, BouLac, UW) in simulating temperature, wind speed, and turbulence intensity. Results show that all schemes can reproduce the diurnal trends of temperature and wind speed but exhibit significant differences in amplitude response and simulation errors. The MYNN3 scheme captures the spatiotemporal variations of turbulence intensity and wind speed at different heights more accurately, thereby better representing the 2-meter temperature and 10-meter wind speed response and reduces the model’s cold bias in high-temperature simulations. The BouLac and MYNN2 schemes also show some response to thermal disturbances at certain sites but perform poorly under strong perturbations and exhibit large fluctuations. The MYJ and UW schemes show overall weaker turbulence and fail to capture local circulation variations effectively. Turbulent energy budget analysis of MYNN3 indicates a buoyancy-dominated turbulence generation mechanism, with vertical transport promoting upper-level disturbances. This reveals MYNN3’s greater sensitivity to wildfire thermal perturbations and more complete feedback processes, providing a scientific basis for selecting PBL schemes in mountainous wildfire simulations.

Climate change is already significantly affecting the frequency of wildfires in most regions of the world, and the risk of wildfires is expected to amplify further with global warming. Accordingly, there is growing concern about the mechanisms and impacts of extreme fires. In this study, a coupling of the Weather Research and Forecasting model and the Rothermel Fire model (WRF-Fire) is employed to reproduce the spread of fire within the national boundary of inner Mongolia from 21 to 27 May 2009. Simulations were run with or without feedback from fire-to-atmosphere models, and the study focused on how the energy flux of simulated fires changes the local meteorological environment. The coupled simulation could reproduce the burned area well, and the wind speed was the dominant factor in the fire spread, with a maximum value no more than 6.4 m/s, when the terrain height changes little and the proportion of grassland is low. After the feedback, the propagation speed of the fire accelerated, accompanying the release of latent and sensible heat, and local circulation formed near the front of the fire, leading to a convergence and divergence zone in the downwind area. It is worth noting that during a period of more than 140 h of simulation, the area of the fire field increased by 17% from ignition time. Therefore, considering the fire–atmosphere interaction is necessary for accurately predicting fire behavior.

Changes in large-scale circulation, especially El Niño–Southern Oscillation (ENSO), have significant impacts on dust activities over the dust source and downwind regions. However, these impacts present an interdecadal pattern, and it remains less clear which factors lead to the interdecadal variability of the ENSO impact on dust activities over northwestern South Asia, although previous studies have discussed the response of interannual dust activities over northwestern South Asia to the ENSO circle. Based on the linear regression model and MERRA-2 atmospheric aerosol reanalysis data, this study investigated the interdecadal variability of the ENSO impact on dust activities as well as the associated possible atmospheric drivers under two different warming phases over northwestern South Asia. Results indicated that the relationship between ENSO and dust column mass density (DUCMASS) experienced an obvious shift from the accelerated global warming period (1982–1996) to the warming hiatus period (2000–2014). The change in Atlantic and Indian Ocean sea surface temperature anomaly (SSTA) patterns weakened the impact of ENSO on dust activities over northwestern South Asia during 1982–1996, while the change in Pacific Decadal Oscillation (PDO) strengthened ENSO's effect when it was in phase with ENSO. Both the Atlantic and Indian Ocean SSTA patterns were modulated by the duration of ENSO events (i.e., continuing and emerging ENSO). This study provides new insights into numerical simulation involving the influence of atmospheric teleconnections on the variability of dust activities and their influence mechanisms.