A novel framework for assessing regional wildfires contributions to biomass burning aerosol optical depth

<p>Biomass burning (BB) aerosols can influence regional and global climate through interactions with radiation, clouds, and precipitation. Here, we investigate the impact of BB aerosols on the energy balance and hydrological cycle over the Amazon Basin during the dry season. We performed WRF-Chem simulations for a range of different BB emission scenarios to explore and characterize nonlinear effects and individual contributions from aerosol–radiation interactions (ARIs) and aerosol–cloud interactions (ACIs). For scenarios representing the lower and upper limits of BB emission estimates for recent years (2002–2016), we obtained total regional BB aerosol radiative forcings of -0.2 and 1.5Wm<sup>-2</sup>, respectively, showing that the influence of BB aerosols on the regional energy balance can range from modest cooling to strong warming. We find that ACIs dominate at low BB emission rates and low aerosol optical depth (AOD), leading to an increased cloud liquid water path (LWP) and negative radiative forcing, whereas ARIs dominate at high BB emission rates and high AOD, leading to a reduction of LWP and positive radiative forcing. In all scenarios, BB aerosols led to a decrease in the frequency of occurrence and rate of precipitation, caused primarily by ACI effects at low aerosol loading and by ARI effects at high aerosol loading. Overall, our results show that ACIs tend to saturate at high aerosol loading, whereas the strength of ARIs continues to increase and plays a more important role in highly polluted episodes and regions. This should hold not only for BB aerosols over the Amazon, but also for other light-absorbing aerosols such as fossil fuel combustion aerosols in industrialized and densely populated areas. The importance of ARIs at high aerosol loading highlights the need for accurately characterizing aerosol optical properties in the investigation of aerosol effects on clouds, precipitation, and climate.</p>

Abstract. Biomass burning (BB) aerosols can influence regional and global climate through interactions with radiation, clouds, and precipitation. Here, we investigate the impact of BB aerosols on the energy balance and hydrological cycle over the Amazon Basin during the dry season. We performed simulations with a fully coupled meteorology–chemistry model, the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), for a range of different BB emission scenarios to explore and characterize nonlinear effects and individual contributions from aerosol–radiation interactions (ARIs) and aerosol–cloud interactions (ACIs). The ARIs of BB aerosols tend to suppress low-level liquid clouds by local warming and increased evaporation and to facilitate the formation of high-level ice clouds by enhancing updrafts and condensation at high altitudes. In contrast, the ACIs of BB aerosol particles tend to enhance the formation and lifetime of low-level liquid clouds by providing more cloud condensation nuclei (CCN) and to suppress the formation of high-level ice clouds by reducing updrafts and condensable water vapor at high altitudes (>8 km). For scenarios representing the lower and upper limits of BB emission estimates for recent years (2002–2016), we obtained total regional BB aerosol radiative forcings of −0.2 and 1.5 W m−2, respectively, showing that the influence of BB aerosols on the regional energy balance can range from modest cooling to strong warming. We find that ACIs dominate at low BB emission rates and low aerosol optical depth (AOD), leading to an increased cloud liquid water path (LWP) and negative radiative forcing, whereas ARIs dominate at high BB emission rates and high AOD, leading to a reduction of LWP and positive radiative forcing. In all scenarios, BB aerosols led to a decrease in the frequency of occurrence and rate of precipitation, caused primarily by ACI effects at low aerosol loading and by ARI effects at high aerosol loading. The dependence of precipitation reduction on BB aerosol loading is greater in a strong convective regime than under weakly convective conditions. Overall, our results show that ACIs tend to saturate at high aerosol loading, whereas the strength of ARIs continues to increase and plays a more important role in highly polluted episodes and regions. This should hold not only for BB aerosols over the Amazon, but also for other light-absorbing aerosols such as fossil fuel combustion aerosols in industrialized and densely populated areas. The importance of ARIs at high aerosol loading highlights the need for accurately characterizing aerosol optical properties in the investigation of aerosol effects on clouds, precipitation, and climate.

The radiative forcing associated with biomass burning aerosols has been calculated over West Africa using a chemical transport model. The model simulations focus on the period of January∼February 2006 during the Dust and Biomass‐burning Experiment (DABEX). All of the main aerosol components for this region are modeled including mineral dust, biomass burning (BB) aerosols, secondary organic carbon associated with BB emissions, and carbonaceous particles from the use of fossil fuel and biofuel. The optical properties of the BB aerosol are specified using aircraft data from DABEX. The modeled aerosol optical depth (AOD) is within 15–20% of data from the few available Aerosol Robotic Network (AERONET) measurement stations. However, the model predicts very high AOD over central Africa, which disagrees somewhat with satellite retrieved AOD from Moderate Resolution Imaging Spectroradiometer (MODIS) and Multiangle Imaging Spectroradiometer (MISR). This indicates that BB emissions may be too high in central Africa or that very high AOD may be incorrectly screened out of the satellite data. The aerosol single scattering albedo increases with wavelength in our model and in AERONET retrievals, which contrasts with results from a previous biomass burning aerosol campaign. The model gives a strong negative radiative forcing of the BB aerosols at the top of the atmosphere (TOA) in clear‐sky conditions over most of the domain, except over the Saharan desert where surface albedos are high. The all‐sky TOA radiative forcing is quite inhomogeneous with values varying from −10 to 10 W m−2. The regional mean TOA radiative forcing is close to zero for the all‐sky calculation and around −1.5 W m−2 for the clear‐sky calculation. Sensitivity simulations indicate a positive regional mean TOA radiative forcing of up to 3 W m−2.

Abstract. As criteria pollutants from anthropogenic emissions have declined in the US in the last 2 decades, biomass burning (BB) emissions are becoming more important for urban air quality. Tracking the transported BB emissions and their impacts is challenging, especially in areas that are also burdened by anthropogenic sources like the Texas Gulf Coast. During the Corpus Christi and San Antonio (CCSA) field campaign in spring 2021, two long-range-transport BB events (BB1 and BB2) were identified. The observed patterns of an absorption Ångström exponent (AAE), a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) BB tracer (f60), equivalent black carbon (eBC), acetonitrile and carbon monoxide (CO) during BB1 and BB2 indicated differences in the mixing of transported BB plumes with local anthropogenic sources. The combined information from HYSPLIT backward-trajectory (BT) and satellite observations revealed that BB1 had mixed influence of transported smoke plumes from fires in central Mexico, the Yucatán Peninsula and the central US, whereas BB2 was influenced by fires in the central US. The estimated transport times of smoke from the Mexican fires and the central US fires to our study site were not too different (48–54 and 24–36 h, respectively), and both events appeared to have undergone similar levels of atmospheric processing, as evident in the elemental ratios of bulk organic aerosol (OA). We observed an aging trend for f44 vs. f60 and f44 vs. f43 as a function of time during BB2 but not during BB1. Positive matrix factorization (PMF) analysis of OA showed that BB1 had a mixture of organics from aged BB emissions with an anthropogenic marine signal, while the oxidized organic compounds from aged BB emissions dominated the aerosols during BB2. The size distribution of aerosol composition revealed distinct characteristics between BB1 and BB2, where BB1 was found to be externally mixed, exhibiting a combination of BB and anthropogenic marine aerosols. On the other hand, BB2 exhibited internal mixing dominated by aged BB aerosol. Our analysis from mobile and stationary measurements highlights that both CO and acetonitrile are likely impacted by local sources even during the BB events and specifically that acetonitrile cannot be used as a unique BB tracer for dilute BB plumes in an industrially influenced location. A suitable volatile organic compound (VOC) tracer would need to be emitted in high concentrations during BB, resistant to degradation during transport, unique to BB and able to be measured in the field. This study effectively demonstrates that AAE and aerosol BB tracers served as precise and effective tracers in these complex emission scenarios. Network deployment of multiwavelength photometers holds promise for enhancing our understanding of BB impacts on air quality and supporting informed decision-making for effective mitigation strategies in locations with mixed sources and influence of dilute BB plumes. To demonstrate the relevance of such an aerosol optical network, we provide evidence of the potential regional impacts of these transported BB events on urban O3 levels using measurements from the surface air quality monitoring network in Texas.

Impacts of vertical distribution of Southeast Asian biomass burning emissions on aerosol distributions and direct radiative effects over East Asia

Simulations of biomass burning (BB) emissions in global chemistry and aerosol transport models depend on external inventories, which provide location and strength for BB aerosol sources. Our previous work shows that to first order, satellite snapshots of aerosol optical depth (AOD) near the emitted smoke plume can be used to constrain model‐simulated AOD, and effectively, the smoke source strength. We now refine the satellite‐snapshot method and investigate where applying simple multiplicative emission adjustment factors alone to the widely used Global Fire Emission Database version 3 emission inventory can achieve regional‐scale consistency between Moderate Resolution Imaging Spectroradiometer (MODIS) AOD snapshots and the Goddard Chemistry Aerosol Radiation and Transport model. The model and satellite AOD are compared globally, over a set of BB cases observed by the MODIS instrument during the 2004, and 2006–2008 biomass burning seasons. Regional discrepancies between the model and satellite are diverse around the globe yet quite consistent within most ecosystems. We refine our approach to address physically based limitations of our earlier work (1) by expanding the number of fire cases from 124 to almost 900, (2) by using scaled reanalysis‐model simulations to fill missing AOD retrievals in the MODIS observations, (3) by distinguishing the BB components of the total aerosol load from background aerosol in the near‐source regions, and (4) by including emissions from fires too small to be identified explicitly in the satellite observations. The small‐fire emission adjustment shows the complimentary nature of correcting for source strength and adding geographically distinct missing sources. Our analysis indicates that the method works best for fire cases where the BB fraction of total AOD is high, primarily evergreen or deciduous forests. In heavily polluted or agricultural burning regions, where smoke and background AOD values tend to be comparable, this approach encounters large uncertainties, and in some regions, other model‐ or measurement‐related factors might contribute significantly to model‐satellite discrepancies. This work sets the stage for a larger study within the Aerosol Comparison between Observations and Models (AeroCOM) multimodel biomass burning experiment. By comparing multiple model results using the refined technique presented here, we aim to separate BB inventory from model‐specific contributions to the remaining discrepancies.

Abstract. Light-absorbing aerosols emitted during open biomass burning (BB) events such as wildfires and agricultural burns have a strong impact on the Earth's radiation budget through both direct and indirect effects. Additionally, BB aerosols and gas-phase emissions can substantially reduce air quality at local, regional, and global scales, negatively affecting human health. South America is one of largest contributors to BB emissions globally. After Amazonia, the BB emissions from wildfires and agricultural burns in the grassland plains of northern South America (NSA) are the most significant in the region. However, few studies have analyzed the potential impact of NSA BB emissions on regional air quality. Recent evidence suggests that seasonal variations in air quality in several major cities in NSA could be associated with open biomass burning emissions, but it is still uncertain to what extent those sources impact air quality in the region. In this work, we report on 3 years of continuous equivalent black carbon (eBC) and brown carbon (BrC) observations at a hilltop site located upwind of the city of Bogotá, and we demonstrate its association with fires detected by the MODerate-resolution Imaging Spectroradiometer (MODIS) in a 3000 km × 2000 km domain. Offline PM2.5 filter samples collected during three field campaigns were analyzed to quantify water-soluble organic carbon (WSOC), organic and elemental carbon (OC∕EC), and biomass burning tracers such as levoglucosan, galactosan, and potassium. MODIS active fire data and HYSPLIT back trajectories were used to identify potential biomass burning plumes transported to the city. We analyzed the relationship between BrC, WSOC, water-soluble potassium, and levoglucosan to identify signals of the regional transport of BB aerosols. Our results confirm that regional biomass burning transport from wildfires occurs annually during the months of January and April. The seasonality of eBC closely followed that of PM2.5 at the city air quality stations; however, the observed seasonality of BrC is distinctly different to that of eBC and strongly associated with regional fire counts. The strong correlation between BrC and regional fire counts was observed at daily, weekly, and monthly timescales. WSOC at the measurement site was observed to increase linearly with levoglucosan during high BB periods and to remain constant at ∼2.5 µgC m−3 during the low BB seasons. Our findings show, for the first time in this region, that aged BB plumes can regularly reach densely populated areas in the Central Andes of northern South America. A source footprint analysis involving BrC observations, back trajectories, and remotely sensed fire activity shows that the eastern savannas in NSA are the main BB source region for the domain analyzed.

Abstract. Atmospheric aerosol distributions from 2000 to 2007 are simulated with the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model to attribute light absorption by aerosol to its composition and sources from pollution, dust, and biomass burning. The 8-year, global averaged total aerosol optical depth (τ), absorption optical depth (τa), and single scattering albedo (ω) at 550 nm are estimated at 0.14, 0.0086, and 0.95, respectively, with sulfate making the largest fraction of τ (37%), followed by dust (30%), sea salt (16%), organic matter (OM) (13%), and black carbon (BC) (4%). BC and dust account for 43% and 53% of τa, respectively. From a model experiment with "tagged" sources, natural aerosols are estimated to be 58% of τ and 53% of τa, with pollution and biomass burning aerosols to share the rest. Comparing with data from the surface sunphotometer network AERONET, the model tends to reproduce much better the AERONET direct measured data of τ and the Ångström exponent (α) than its retrieved quantities of ω and τa. Relatively small in its systematic bias of τ for pollution and dust regions, the model tends to underestimate τ for biomass burning aerosols by 30–40%. The modeled α is 0.2–0.3 too low (particle too large) for pollution and dust aerosols but 0.2–0.3 too high (particle too small) for the biomass burning aerosols, indicating errors in particle size distributions in the model. Still, the model estimated ω is lower in dust regions and shows a much stronger wavelength dependence for biomass burning aerosols but a weaker one for pollution aerosols than those quantities from AERONET. These comparisons necessitate model improvements on aerosol size distributions, the refractive indices of dust and black carbon aerosols, and biomass burning emissions in order to better quantify the aerosol absorption in the atmosphere.

The Biomass Burning Aerosol Campaign (BiBAC) was conducted in the Kruger National Park (KNP), at Skukuza in South Africa during the 2022 biomass burning season. The campaign included an Intensive Observation Phase (IOP) from September to October, aiming to quantify aerosol optical properties and plume transport.(Ranaivombola et al., 2024). The combination of ground-based (sun-photometer), satellite observations (MODIS, IASI and CALIOP), and CAMS reanalysis show a significant aerosol and carbon monoxide (CO) loading linked to biomass burning activity. Using AOD data from sun-photometer observations, Ranaivombola et al., (2024) define two events of biomass burning plume over the Southwestern Indian Ocean (SWIO) basin: September 18 to 23 and October 9 to 17, called here after event 1 and event 2, respectively.During Event 1, the plume was transported toward the SWIO basin as a "river of smoke" phenomenon. As reported previously in the literature (Swap et al., 2003 and Flamant et al., 2022), the meteorological conditions were influenced by the passage of westerly waves associated with a cut-off low (COL) that favored the eastern transport pathway. However, it was not the case during Event 1. There were two troughs which supported the formation of two frontal systems and contributed to the transport of aerosols and CO plumes from South America (SAm) towards Southern Africa (SA). This transport was driven by a westerly baroclinic wave through the mid-tropospheric layers.Event 2 involved a more complex synoptic setup with three frontal systems supported by three distinct troughs, allowing the recirculation of plumes over SA. This dynamic system enhanced the transport of CO plumes from SAm, which merged with African plumes over the Mozambique Channel. The sustained activity of the baroclinic wave generated new troughs, keeping aerosol levels high for an extended period of 1.5 week. The progression of baroclinic waves and frontal system development were essential in driving regional and intercontinental transport of aerosols and CO plumes.These two events allowed to reveal two transport mechanisms of aerosol plumes and CO between SAm and SA towards the SWIO basin. It shows also that SA is a target region for aerosols and CO from SAm biomass burning. To assess and quantify the contributions of SA and SAm sources to observed CO concentrations over SA, we used the FLEXPART model (version 10.4) coupled with CO emissions database (biomass burning and anthropogenic emission from CAMS: GFAS and CAMS-GLOB-ANT, respectively). Each simulation tracked particles representing CO back in time over a period of 20 days, during the IOP. The setup included daily releases of 20,000 particles over six sites in Southern Africa (Skukuza, Durban, Maun, Upington, Mongu and Gobabeb). Both SA and SAm sources significantly influenced the CO balance over SA. The contribution of biomass burning emissions from SA were higher than those from SAm. Nevertheless, the biomass burning emission from SAm were more variable and could occasionally match or exceed those from SA. This quantification confirmed the predominance of African sources but also highlighted the presence of intercontinental transport which is poorly investigated until now.

In the wet season, a large portion of the Amazon region constitutes one of the most pristine continental areas, with very low concentrations of atmospheric trace gases and aerosol particles. However, land use change modifies the biosphere-atmosphere interactions in such a way that key processes that maintain the functioning of Amazonia are substantially altered. This study presents a comparison between aerosol properties observed at a preserved forest site in Central Amazonia (TT34 North of Manaus) and at a heavily biomass burning impacted site in south-western Amazonia (PVH, close to Porto Velho). Amazonian aerosols were characterized in detail, including aerosol size distributions, aerosol light absorption and scattering, optical depth and aerosol inorganic and organic composition, among other properties. The central Amazonia site (TT34) showed low aerosol concentrations (PM2.5 of 1.3 +/- 0.7 microg m(-3) and 3.4 +/- 2.0 microg m(-3) in the wet and dry seasons, respectively), with a median particle number concentration of 220 cm(-3) in the wet season and 2200 cm(-3) in the dry season. At the impacted site (PVH), aerosol loadings were one order of magnitude higher (PM2.5 of 10.2 +/- 9.0 microg m(-3) and 33.0 +/- 36.0 microg m(-3) in the wet and dry seasons, respectively). The aerosol number concentration at the impacted site ranged from 680 cm(-3) in the wet season up to 20 000 cm(-3) in the dry season. An aerosol chemical speciation monitor (ACSM) was deployed in 2013 at both sites, and it shows that organic aerosol account to 81% to the non-refractory PM1 aerosol loading at TT34, while biomass burning aerosols at PVH shows a 93% content of organic particles. Three years of filter-based elemental composition measurements shows that sulphate at the impacted site decreases, on average, from 12% of PM2.5 mass during the wet season to 5% in the dry season. This result corroborates the ACSM finding that the biomass burning contributed overwhelmingly to the organic fine mode aerosol during the dry season in this region. Aerosol light scattering and absorption coefficients at the TT34 site were low during the wet season, increasing by a factor of 5, approximately, in the dry season due to long range transport of biomass burning aerosols reaching the forest site in the dry season. Aerosol single scattering albedo (SSA) ranged from 0.84 in the wet season up to 0.91 in the dry. At the PVH site, aerosol scattering coefficients were 3-5 times higher in comparison to the TT34 site, an indication of strong regional background pollution, even in the wet season. Aerosol absorption coefficients at PVH were about 1.4 times higher than at the forest site. Ground-based SSA at PVH was around 0.92 year round, showing the dominance of scattering aerosol particles over absorption, even for biomass burning aerosols. Remote sensing observations from six AERONET sites and from MODIS since 1999, provide a regional and temporal overview. Aerosol Optical Depth (AOD) at 550 nm of less than 0.1 is characteristic of natural conditions over Amazonia. At the perturbed PVH site, AOD550 values greater than 4 were frequently observed in the dry season. Combined analysis of MODIS and CERES showed that the mean direct radiative forcing of aerosols at the top of the atmosphere (TOA) during the biomass burning season was -5.6 +/- 1.7 W m(-2), averaged over whole Amazon Basin. For high AOD (larger than 1) the maximum daily direct aerosol radiative forcing at the TOA was as high as -20 W m(-2) locally. This change in the radiation balance caused increases in the diffuse radiation flux, with an increase of Net Ecosystem Exchange (NEE) of 18-29% for high AOD. From this analysis, it is clear that land use change in Amazonia shows alterations of many atmospheric properties, and these changes are affecting the functioning of the Amazonian ecosystem in significant ways.

Simulations of biomass burning (BB) emissions in chemistry transport models strongly depend on the inventories that define emission source location and strength. We use 13 global biomass burning emission estimates, including the widely used Global Fire Emission Database (GFED) monthly and daily versions, Fire Radiative Power (FRP)‐based Quick Fire Emission Data set QFED, and 11 calculated emissions from different combinations of burned area based on the Moderate Resolution Imaging Spectroradiometer (MODIS) products, effective fuel load, and species emission factors as alternative inputs to the global Goddard Chemistry Aerosol Radiation and Transport (GOCART) model. The resultant simulated aerosol optical depth (AOD) and its spatial distribution are compared to AOD snapshots measured by the MODIS instrument for 124 fire events occurring between 2006 and 2007. This comparison exposes the regional biases of each emission option. GOCART average fire AOD values compare best to MODIS‐measured AOD when the daily GFED inventory is used as input to GOCART. Even though GFED‐based emission options provide the lowest emissions in the tropics, GFED‐based GOCART AOD compares best with MODIS AOD in tropical cases. Fire‐counts‐based emission options give the largest emission estimates in the boreal regions, and the model performs best at higher latitudes with these inputs when compared to MODIS. Comparison of total annual BB emissions by all inventories suggests that burned area estimates are usually the largest source of disagreement. It is also shown that the quantitative relationship between BB aerosol emission rate and model‐simulated AOD is related to the horizontal plume dispersion, which can be approximated by the wind speed in the planetary boundary layer in most cases. Thus, given average wind speed of the smoke plume environment, MODIS‐measured AOD can provide a constraint to the strength of BB sources at the level of individual plumes.

Study of aerosol optical properties at Kunming in southwest China and long-range transport of biomass burning aerosols from North Burma

In this investigation, the interaction between aerosols derived from biomass burning and dust aerosol is the focus of interest. We have examined the morphology and chemical composition of dust and biomass burning aerosol particles sampled on airborne filters using an environmental scanning electron microscope equipped with both an energy dispersive X‐ray analysis and an image analysis system. Using these techniques, we were able to study both mineral dust and biomass burning particles in samples containing significant amounts of both biomass burning and dust aerosol, compared to samples dominated by biomass burning aerosol and a sample dominated by dust aerosol. Thirteen particle types were classified in the samples. Aluminosilicates were the dominant particle type in the sample dominated by dust aerosol. Many more particles were found to be rich in S, Na, and K in the sample dominated by biomass burning aerosols, and particles in these samples were also found to be completely devoid of Cl due to aging of the aerosol and chemical conversion during atmospheric transport. We suggest that biomass burning particles containing all three characteristic elements are internal mixtures. Particle imaging showed that up to a third of soot particles were internally mixed with mineral dust particles in samples containing significant numbers of both biomass burning and mineral dust particles. This internal mixing would change the optical properties of the particle ensemble and the direct radiative forcing caused by biomass burning significantly.

Abstract. Despite significant advancements in improving the dataset for biomass burning (BB) emissions over the past few decades, uncertainties persist in BB aerosol emissions, impeding the accurate assessment of simulated aerosol optical properties (AOPs) and direct radiative forcing (DRF) during wildfire events in global and regional models. This study assessed AOPs (including aerosol optical depth (AOD), aerosol absorption optical depth (AAOD), and aerosol extinction coefficients (AECs)) and DRF using eight independent BB emission inventories applied to the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) during the BB period (March 2019) in peninsular Southeast Asia (PSEA), where the eight BB emission inventories were the Global Fire Emissions Database version 4.1s (GFED), Fire INventory from NCAR version 1.5 (FINN1.5), the Fire Inventory from NCAR version 2.5 MOS (MODIS fire detections; FINN2.5 MOS), the Fire Inventory from NCAR version 2.5 MOSVIS (MODIS + VIIRS fire detections; FINN2.5 MOSVIS), Global Fire Assimilation System version 1.2s (GFAS), Fire Energetics and Emissions Research version 1.0 (FEER), Quick Fire Emissions Dataset version 2.5 release 1 (QFED), and Integrated Monitoring and Modelling System for Wildland FIRES project version 2.0 (IS4FIRES), respectively. The results show that in the PSEA region, organic carbon (OC) emissions in the eight BB emission inventories differ by a factor of about 9 (0.295–2.533 Tg M−1), with 1.09 ± 0.83 Tg M−1 and a coefficient of variation (CV) of 76 %. High-concentration OC emissions occurred primarily in savanna and agricultural fires. The OC emissions from the GFED and GFAS are significantly lower than the other inventories. The OC emissions in FINN2.5 MOSVIS are approximately twice as high as those in FINN1.5. Sensitivity analysis of AOD simulated by WRF-Chem to different BB emission datasets indicated that the FINN scenarios (v1.5 and 2.5) significantly overestimate AOD compared to observation (VIIRS), while the other inventories underestimate AOD in the high-AOD (HAOD; AOD > 1) regions range from 15–22.5∘ N, 97–110∘ E. Among the eight schemes, IS4FIRES and FINN1.5 performed better in terms of AOD simulation consistency and bias in the HAOD region when compared to AERONET sites. The AAOD in WRF-Chem during the PSEA wildfire period was assessed, using satellite observations (TROPOMI) and AERONET data, and it was found that the AAOD simulated with different BB schemes did not perform as well as the AOD. The significant overestimation of AAOD by FINN (v1.5 and 2.5), FEER, and IS4FIRES schemes in the HAOD region, with the largest overestimation for FINN2.5 MOSVIS. FINN1.5 schemes performed better in representing AAOD at AERONET sites within the HAOD region. The simulated AOD and AAOD from FINN2.5 MOSVIS always show the best correlation with the observations. AECs simulated by WRF-Chem with all the eight BB schemes trends were consistent with CALIPSO in the vertical direction (0.5 to 4 km), demonstrating the efficacy of the smoke plume rise model used in WRF-Chem to simulate smoke plume heights. However, the FINN (v1.5 and 2.5) schemes overestimated AECs, while the other schemes underestimated it. In the HAOD region, BB aerosols exhibited a daytime shortwave radiative forcing of −32.60 ± 24.50 W m−2 at the surface, positive forcing (1.70 ± 1.40 W m−2) in the atmosphere, and negative forcing (−30.89 ± 23.6 W m−2) at the top of the atmosphere. Based on the analysis, FINN1.5 and IS4FIRES are recommended for accurately assessing the impact of BB on air quality and climate in the PSEA region.

Diurnal spatial distributions of aerosol optical and cloud micro-macrophysics properties in Africa based on MODIS observations