Charles H. Fite

Prescribed wildland and agricultural fires are common in the eastern United States (U.S.), but their small size and short durations have led polar‐orbiting satellite data sets to underestimate their emissions due to omission. The higher temporal resolution of the GOES‐16 Advanced Baseline Imager (ABI) improves fire detection, enabling development of a new biomass burning emissions inventory: GOES Eastern U.S. Fire Emissions (GEUFE, pronounced “goofy”). GEUFE is based on geostationary fire radiative power (FRP) observations, incorporates improved crop type classification for agricultural fires, and includes a new emission factor (EF) compilation for 16 land cover types in the eastern U.S., including forest, crop, and grassland types that differ markedly from globally reported EF values. GEUFE provides daily estimates of dry matter (DM) consumption and emissions of CO ₂ , CO, NO _x , NH ₃ , SO ₂ , organic carbon (OC), black carbon (BC), and fine particulate matter (PM _2.5 ) at 2 km resolution. An intercomparison of 10 biomass burning emissions inventories (GEUFE, GBBEPx, QFED, NEI‐2017, RAVE, FEER, VFEI, GFAS, FINN, GFED) showed that OC estimates in the eastern U.S. during August 2019–July 2020 ranged from 0.05 to 1.32 Tg yr ⁻¹ , with both EFs and DM consumption driving the large spread in aerosol estimates. GEUFE, at 0.64 Tg yr ⁻¹ , is at the high end of this range due both to region‐specific EFs and continuous GOES‐16 monitoring, reducing missed short‐lived fires. GEUFE is a process‐based inventory that eliminates reliance on empirical scaling factors, such as QFED's aerosol optical depth‐based adjustments, while explaining previously inferred “missing emissions” from small fires.

Prescribed wildland and agricultural fires are common in the eastern United States (U.S.), but their small size and short durations have led polar-orbiting satellite datasets to underestimate their emissions due to omission. The higher temporal resolution of the GOES-16 Advanced Baseline Imager (ABI) improves fire detection, enabling development of a new biomass burning emissions inventory: GOES Eastern U.S. Fire Emissions (GEUFE, pronounced “goofy”). GEUFE is based on geostationary fire radiative power (FRP) observations, incorporates improved crop type classification for agricultural fires, and includes a new emission factor (EF) compilation for 16 land cover types in the eastern U.S., including forest, crop, and grassland types that differ markedly from globally reported EF values. GEUFE provides daily estimates of dry matter (DM) consumption and emissions of CO2, CO, NOx, NH3, SO2, organic carbon (OC), black carbon (BC), and fine particulate matter (PM2.5) at 2 km resolution. An intercomparison of nine biomass burning emissions inventories (GEUFE, GBBEPx, QFED, NEI-2017, FEER, VFEI, GFAS, FINN, GFED) showed that OC estimates in the eastern U.S. during August 2019–July 2020 ranged from 0.05 to 1.32 Tg yr-1, with both EFs and DM consumption driving the large spread in aerosol estimates. GEUFE, at 0.64 Tg yr-1, is at the high end of this range due both to region-specific EFs and continuous GOES-16 monitoring, reducing missed short-lived fires. GEUFE is a process-based inventory that eliminates reliance on empirical scaling factors, such as QFED’s aerosol optical depth-based adjustments, while explaining previously inferred “missing emissions” from small fires.

Marine emissions of dimethyl sulfide (DMS) and the subsequent formation of its oxidation products methane sulfonic acid (MSA) and sulfuric acid (H₂SO₄) are well-known natural precursors of atmospheric aerosols, contributing to particle mass and cloud formation over ocean and coastal regions. Despite a long-recognized and well-studied role in the marine troposphere, DMS oxidation chemistry remains a work in progress within many current air quality and climate models, with recent advances exploring heterogeneous chemistry and uncovering previously unknown intermediate species. With the identification of additional DMS oxidation pathways and intermediate species influencing its eventual fate, it is important to understand the impact of these pathways on the overall sulfate aerosol budget and aerosol size distribution. In this work, we update and evaluate the DMS oxidation mechanism of the chemical transport model GEOS-Chem by implementing expanded DMS oxidation pathways into the model. These updates include gas- and aqueous-phase reactions, the formation of the intermediates dimethyl sulfoxide (DMSO) and methane sulphinic acid (MSIA), as well as cloud loss and aerosol uptake of the recently quantified intermediate hydroperoxymethyl thioformate (HPMTF). We find that this updated mechanism collectively decreases the global mean surface-layer gas-phase sulfur dioxide (SO₂) mixing ratio by 38 % and enhances sulfate aerosol (SO₄^2-) mixing ratio by 16 %. We further perform sensitivity analyses exploring the contribution of cloud loss and aerosol uptake of HPMTF to the overall sulfur budget. Comparing modeled concentrations to available observations we find improved biases relative to previous studies. To quantify impacts of these chemistry updates on global particle size distributions and mass concentration we use the TOMAS aerosol microphysics module, finding changes in particle formation and growth affect the size distribution of aerosol. With this new DMS-oxidation scheme the global annual mean surface layer number concentration of particles with diameters smaller than 80 nm decreases by 12 %, with cloud loss processes related to HPMTF mostly responsible for this reduction. However, global annual mean number of particles larger than 80 nm increases by 4.5 %, suggesting that the new scheme promotes seasonal particle growth to these sizes capable of acting as cloud condensation nuclei (CCN).

Marine emissions of dimethyl sulfide (DMS) and the subsequent formation of its oxidation products methane sulfonic acid (MSA) and sulfuric acid (H₂SO₄) are well-known natural precursors of atmospheric aerosols, contributing to particle mass and cloud formation over ocean and coastal regions. Despite a long-recognized and well-studied role in the marine troposphere, DMS oxidation chemistry remains a work in progress within many current air quality and climate models, with recent advances exploring heterogeneous chemistry and uncovering previously unknown intermediate species. With the identification of additional DMS oxidation pathways and intermediate species influencing its eventual fate, it is important to understand the impact of these pathways on the overall sulfate aerosol budget and aerosol size distribution. In this work, we update and evaluate the DMS oxidation mechanism of the chemical transport model GEOS-Chem by implementing expanded DMS oxidation pathways into the model. These updates include gas- and aqueous-phase reactions, the formation of the intermediates dimethyl sulfoxide (DMSO) and methane sulphinic acid (MSIA), as well as cloud loss and aerosol uptake of the recently quantified intermediate hydroperoxymethyl thioformate (HPMTF). We find that this updated mechanism collectively decreases the global mean surface-layer gas-phase sulfur dioxide (SO₂) mixing ratio by 38 % and enhances sulfate aerosol (SO₄^2-) mixing ratio by 16 %. We further perform sensitivity analyses exploring the contribution of cloud loss and aerosol uptake of HPMTF to the overall sulfur budget. Comparing modeled concentrations to available observations we find improved biases relative to previous studies. To quantify impacts of these chemistry updates on global particle size distributions and mass concentration we use the TOMAS aerosol microphysics module, finding changes in particle formation and growth affect the size distribution of aerosol. With this new DMS-oxidation scheme the global annual mean surface layer number concentration of particles with diameters smaller than 80 nm decreases by 12 %, with cloud loss processes related to HPMTF mostly responsible for this reduction. However, global annual mean number of particles larger than 80 nm increases by 4.5 %, suggesting that the new scheme promotes seasonal particle growth to these sizes capable of acting as cloud condensation nuclei (CCN).

Marine emissions of dimethyl sulfide (DMS) and the subsequent formation of its oxidation products methane sulfonic acid (MSA) and sulfuric acid (H₂SO₄) are well-known natural precursors of atmospheric aerosols, contributing to particle mass and cloud formation over ocean and coastal regions. Despite a long-recognized and well-studied role in the marine troposphere, DMS oxidation chemistry remains a work in progress within many current air quality and climate models, with recent advances exploring heterogeneous chemistry and uncovering previously unknown intermediate species. With the identification of additional DMS oxidation pathways and intermediate species influencing its eventual fate, it is important to understand the impact of these pathways on the overall sulfate aerosol budget and aerosol size distribution. In this work, we update and evaluate the DMS oxidation mechanism of the chemical transport model GEOS-Chem by implementing expanded DMS oxidation pathways into the model. These updates include gas- and aqueous-phase reactions, the formation of the intermediates dimethyl sulfoxide (DMSO) and methane sulphinic acid (MSIA), as well as cloud loss and aerosol uptake of the recently quantified intermediate hydroperoxymethyl thioformate (HPMTF). We find that this updated mechanism collectively decreases the global mean surface-layer gas-phase sulfur dioxide (SO₂) mixing ratio by 38 % and enhances sulfate aerosol (SO₄^2-) mixing ratio by 16 %. We further perform sensitivity analyses exploring the contribution of cloud loss and aerosol uptake of HPMTF to the overall sulfur budget. Comparing modeled concentrations to available observations we find improved biases relative to previous studies. To quantify impacts of these chemistry updates on global particle size distributions and mass concentration we use the TOMAS aerosol microphysics module, finding changes in particle formation and growth affect the size distribution of aerosol. With this new DMS-oxidation scheme the global annual mean surface layer number concentration of particles with diameters smaller than 80 nm decreases by 12 %, with cloud loss processes related to HPMTF mostly responsible for this reduction. However, global annual mean number of particles larger than 80 nm increases by 4.5 %, suggesting that the new scheme promotes seasonal particle growth to these sizes capable of acting as cloud condensation nuclei (CCN).

Marine emissions of dimethyl sulfide (DMS) and the subsequent formation of its oxidation products methane sulfonic acid (MSA) and sulfuric acid (H₂SO₄) are well-known natural precursors of atmospheric aerosols, contributing to particle mass and cloud formation over ocean and coastal regions. Despite a long-recognized and well-studied role in the marine troposphere, DMS oxidation chemistry remains a work in progress within many current air quality and climate models, with recent advances exploring heterogeneous chemistry and uncovering previously unknown intermediate species. With the identification of additional DMS oxidation pathways and intermediate species influencing its eventual fate, it is important to understand the impact of these pathways on the overall sulfate aerosol budget and aerosol size distribution. In this work, we update and evaluate the DMS oxidation mechanism of the chemical transport model GEOS-Chem by implementing expanded DMS oxidation pathways into the model. These updates include gas- and aqueous-phase reactions, the formation of the intermediates dimethyl sulfoxide (DMSO) and methane sulphinic acid (MSIA), as well as cloud loss and aerosol uptake of the recently quantified intermediate hydroperoxymethyl thioformate (HPMTF). We find that this updated mechanism collectively decreases the global mean surface-layer gas-phase sulfur dioxide (SO₂) mixing ratio by 38 % and enhances sulfate aerosol (SO₄^2-) mixing ratio by 16 %. We further perform sensitivity analyses exploring the contribution of cloud loss and aerosol uptake of HPMTF to the overall sulfur budget. Comparing modeled concentrations to available observations we find improved biases relative to previous studies. To quantify impacts of these chemistry updates on global particle size distributions and mass concentration we use the TOMAS aerosol microphysics module, finding changes in particle formation and growth affect the size distribution of aerosol. With this new DMS-oxidation scheme the global annual mean surface layer number concentration of particles with diameters smaller than 80 nm decreases by 12 %, with cloud loss processes related to HPMTF mostly responsible for this reduction. However, global annual mean number of particles larger than 80 nm increases by 4.5 %, suggesting that the new scheme promotes seasonal particle growth to these sizes capable of acting as cloud condensation nuclei (CCN).

Marine emissions of dimethyl sulfide (DMS) and the subsequent formation of its oxidation products methane sulfonic acid (MSA) and sulfuric acid (H₂SO₄) are well-known natural precursors of atmospheric aerosols, contributing to particle mass and cloud formation over ocean and coastal regions. Despite a long-recognized and well-studied role in the marine troposphere, DMS oxidation chemistry remains a work in progress within many current air quality and climate models, with recent advances exploring heterogeneous chemistry and uncovering previously unknown intermediate species. With the identification of additional DMS oxidation pathways and intermediate species influencing its eventual fate, it is important to understand the impact of these pathways on the overall sulfate aerosol budget and aerosol size distribution. In this work, we update and evaluate the DMS oxidation mechanism of the chemical transport model GEOS-Chem by implementing expanded DMS oxidation pathways into the model. These updates include gas- and aqueous-phase reactions, the formation of the intermediates dimethyl sulfoxide (DMSO) and methane sulphinic acid (MSIA), as well as cloud loss and aerosol uptake of the recently quantified intermediate hydroperoxymethyl thioformate (HPMTF). We find that this updated mechanism collectively decreases the global mean surface-layer gas-phase sulfur dioxide (SO₂) mixing ratio by 38 % and enhances sulfate aerosol (SO₄^2-) mixing ratio by 16 %. We further perform sensitivity analyses exploring the contribution of cloud loss and aerosol uptake of HPMTF to the overall sulfur budget. Comparing modeled concentrations to available observations we find improved biases relative to previous studies. To quantify impacts of these chemistry updates on global particle size distributions and mass concentration we use the TOMAS aerosol microphysics module, finding changes in particle formation and growth affect the size distribution of aerosol. With this new DMS-oxidation scheme the global annual mean surface layer number concentration of particles with diameters smaller than 80 nm decreases by 12 %, with cloud loss processes related to HPMTF mostly responsible for this reduction. However, global annual mean number of particles larger than 80 nm increases by 4.5 %, suggesting that the new scheme promotes seasonal particle growth to these sizes capable of acting as cloud condensation nuclei (CCN).

Marine emissions of dimethyl sulfide (DMS) and the subsequent formation of its oxidation products methane sulfonic acid (MSA) and sulfuric acid (H₂SO₄) are well-known natural precursors of atmospheric aerosols, contributing to particle mass and cloud formation over ocean and coastal regions. Despite a long-recognized and well-studied role in the marine troposphere, DMS oxidation chemistry remains a work in progress within many current air quality and climate models, with recent advances exploring heterogeneous chemistry and uncovering previously unknown intermediate species. With the identification of additional DMS oxidation pathways and intermediate species influencing its eventual fate, it is important to understand the impact of these pathways on the overall sulfate aerosol budget and aerosol size distribution. In this work, we update and evaluate the DMS oxidation mechanism of the chemical transport model GEOS-Chem by implementing expanded DMS oxidation pathways into the model. These updates include gas- and aqueous-phase reactions, the formation of the intermediates dimethyl sulfoxide (DMSO) and methane sulphinic acid (MSIA), as well as cloud loss and aerosol uptake of the recently quantified intermediate hydroperoxymethyl thioformate (HPMTF). We find that this updated mechanism collectively decreases the global mean surface-layer gas-phase sulfur dioxide (SO₂) mixing ratio by 38 % and enhances sulfate aerosol (SO₄^2-) mixing ratio by 16 %. We further perform sensitivity analyses exploring the contribution of cloud loss and aerosol uptake of HPMTF to the overall sulfur budget. Comparing modeled concentrations to available observations we find improved biases relative to previous studies. To quantify impacts of these chemistry updates on global particle size distributions and mass concentration we use the TOMAS aerosol microphysics module, finding changes in particle formation and growth affect the size distribution of aerosol. With this new DMS-oxidation scheme the global annual mean surface layer number concentration of particles with diameters smaller than 80 nm decreases by 12 %, with cloud loss processes related to HPMTF mostly responsible for this reduction. However, global annual mean number of particles larger than 80 nm increases by 4.5 %, suggesting that the new scheme promotes seasonal particle growth to these sizes capable of acting as cloud condensation nuclei (CCN).

Marine emissions of dimethyl sulfide (DMS) and the subsequent formation of its oxidation products methane sulfonic acid (MSA) and sulfuric acid (H₂SO₄) are well-known natural precursors of atmospheric aerosols, contributing to particle mass and cloud formation over ocean and coastal regions. Despite a long-recognized and well-studied role in the marine troposphere, DMS oxidation chemistry remains a work in progress within many current air quality and climate models, with recent advances exploring heterogeneous chemistry and uncovering previously unknown intermediate species. With the identification of additional DMS oxidation pathways and intermediate species influencing its eventual fate, it is important to understand the impact of these pathways on the overall sulfate aerosol budget and aerosol size distribution. In this work, we update and evaluate the DMS oxidation mechanism of the chemical transport model GEOS-Chem by implementing expanded DMS oxidation pathways into the model. These updates include gas- and aqueous-phase reactions, the formation of the intermediates dimethyl sulfoxide (DMSO) and methane sulphinic acid (MSIA), as well as cloud loss and aerosol uptake of the recently quantified intermediate hydroperoxymethyl thioformate (HPMTF). We find that this updated mechanism collectively decreases the global mean surface-layer gas-phase sulfur dioxide (SO₂) mixing ratio by 38 % and enhances sulfate aerosol (SO₄^2-) mixing ratio by 16 %. We further perform sensitivity analyses exploring the contribution of cloud loss and aerosol uptake of HPMTF to the overall sulfur budget. Comparing modeled concentrations to available observations we find improved biases relative to previous studies. To quantify impacts of these chemistry updates on global particle size distributions and mass concentration we use the TOMAS aerosol microphysics module, finding changes in particle formation and growth affect the size distribution of aerosol. With this new DMS-oxidation scheme the global annual mean surface layer number concentration of particles with diameters smaller than 80 nm decreases by 12 %, with cloud loss processes related to HPMTF mostly responsible for this reduction. However, global annual mean number of particles larger than 80 nm increases by 4.5 %, suggesting that the new scheme promotes seasonal particle growth to these sizes capable of acting as cloud condensation nuclei (CCN).