Bacterial Emission Factors: A Foundation for the Terrestrial-Atmospheric Modeling of Bacteria Aerosolized by Wildland Fires

Environmental Science & Technology, Год журнала: 2024, Номер 58(5), С. 2413 - 2422

Опубликована: Янв. 24, 2024

Wildland fire is a major global driver in the exchange of aerosols between terrestrial environments and atmosphere. This commonly quantified using emission factors or mass pollutant emitted per fuel burned. However, for microbes aerosolized by have yet to be determined. Using bacterial cell concentrations collected on unmanned aircraft systems over forest fires Utah, USA, we determine (BEFs) first time. We estimate that 1.39 × 10

Язык: Английский

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Characterization of stratospheric particle size distribution uncertainties using SAGE II and SAGE III/ISS extinction spectra

Atmospheric measurement techniques, Год журнала: 2024, Номер 17(7), С. 2025 - 2054

Опубликована: Апрель 9, 2024

Abstract. A new algorithm was developed to infer particle size distribution parameters from the Stratospheric Aerosol and Gas Experiment II (SAGE II) SAGE III on International Space Station III/ISS) extinction spectra using a lookup table (LUT) approach. Here, SAGE-based ratios were matched LUT values, and, these matches, weighted statistics calculated median values higher-moment as well quantify uncertainty in estimates. This carried out by solving for both single-mode bimodal lognormal distributions. The work presented herein falls under two general headings: (1) theoretical study determine accuracy of this methodology, (2) solution applied III/ISS records with brief case analysis 2022 Hunga Tonga eruption. methodology demonstrated be ≈ 25 % accurate mode radius has minor dependence composition. While solutions obtained algorithm, we provide conclusive demonstration how why estimates are inherently unstable alone. Finally, aerosol plume evolved regard transport over 18 months after (PSD) estimates, parameters, uncertainties products within Level 2 (L2) products, currently available download, will merged into main release subsequent L2 release.

Язык: Английский

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Meteorological analysis of an extreme pyroconvective wildfire at Dunalley-Forcett, Australia

Natural Hazards, Год журнала: 2025, Номер unknown

Опубликована: Март 27, 2025

Язык: Английский

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Stratospheric Aerosol Backscatter and Depolarization Ratio Observed With Ground‐Based Lidar at Tsukuba, Japan, and Lauder, New Zealand

Journal of Geophysical Research Atmospheres, Год журнала: 2025, Номер 130(7)

Опубликована: Апрель 3, 2025

Abstract Vertical distributions of stratospheric aerosol backscatter and depolarization ratio (nonsphericity) have been measured using ground‐based lidars at Tsukuba, Japan Lauder, New Zealand. The observational results after 2003 show that the increased several times large volcanic eruptions wildfires. largest increases in vertically integrated backscattering coefficient (IBC) above 16.5 km (IBC ) were observed Raikoke eruption 2019 Tsukuba Australian wildfire 2019/20 Lauder. IBC returned to normal levels 1–2 years. After eruptions, particle (PDR) for days then decreased a few dozen most cases. In contrast, PDR wildfires gradually These suggest ash was quickly removed troposphere or dissolved coated with liquid become non‐depolarizing. smoke stays stratosphere years due its small size mass density. We compare lidar‐derived extinction profiles optical depth (stratospheric (SAOD)) those obtained balloon‐borne counter (OPC), satellite‐borne instruments (SAGE‐II, Cloud‐Aerosol Lidar Orthogonal Polarization (CALIOP), Global Space‐based Stratospheric Aerosol Climatology (GloSSAC)), Meteorological Research Institute Earth System Model (MRI‐ESM2) validation. mean differences from SAOD +15% SAGE‐II, −11% GloSSAC, +32% CALIOP, −44% MRI‐ESM2 +19% +28% OPC, +7% −15% −72%

Язык: Английский

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Viscosity and Phase State of Wildfire Smoke Particles in the Stratosphere from Pyrocumulonimbus Events: An Initial Assessment

Environmental Science & Technology, Год журнала: 2025, Номер unknown

Опубликована: Апрель 17, 2025

Understanding the viscosity and phase state of biomass-burning organic aerosol (BBOA) from wildfires pyrocumulonimbus (pyroCb) events in stratosphere is critical for predicting their role stratospheric multiphase chemistry ozone depletion. However, BBOA under conditions, including interactions with sulfuric acid (H2SO4), remain largely unquantified. In this study, we combine laboratory data a thermodynamic model to predict conditions. Our results suggest that H2SO4-to-BBOA mass ratio 0.37─an estimated upper limit pyroCb smoke lower after two months aging─is highly viscous frequently exists glassy state. Even at higher 0.79─an nine aging─BBOA can still transition certain state, bulk reactions are suppressed, may be limited particle surfaces. We also highlight key areas future research needed better constrain its subsequent impact on ozone.

Язык: Английский

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Occurrence, abundance, and formation of atmospheric tarballs from a wide range of wildfires in the western US

Опубликована: Апрель 15, 2024

Abstract. Biomass burning emits large numbers of organic aerosol particles, a subset which are called tarballs (TBs). TBs possess spherical morphology and unique physical, chemical, optical properties. They recognized as brown carbon thereby having implications for climate through the absorption solar radiation. Aerosol particles were collected from wildfire agricultural fire smoke sampled by NASA DC-8 aircraft during FIREX-AQ campaign in western US July to September 2019. The current study developed an image analysis method applying deep learning distinguish other round that deformed on substrate, based their morphological characteristics transmission electron microscopy images. This detected 4567 with mostly <10 h downwind emissions measured compositions, abundance, sizes, mixing states. number fraction, mass concentration all 10 % ± 1 %, 2 10.1 4.6 µg m-3, respectively. As samples aged emission up 5 h, TB fractions roughly increased 15 indicating processed primary particles. In more samples, fraction decreased possibly due dilution removal. We also showed within pyrocumulonimbus (PyroCb) activity various reveals abundances physical chemical properties wide range biomass-burning events enhances knowledge emissions, contributes evaluation impact TBs.

Язык: Английский

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Research Trends in Wildland Fire Prediction Amidst Climate Change: A Comprehensive Bibliometric Analysis

Forests, Год журнала: 2024, Номер 15(7), С. 1197 - 1197

Опубликована: Июль 10, 2024

Wildfire prediction plays a vital role in the management and conservation of forest ecosystems. By providing detailed risk assessments, it contributes to reduction fire frequency severity, safeguards resources, supports ecological stability, ensures human safety. This study systematically reviews wildfire literature from 2003 2023, emphasizing research trends collaborative trends. Our findings reveal significant increase activity between 2019 primarily driven by United States Forest Service Chinese Academy Sciences. The majority this was published prominent journals such as International Journal Wildland Fire, Ecology Management, Remote Sensing, Forests. These publications predominantly originate Europe, States, China. Since 2020, there has been substantial growth application machine learning techniques predicting fires, particularly estimating occurrence probabilities, simulating spread, projecting post-fire environmental impacts. Advanced algorithms, including deep ensemble learning, have shown superior accuracy, suggesting promising directions for future research. Additionally, integration with cellular automata markedly improved simulation behavior, enhancing both efficiency precision. profound impact climate change on also necessitates inclusion extensive data predictive models. Beyond conventional studies focusing behavior forecasting consequences fires become integral formulating more effective strategies. concludes that regional disparities knowledge exist, underscoring need capabilities underrepresented areas. Moreover, is an urgent requirement enhance artificial intelligence intensify efforts identifying leveraging various drivers refine accuracy. insights generated field will profoundly augment our understanding prediction, assisting policymakers practitioners managing resources sustainably averting calamities.

Язык: Английский

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Measurements of Total Aerosol Concentration in the Stratosphere: A New Balloon‐Borne Instrument and a Report on the Existing Measurement Record

Journal of Geophysical Research Atmospheres, Год журнала: 2024, Номер 129(14)

Опубликована: Июль 12, 2024

Abstract The Stratospheric Total Aerosol Counter (STAC) is a lightweight balloon‐borne instrument that utilizes condensational growth techniques to measure the total aerosol concentration. STAC miniaturized version of legacy Wyoming condensation particle counter operated from 1974 through 2020 in middle latitudes and polar regions, with few measurements tropics. Here we provide description measurement record, demonstrating typical profiles exhibit peak number mixing ratio, values between 800 2,000 particles per mg air (mg −1 ), just below lapse rate tropopause (LRT). In tropics latitudes, ratios decrease above LRT likely due coagulation scavenging results transfer mass fewer but larger Junge layer. Exceptions this occur spring time where new layer 20 25 km frequently observed. poles, two distinct features: formation austral spring, an increasing ratio 17 presence meteoric smoke has been concentrated within vortex. High observed stratospheric ratios, excess , are at top profiles.

Язык: Английский

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Occurrence, abundance, and formation of atmospheric tarballs from a wide range of wildfires in the western US

Atmospheric chemistry and physics, Год журнала: 2024, Номер 24(19), С. 10985 - 11004

Опубликована: Окт. 1, 2024

Abstract. Biomass burning emits large numbers of organic aerosol particles, a subset which are called tarballs (TBs). TBs possess spherical morphology and unique physical, chemical, optical properties. They recognized as brown-carbon influencing the climate through absorption solar radiation. Aerosol particles were collected from wildfire agricultural-fire smoke sampled by NASA's DC-8 aircraft during Fire Influence on Regional to Global Environments Air Quality (FIREX-AQ) campaign in western US July September 2019. This study developed an image analysis method using deep learning distinguish other round that deformed substrate, based particles' morphological characteristics transmission electron microscopy images. detected 4567 TBs, with most occurring < 10 h downwind emissions, measured their compositions, abundance, sizes, mixing states. The number fraction, mass concentration corresponded ± 1 %, 2 10.1 4.6 µg m−3, respectively. As aged for up 5 after emission, TB fractions roughly increased % 15 indicating processed primary particles. We also observed associated pyrocumulonimbus (pyroCb) activity various reveals well physical chemical properties, wide range biomass-burning events enhances our knowledge contributing evaluation impact TBs.

Язык: Английский

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Airborne Observations Constrain Heterogeneous Nitrogen and Halogen Chemistry on Tropospheric and Stratospheric Biomass Burning Aerosol

Geophysical Research Letters, Год журнала: 2024, Номер 51(4)

Опубликована: Фев. 12, 2024

Abstract Heterogeneous chemical cycles of pyrogenic nitrogen and halides influence tropospheric ozone affect the stratosphere during extreme Pyrocumulonimbus (PyroCB) events. We report field‐derived N 2 O 5 uptake coefficients, γ (N ), ClNO yields, φ (ClNO from two aircraft campaigns observing fresh smoke in lower mid troposphere processed/aged upper (UTLS). Derived ) varied across full 0–1 range but was typically <0.5 smallest a PyroCB (<0.05). low agricultural (0.2–3.6 × 10 −3 extremely mid‐tropospheric wildfire (0.1 larger processed (0.7–5.0 ). Aged biomass burning aerosol UTLS had higher 17 that increased with sulfate liquid water, 1–2 orders magnitude than values for aqueous sulfuric used stratospheric models.

Язык: Английский

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