Comment on egusphere-2023-995 DOI Creative Commons
L. W. Thomason, Travis N. Knepp

Опубликована: Май 30, 2023

Abstract. Using a common analysis approach for data sets produced by the Stratospheric Aerosol and Gas Experiment instruments SAGE II III/ISS, we identify 13 likely smoke events based on enhancements in aerosol extinction coefficient. Nine of these are sufficiently large compared to ambient levels compute mean mid-latitude 1020-nm optical depth that range from 0.0005 0.011. We also note that, events, 525 1020 nm coefficient ratio asymptotes at high values between 2 3 suggesting is relatively small (<0.3 μm) consistent event event. Most primarily confined lower stratosphere rarely can be observed above 20 km. infer an increase frequency (1984–1991, 1996–2005) III/ISS (2017–present) periods almost factor two largest occur latter set. However, given low frequencies overall, not confident differences attributed changes periods. attempt disentangle mixing northern hemisphere summer 1991 pyrocumulus (Baie-Comeau, Quebec) Mt. Pinatubo conclude while there evidence stratosphere, virtually all enhanced observations mid-latitudes associated with eruption.

Язык: Английский

The Dynamics of Megafire Smoke Plumes in Climate Models: Why a Converged Solution Matters for Physical Interpretations DOI Creative Commons
Stephen R. Guimond, Jon Reisner, M. K. Dubey

и другие.

Journal of Advances in Modeling Earth Systems, Год журнала: 2023, Номер 15(4)

Опубликована: Апрель 1, 2023

Abstract As the climate system warms, megafires have become more frequent with devastating effects. A byproduct of these events is creation smoke plumes that can rise into stratosphere and spread across globe where they reside for many months. To gain a deeper understanding plume dynamics, global simulations megafire were performed at wide range grid spacings from 2.0° down to 7 km, including km nonhydrostatic experiment. The analysis focuses on how resolved dynamics affects specification characteristics such as injection height black carbon (BC) mass. Prior studies initialize one or few points this shown here produce severely dissipative dynamics. In order validate observations, enhancements offset dissipation necessary. Using numerically converged simulation, sensitivity tests show approximate observed stratospheric lifetime, reduction in BC fraction by 50% necessary external mixtures. vorticity also analyzed Lagrangian budget understand mechanisms responsible evolution collocated anticyclonic vortex. results be distilled simple conceptual model. rises, air diverges top updraft largest concentrations are found. This divergence induces dilution background cyclonic absolute producing an Vortex decay occurs opposite arguments.

Язык: Английский

Процитировано

4
Light absorption enhancement of black carbon in a pyrocumulonimbus cloud DOI Creative Commons
Payton Beeler, Joshin Kumar, Joshua P. Schwarz

и другие.

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Июль 25, 2024

Abstract Pyrocumulonimbus (pyroCb) firestorm systems have been shown to inject significant amounts of black carbon (BC) the stratosphere with a residence time several months. Injected BC warms local stratospheric air, consequently perturbing transport and hence spatial distributions ozone water vapor. A distinguishing feature BC-containing particles residing within pyroCb smoke is their thick surface coatings made condensed organic matter. When coated non-refractory materials, BC’s absorption enhanced, yet enhancement factor ( E abs ) for not well constrained. Here, we perform particle-scale measurements mass, morphology, coating thickness from inside cloud quantify using an established particle-resolved optics model. We find that population-averaged asymptotes 2.0 increasing thickness. This value denotes upper limit thickly in atmosphere. Our results provide observationally constrained parameterizations improved radiative transfer calculations events.

Язык: Английский

Процитировано

1
Enhancing Global Simulation of Smoke Injection Height for Intense Pyro‐Convection Through Coupling an Improved One‐Dimensional Plume Rise Model in CAM‐chem DOI Creative Commons
Chaoqun Ma, Ruijing Ni, Hang Su

и другие.

Journal of Advances in Modeling Earth Systems, Год журнала: 2024, Номер 16(10)

Опубликована: Окт. 1, 2024

Abstract The impact of wildfire smoke is largely determined by the height where they are injected into atmosphere. Current plume rise models tend to underestimate high injection heights because previous and configurations were mainly constrained validated observation from Multi‐angle Imaging SpectroRadiometer (MISR), which most cases inject low within planetary boundary layer (PBL). Here we retrieve intense pyro‐convections based on pyrocumulonimbus satellite images in PYROCAST data set alongside meteorological reanalysis. It augments MISR with up upper troposphere lower stratosphere (UTLS). Constrained both PYROCAST, show that a scaling down factor 0.2 entrainment efficiency parameterized one‐dimensional plume‐rise model (1‐D PRM, Freitas et al. (2010, https://doi.org/10.5194/acp‐10‐585‐2010 )) significantly improves performance for without compromising accuracy cases. We also found fire intensity input can be obtained through simplified dependence biome biomass burning emission flux. While being unable represent before, improved 1‐D PRM predicts similarly well near PBL UTLS. then coupled Community Atmosphere Model Chemistry (CAM‐chem). CAM‐chem‐PRM, when predicting tests imitating real BB emission, exhibited consistent predictive capabilities standalone while saw mere 15% increase computation time.

Язык: Английский

Процитировано

1
Quantifying SAGE II (1984–2005) and SAGE III/ISS (2017–2022) observations of smoke in the stratosphere DOI Creative Commons
L. W. Thomason, Travis N. Knepp

Atmospheric chemistry and physics, Год журнала: 2023, Номер 23(18), С. 10361 - 10381

Опубликована: Сен. 19, 2023

Abstract. Using a common analysis approach for data sets produced by the Stratospheric Aerosol and Gas Experiment instruments SAGE II III/ISS, we identify 13 likely smoke events based on enhancements in aerosol extinction coefficient. Nine of these are sufficiently large compared to ambient levels compute mean mid-latitude 1020 nm optical depth that range from 0.0005 0.011. We also note that, events, 525 coefficient ratio asymptotes at high values between 2 3, suggesting radius is relatively small (< 0.3 µm) consistent event event. Most primarily confined lower stratosphere rarely can be observed above 20 km. infer an increase frequency (1984–1991, 1996–2005) III/ISS (2017-present) periods almost factor two largest occur latter set. However, given low frequencies overall, not confident differences attributed changes periods. attempt disentangle mixing Northern Hemisphere summer 1991 pyrocumulus (Baie-Comeau, Quebec) Mt. Pinatubo conclude while there evidence stratosphere, virtually all enhanced observations northern mid-latitudes associated with eruption.

Язык: Английский

Процитировано

3
Insights into Pyrocumulus aerosol composition: black carbon content and organic vapor condensation DOI Creative Commons
Kyle Gorkowski, Eunmo Koo, Spencer Jordan

и другие.

Environmental Science Atmospheres, Год журнала: 2023, Номер 4(1), С. 80 - 87

Опубликована: Ноя. 29, 2023

Megafires are increasingly generating Pyrocumulus clouds (PyroCus) through the interplay of atmospheric conditions such as stability and humidity, hot updrafts, emitted aerosols from burning vegetation.

Язык: Английский

Процитировано

2
Reply on RC3 DOI Creative Commons
Travis N. Knepp

Опубликована: Янв. 26, 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 as well quantify uncertainty in estimates. This carried out by solving for both single bimodal lognormal distributions. The work presented herein falls under 2 general headings: 1. theoretical study determine accuracy of this methodology; 2. solution applied III/ISS records with brief case analysis 2022 Hunga Tonga eruption.

Язык: Английский

Процитировано

0
Reply on RC1 DOI Creative Commons
Travis N. Knepp

Опубликована: Янв. 26, 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 as well quantify uncertainty in estimates. This carried out by solving for both single bimodal lognormal distributions. The work presented herein falls under 2 general headings: 1. theoretical study determine accuracy of this methodology; 2. solution applied III/ISS records with brief case analysis 2022 Hunga Tonga eruption.

Язык: Английский

Процитировано

0
Reply on RC2 DOI Creative Commons
Travis N. Knepp

Опубликована: Янв. 26, 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 as well quantify uncertainty in estimates. This carried out by solving for both single bimodal lognormal distributions. The work presented herein falls under 2 general headings: 1. theoretical study determine accuracy of this methodology; 2. solution applied III/ISS records with brief case analysis 2022 Hunga Tonga eruption.

Язык: Английский

Процитировано

0
Comment on egusphere-2024-880 DOI Creative Commons
Kouji Adachi, Jack E. Dibb, Joseph M. Katich

и другие.

Опубликована: Июнь 16, 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

Процитировано

0
Comment on egusphere-2024-880 DOI Creative Commons
Kouji Adachi, Jack E. Dibb, Joseph M. Katich

и другие.

Опубликована: Июнь 20, 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

Процитировано

0