scholarly journals Background Stratospheric Aerosol Variations Deduced from Satellite Observations

2012 ◽  
Vol 51 (4) ◽  
pp. 799-812 ◽  
Author(s):  
Yu Liu ◽  
Xuepeng Zhao ◽  
Weiliang Li ◽  
Xiuji Zhou
Keyword(s):  
Lower Stratosphere ◽  
Particle Growth ◽  
Stratospheric Aerosol ◽  
Injection Rate ◽  
Large Uncertainty ◽  
Sulfur Dioxide Emissions ◽  
Aerosol Mass ◽  
Rate Of Increase ◽  
Aerosol Number Concentration ◽  
Aerosol Extinction Coefficient

AbstractThe Stratospheric Aerosol and Gas Experiment II (SAGE II) aerosol products from 1998 to 2004 have been analyzed for the tendency of changes in background stratospheric aerosol properties. The aerosol extinction coefficient E has apparently increased in the midlatitude lower stratosphere (LS) in both hemispheres, at an annual rate that is as great as 2%–5%. Positive changes in the aerosol surface area density S in the midlatitude LS are most distinct, with a rate of increase that is as high as 5%–6% annually. At the same time, there has been a secular decrease in aerosol effective radius R, especially in the tropical LS, at a rate of up to −2.5% yr−1. Corresponding to these trends, the aerosol number concentration is inferred to have increased by roughly 5%–10% yr−1 in the tropical LS and by 4%–8% yr−1 in the midlatitude LS. Changes in aerosol mass are also deduced, with rates of increase in the midlatitude LS that are in the range of 1%–5% yr−1. The large uncertainty in operational S product is the major factor influencing the trend in S, aerosol number concentrations, and mass. The authors’ global assessment supports the speculation of Hofmann et al. on the basis of local observations that the cause of an increase in lidar backscatter over a similar period was a consequence of aerosol particle growth due to enhanced anthropogenic sulfur dioxide emissions. Moreover, it is found that an increase in the injection rate of condensation nuclei from the troposphere to the stratosphere at tropical latitudes is required to sustain the increase in stratospheric aerosol concentrations identified in this analysis.

scholarly journals Organic Vapor Condensation in Pyro-cumulonimbus Outflow Explains Large Stratospheric Smoke Mass Injection and Thickly Coated Black Carbon

2021 ◽  
Author(s):  
Manvendra K. Dubey ◽  
Kyle Gorkowski ◽  
Jon Reisner ◽  
Katherine Benedict ◽  
Alex Josephson ◽  
...  
Keyword(s):  
Black Carbon ◽  
Lower Stratosphere ◽  
Climate Model ◽  
Stratospheric Aerosol ◽  
Vapor Condensation ◽  
Fuel Loading ◽  
Ice Clouds ◽  
Airborne Measurements ◽  
Aerosol Mass ◽  
Cloud Resolving Model

<p>Airborne measurements of upper troposphere and lower stratosphere biomass burning smoke show a large size mode at 350nm radius. Furthermore,  very thickly coated black carbon (300-400nm radius) is observed in 2 month aged Pyro-cumulonimbus (PyroCb) smoke in the lower stratosphere. Finally, the stratospheric aerosol mass injections from the 2017 British Columbia (BC17) PyroCbs are much larger than fuel loading predicts.  We propose a secondary organic aerosol (SOA) production mechanism where volatile organic compounds (VOCs) emitted by fires condense in the cold convective PyroCb updrafts to explain the aforementioned data. Observations supporting this mechanism present in FIREX-AQ, ATOM and CARIBEC airborne data are synthesized. The condensation, evaporation and coagulation mechanisms are implemented into LANL’s large eddy cloud resolving model called HIGRAD.  Our simulations provide insights into the vertical distribution of SOA in the BC17 PyroCb and the role of warm and ice clouds in lofting it into the lower stratosphere. We show that SOA formation can increase aerosols by a factor of 2-3 and latent heat from warm and ice clouds adds 5 km to the injection height of BC17 fire smoke. The fate, transport and impacts  of smoke from BC17 and 2020 Australian fires are examined using climate model (CESM) simulations.  </p>

Detection of an enhanced stratospheric aerosol layer above Europe one year after the eruption of the volcano Raikoke

2021 ◽  
Author(s):  
Laura Tomsche ◽  
Andreas Marsing ◽  
Tina Jurkat-Witschas ◽  
Johannes Lucke ◽  
Katharina Kaiser ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Lower Stratosphere ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Sulfate Aerosol ◽  
Aerosol Layer ◽  
Volcanic Aerosol ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass

<p>Extreme volcanic eruptions inject significant amounts of sulfur-containing species into the lower stratosphere and sustain the stratospheric aerosol layer which tends to cool the atmosphere and surface temperatures.</p><p>During the BLUESKY campaign in May/June 2020, the aerosol composition and its precursor gas SO2 were measured with a time-of-flight aerosol mass spectrometer onboard the research aircraft HALO and with a atmospheric chemical ionization mass spectrometer onboard the DLR Falcon. While SO2 was slightly above background levels in the lower stratosphere above Europe, the aerosol mass spectrometer detected an extended aerosol layer. This sulfate aerosol layer was observed on most of the HALO flights and the sulfate mixing ratio increased significantly between 10 and 14 km altitude. Back trajectory calculations show no recent transport of polluted boundary layer air or ground-based emissions into the lower stratosphere. Therefore, we suggest that the stratospheric sulfate aerosol layer might be attributed to the aged stratospheric plume of the volcano Raikoke in Japan. In June 2019, Raikoke injected huge amounts of SO2 into the lower stratosphere, which were converted to sulfate and contributed to the stratospheric aerosol layer. This decaying volcanic aerosol layer was observed with the aerosol mass spectrometer over Europe a year after the eruption. The long-term volcanic remnants enhance the total stratospheric aerosol surface area, facilitate heterogeneous reactions on these particles and provide additional cloud condensation nuclei in the UTLS. They further offset some of the reduced sulfur burden from aviation that was observed during the COVID-19 lockdown in 2020. <br>The sensitive and highly time resolved airborne measurements of composition and size of stratospheric aerosol from an explosive volcanic eruption help to better constrain sulfur chemistry in the lower stratosphere, validate satellite observations near their detection threshold and can be used to evaluate dispersion and chemistry-climate models on long-term effects of volcanic aerosol. </p>

scholarly journals Gravity-wave effects on tracer gases and stratospheric aerosol concentrations during the 2013 ChArMEx campaign

2016 ◽  
Author(s):  
Fabrice Chane Ming ◽  
Damien Vignelles ◽  
Fabrice Jegou ◽  
Gwenael Berthet ◽  
Jean-Batiste Renard ◽  
...  
Keyword(s):  
Gravity Wave ◽  
Lower Stratosphere ◽  
Weather Forecasting ◽  
Stratospheric Aerosol ◽  
Thin Layers ◽  
Vertical Wind ◽  
Specific Humidity ◽  
Small Scale ◽  
Strong Activity ◽  
Dynamical Parameters

Abstract. Coupled balloon-borne observations of Light Optical Aerosol Counter (LOAC), M10 meteorological global positioning system (GPS) sondes, ozonesondes and GPS radio occultation data, are examined to identify gravity-wave (GW) induced fluctuations on tracer gases and on the vertical distribution of stratospheric aerosol concentrations during the 2013 ChArMEx (Chemistry-Aerosol Mediterranean Experiment) campaign. Observations reveal signatures of GWs with short vertical wavelengths less than 4 km in dynamical parameters and tracer constituents which are also correlated with the presence of thin layers of strong local enhancements of aerosol concentrations in the upper troposphere and the lower stratosphere. In particular, this is evident from a case study above Ile du Levant (43.02 °N, 6.46 °E) on 26–29 July 2013. Observations show a strong activity of dominant mesoscale inertia GWs with horizontal and vertical wavelengths of 370–510 km and 2–3 km respectively, and periods of 10–13 h propagating southward at altitudes of 13–20 km and eastward above 20 km during 27–28 July which is also captured by the European Center for Medium range Weather Forecasting (ECMWF) analyses. Ray-tracing experiments indicate the jet-front system to be the source of observed GWs. Simulated vertical profiles of dynamical parameters with large stratospheric vertical wind maximum oscillations ± 40 mms−1 are produced for the dominant mesoscale GW using the simplified linear GW theory. Parcel advection method reveals signatures of GWs in the ozone mixing ratio and the specific humidity. Simulated vertical wind perturbations of the dominant GW and small-scale perturbations of aerosol concentration (aerosol size of 0.2–0.7 μm) are in phase in the lower stratosphere. Present results support the importance of vertical wind perturbations in the GW-aerosol relation. The observed mesoscale GW induces a strong modulation of the amplitude of tracer gases and the stratospheric aerosol background.

scholarly journals Chemistry-climate model simulations of the Mt. Pinatubo eruption using CCMI and CMIP6 stratospheric aerosol data

2017 ◽  
Author(s):  
Laura Revell ◽  
Andrea Stenke ◽  
Beiping Luo ◽  
Stefanie Kremser ◽  
Eugene Rozanov ◽  
...  
Keyword(s):  
Lower Stratosphere ◽  
Climate Model ◽  
Stratospheric Aerosol ◽  
Radiative Properties ◽  
Gap Filling ◽  
Data Set ◽  
Model Simulations ◽  
Ozone Loss ◽  
Pinatubo Eruption ◽  
Climate Model Simulations

Abstract. To simulate the impacts of volcanic eruptions on the stratosphere, chemistry-climate models that do not include an online aerosol module require temporally and spatially resolved aerosol size parameters for heterogeneous chemistry and aerosol radiative properties as a function of wavelength. For phase 1 of the Chemistry-Climate Model Initiative (CCMI-1) and, later, for phase 6 of the Coupled Model Intercomparison Project (CMIP6) two such stratospheric aerosol data sets were compiled, whose functional capability and representativeness are compared here. For CCMI-1, the SAGE-4λ data set was compiled, which hinges on the measurements at four wavelengths of the SAGE (Stratospheric Aerosol and Gas Experiment) II satellite instrument and uses ground-based Lidar measurements for gap-filling immediately after the Mt. Pinatubo eruption, when the stratosphere was optically opaque for SAGE II. For CMIP6, the new SAGE-3λ data set was compiled, which excludes the least reliable SAGE II wavelength and uses CLAES (Cryogenic Limb Array Etalon Spectrometer) measurements on UARS, the Upper Atmosphere Research Satellite, for gap-filling following the Mt. Pinatubo eruption instead of ground-based Lidars. Here, we performed SOCOLv3 (Solar Climate Ozone Links version 3) chemistry-climate model simulations of the recent past (1986–2005) to investigate the impact of the Mt. Pinatubo eruption in 1991 on stratospheric temperature and ozone and how this response differs depending on which aerosol data set is applied. The use of SAGE-4λ results in heating and ozone loss being overestimated in the lower stratosphere compared to observations in the post-eruption period by approximately 3 K and 0.2 ppmv, respectively. However, less heating occurs in the model simulations based on SAGE-3λ, because the improved gap-filling procedures after the eruption lead to less aerosol loading in the tropical lower stratosphere. As a result, simulated temperature anomalies in the model simulations based on SAGE-3λ for CMIP6 are in excellent agreement with MERRA and ERA-Interim reanalyses in the post-eruption period. Less heating in the simulations with SAGE-3λ means that the rate of tropical upwelling does not strengthen as much as it does in the simulations with SAGE-4λ, which limits dynamical uplift of ozone and therefore provides more time for ozone to accumulate in tropical mid-stratospheric air. Ozone loss following the Mt. Pinatubo eruption is overestimated by 0.1 ppmv in the model simulations based on SAGE-3λ, which is a better agreement with observations than in the simulations based on SAGE-4λ. Overall, the CMIP6 stratospheric aerosol data set, SAGE-3λ, allows SOCOLv3 to more accurately simulate the post-Pinatubo eruption period.

scholarly journals Evidence for the predictability of changes in the stratospheric aerosol size following volcanic eruptions of diverse magnitudes using space-based instruments

2020 ◽  
Author(s):  
Larry W. Thomason ◽  
Mahesh Kovilakam ◽  
Anja Schmidt ◽  
Christian von Savigny ◽  
Travis Knepp ◽  
...  
Keyword(s):  
Size Distribution ◽  
Extinction Coefficient ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Global Climate Models ◽  
Aerosol Size Distribution ◽  
Aerosol Layer ◽  
Aerosol Extinction ◽  
Volcanic Event ◽  
Aerosol Extinction Coefficient

Abstract. An analysis of multiwavelength stratospheric aerosol extinction coefficient data from the Stratospheric Aerosol and Gas Experiment II and III/ISS instruments is used to demonstrate a coherent relationship between the perturbation in extinction coefficient in an eruption's main aerosol layer and an apparent change in aerosol size distribution that spans multiple orders of magnitude in the stratospheric impact of a volcanic event. The relationship is measurement-based and does not rely on assumptions about the aerosol size distribution. We note limitations on this analysis including that the presence of significant amounts of ash in the main aerosol layer may significantly modulate these results. Despite this limitation, these findings represent a unique opportunity to verify the performance of interactive aerosol models used in Global Climate Models and Earth System Model and may suggest an avenue for improving aerosol extinction coefficient measurements from single channel observations such the Optical Spectrograph and Infrared Imager System as they rely on a priori assumptions about particle size.

scholarly journals An evaluation of the SAGE III Version 4 aerosol extinction coefficient and water vapor data products

2009 ◽  
Vol 9 (5) ◽  
pp. 22177-22222
Author(s):  
L. W. Thomason ◽  
J. R. Moore ◽  
M. C. Pitts ◽  
J. M. Zawodny ◽  
E.-W. Chiou
Keyword(s):  
Water Vapor ◽  
Extinction Coefficient ◽  
Stratospheric Aerosol ◽  
Data Sets ◽  
Aerosol Extinction ◽  
Data Products ◽  
Mean Differences ◽  
Aerosol Extinction Coefficient ◽  
Polar Ozone

Abstract. Herein, we provide an assessment of the data quality of Stratospheric Aerosol and Gas Experiment (SAGE III) Version 4 aerosol extinction coefficient and water vapor data products. The evaluation is based on comparisons with data from four instruments: SAGE II, the Polar Ozone and Aerosol Measurement (POAM III), the Halogen Occultation Experiment (HALOE), and the Microwave Limb Sounder (MLS). Since only about half of the SAGE III channels have a direct comparison with measurements by other instruments, we have employed some empirical techniques to evaluate measurements at some wavelengths. We find that the aerosol extinction coefficient measurements at 449, 520, 755, 869, and 1021 nm are reliable with accuracies and precisions on the order of 10% in the primary aerosol range of 15 to 25 km. We also believe this to be true of the aerosol measurements at 1545 nm though we cannot exclude some positive bias below 15 km. We recommend use of the 385 nm measurements above 16 km where the accuracy is on par with other aerosol channels. The 601 nm measurement is much noisier (~20%) than other channels and we suggest caution in the use of these data. We believe that the 676 nm data are clearly defective particularly above 20 km (accuracy as poor as 50%) and the precision is also low (~30%). We suggest excluding this channel under most circumstances. The SAGE III Version 4 water vapor data product appears to be high quality and is recommended for science applications in the stratosphere below 45 km. In this altitude range, the mean differences with all four corroborative data sets are no bigger than 15% and often less than 10% with exceptional agreement with POAM III and MLS. Above 45 km, it seems likely that SAGE III water vapor values are increasingly too large and should be used cautiously or avoided. We believe that SAGE III meets its preflight goal of 15% accuracy and 10% precision between 15 and 45 km. We do not currently recommend limiting the SAGE III water vapor data utility in the stratosphere by aerosol loading.

scholarly journals Evidence for the predictability of changes in the stratospheric aerosol size following volcanic eruptions of diverse magnitudes using space-based instruments

2021 ◽  
Vol 21 (2) ◽  
pp. 1143-1158 ◽  
Author(s):  
Larry W. Thomason ◽  
Mahesh Kovilakam ◽  
Anja Schmidt ◽  
Christian von Savigny ◽  
Travis Knepp ◽  
...  
Keyword(s):  
Extinction Coefficient ◽  
Climate Models ◽  
Single Channel ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Global Climate Models ◽  
Aerosol Size Distribution ◽  
Aerosol Layer ◽  
Aerosol Extinction ◽  
Aerosol Extinction Coefficient

Abstract. An analysis of multiwavelength stratospheric aerosol extinction coefficient data from the Stratospheric Aerosol and Gas Experiment II and III/ISS instruments is used to demonstrate a coherent relationship between the perturbation in extinction coefficient in an eruption's main aerosol layer and the wavelength dependence of that perturbation. This relationship spans multiple orders of magnitude in the aerosol extinction coefficient of stratospheric impact of volcanic events. The relationship is measurement-based and does not rely on assumptions about the aerosol size distribution. We note limitations on this analysis including that the presence of significant amounts of ash in the main sulfuric acid aerosol layer and other factors may significantly modulate these results. Despite these limitations, the findings suggest an avenue for improving aerosol extinction coefficient measurements from single-channel observations such as the Optical Spectrograph and Infrared Imager System as they rely on a prior assumptions about particle size. They may also represent a distinct avenue for the comparison of observations with interactive aerosol models used in global climate models and Earth system models.

scholarly journals Net terrestrial radiant flux in the vertical over Pune

MAUSAM ◽  
2022 ◽  
Vol 44 (2) ◽  
pp. 175-178
Author(s):  
K. JAYARAMAN ◽  
D.D. CHAKRABORTY ◽  
S.P. BHAGWAT
Keyword(s):  
Radiation Field ◽  
Lower Stratosphere ◽  
Radiant Flux ◽  
Rate Of Increase

The terrestrial radiant fluxes are being measured regularly at Pune using a balloon-borne radiometersonde. The net terrestrial radiant fluxes obtained from these measurements over a decade have been studied and results presented. The net terrestrial radiant flux increases with height and reaches a maximum around 12 km and then the rate of increase slows down near tropopause. In the lower stratosphere the fluxes again Increase before reaching a nearly steady value at around 25 km. The clouds and rainfall distributions seriously distort the radiation field.  

scholarly journals Spatial characteristics of aerosol physical properties over the northeastern parts of peninsular India

2005 ◽  
Vol 23 (10) ◽  
pp. 3219-3227 ◽  
Author(s):  
K. Niranjan ◽  
B. Melleswara Rao ◽  
P. S. Brahmanandam ◽  
B. L. Madhavan ◽  
V. Sreekanth ◽  
...  
Keyword(s):  
Physical Properties ◽  
Particle Growth ◽  
Back Trajectory ◽  
Peninsular India ◽  
Near Surface ◽  
Surface Mass ◽  
Accumulation Mode ◽  
Back Trajectory Analysis ◽  
Aerosol Mass ◽  
Northern Latitudes

Abstract. Measurements on aerosol spectral optical depths and near surface mass-size distributions made at several locations in the states of Andhra Pradesh, Orissa and Chattisgarh, constituting the northeastern part of the peninsular India during the ISRO-GBP land campaign-I show significant regional variations in aerosol physical properties. Higher spectral optical depths were observed in the coastal regions and over southern latitudes compared to interior continental regions and northern latitudes. The optical depths, size index "α" and the near surface aerosol mass concentrations indicate a relative abundance of nucleation mode aerosols in the northern latitudes, in contrast to the dominance of the accumulation mode aerosols at the eastern coastal and southern latitudes. The airmass pathways derived from the back trajectory analysis indicate that the higher aerosol population in the accumulation mode, and consequently the higher optical depths in the southern locations, could be due to the transport of aerosol from the polluted north Indian regions via the oceanic region over the Bay of Bengal, where significant particle growth is expected, increasing the population of accumulation mode aerosols over these regions.

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