scholarly journals Regional radiative impact of volcanic aerosol from the 2009 eruption of Mt. Redoubt

2012 ◽  
Vol 12 (8) ◽  
pp. 3699-3715 ◽  
Author(s):  
C. L. Young ◽  
I. N. Sokolik ◽  
J. Dufek
Keyword(s):  
Radiative Transfer ◽  
Environmental Conditions ◽  
Radiative Forcing ◽  
The Arctic ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Aerosol Layer ◽  
Volcanic Aerosol ◽  
High Northern Latitude ◽  
Arctic Environment

Abstract. High northern latitude eruptions have the potential to release volcanic aerosol into the Arctic environment, perturbing the Arctic's climate system. We present assessments of shortwave (SW), longwave (LW) and net direct aerosol radiative forcing efficiencies and atmospheric heating/cooling rates caused by volcanic aerosol from the 2009 eruption of Mt. Redoubt by performing radiative transfer modeling constrained by NASA A-Train satellite data. The optical properties of volcanic aerosol were calculated by introducing a compositionally resolved microphysical model developed for both ash and sulfates. Two compositions of volcanic aerosol were considered in order to examine a fresh, ash rich plume and an older, ash poor plume. Optical models were incorporated into a modified version of the SBDART radiative transfer model. Our results indicate that environmental conditions, such as surface albedo and solar zenith angle (SZA), can influence the sign and the magnitude of the radiative forcing at the top of the atmosphere (TOA) and at the surface and the magnitude of the forcing in the aerosol layer. We find that a fresh, thin plume (~2.5–7 km) at an AOD (550 nm) range of 0.18–0.58 and SZA = 55° over snow cools the surface and warms the TOA, but the opposite effect is seen for TOA by the same layer over ocean. The layer over snow also warms by 64 W m−2AOD−1 more than the same plume over seawater. The layer over snow at SZA = 75° warms the TOA 96 W m−2AOD−1 less than it would at SZA = 55° over snow, and there is instead warming at the surface. We also find that plume aging can alter the magnitude of the radiative forcing. An aged plume over snow at SZA = 55° would warm the TOA and layer by 146 and 143 W m−2AOD−1 less than the fresh plume, while the aging plume cools the surface 3 W m−2AOD−1 more. Comparing results for the thin plume to those for a thick plume (~3–20 km), we find that the fresh, thick plume with AOD(550 nm) = 3, over seawater, and SZA = 55° heats the upper part of the plume in the SW ~28 K day−1 more and cools in the LW by ~6.3 K day−1 more than a fresh, thin plume under the same environmental conditions. We compare our assessments with those reported for other aerosols typical to the Arctic environment (smoke from wildfires, Arctic haze, and dust) to demonstrate the importance of volcanic aerosols.

scholarly journals Regional radiative impact of volcanic aerosol from the 2009 eruption of Redoubt volcano

2011 ◽  
Vol 11 (9) ◽  
pp. 26691-26740 ◽  
Author(s):  
C. L. Young ◽  
I. N. Sokolik ◽  
J. Dufek
Keyword(s):  
Radiative Transfer ◽  
Environmental Conditions ◽  
Radiative Forcing ◽  
The Arctic ◽  
Aerosol Layer ◽  
Volcanic Aerosol ◽  
Ozone Monitoring Instrument ◽  
High Northern Latitude ◽  
Arctic Environment ◽  
Nm Range

Abstract. High northern latitude eruptions have the potential to release volcanic aerosol into the Arctic environment, perturbing the Arctic's climate system. In this study, we present assessments of shortwave (SW), longwave (LW) and net direct aerosol radiative forcings (DARFs) and atmospheric heating/cooling rates caused by volcanic aerosol from the 2009 eruption of Redoubt Volcano by performing radiative transfer modeling constrained by NASA A-Train satellite data. The Ozone Monitoring Instrument (OMI), the Moderate Resolution Imaging Spectroradiometer (MODIS), and the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model for volcanic ash were used to characterize aerosol across the region. A representative range of aerosol optical depths (AODs) at 550 nm were obtained from MODIS, and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) was used to determine the altitude and thickness of the plumes. The optical properties of volcanic aerosol were calculated using a compositionally resolved microphysical model developed for both ash and sulfates. Two compositions of volcanic aerosol were considered in order to examine a fresh, ash rich plume and an older, ash poor plume. Optical models were incorporated into a modified version of the Santa Barbara Disort Atmospheric Radiative Transfer (SBDART) model. Radiative transfer calculations were made for a range of surface albedos and solar zenith angles (SZA) representative of the region. We find that the total DARF caused by a fresh, thin plume (~2.5–7 km) at an AOD (550 nm) range of 0.16–0.58 and SZA = 55° is –46 W m−2AOD−1 at the top of the atmosphere (TOA), 110 W m−2AOD−1 in the aerosol layer, and – 150 W m−2AOD−1 at the surface over seawater. However, the total DARF for the same plume over snow and at the same SZA at TOA, in the layer, and at the surface is 170, 170, and −2 W m−2AOD−1, respectively. We also see that the total DARF when SZA = 75° for the same layer over snow is 35 W m−2AOD−1 at TOA, 64 W m−2AOD−1 in the layer, and 11 W m−2AOD−1 at the surface. These results indicate that environmental conditions, such as surface albedo and SZA, control the sign of the radiative forcing at TOA and at the surface and the magnitude of the forcing in the aerosol layer. An older plume over snow at SZA = 55° would have total DARFs of 25, 31, and −5 W m−2AOD−1 at TOA, in the layer, and at the surface, respectively. Our results demonstrate that plume aging can alter the magnitude of the radiative forcing. We also compare results for the thin plume to those for a thick plume (~3–20 km) with an AOD (550 nm) range of 1 to 3. The fresh, thin plume with AOD = 0.58, over seawater, and SZA = 55° will heat the atmosphere in the SW by ~2.5 K day−1 and cool the atmosphere in the LW by ~0.3 Kday−1. The fresh, thick plume with AOD = 3 under the same environmental conditions will produce SW heating in the atmosphere by ~31 Kday−1 and atmospheric LW cooling of ~6.7 K day−1. These calculations convey the importance of vertical plume structure in determining the magnitudes of the radiative effects. We compare our assessments with those reported for other aerosols typical to the Arctic environment (smoke from wildfires, Arctic haze, and dust) to demonstrate the importance of volcanic aerosols.

Radiative forcing over the Arctic of aerosols from the August 2017 Canadian and Greenlandic wildfires

2021 ◽  
Author(s):  
Filippo Calì Quaglia ◽  
Daniela Meloni ◽  
Alcide Giorgio di Sarra ◽  
Tatiana Di Iorio ◽  
Virginia Ciardini ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Radiative Forcing ◽  
Solar Zenith Angle ◽  
Surface Albedo ◽  
High Arctic ◽  
The Arctic ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Aerosol Layer ◽  
Radiative Effect

<p>Extended and intense wildfires occurred in Northern Canada and, unexpectedly, on the Greenlandic West coast during summer 2017. The thick smoke plume emitted into the atmosphere was transported to the high Arctic, producing one of the largest impacts ever observed in the region. Evidence of Canadian and Greenlandic wildfires was recorded at the Thule High Arctic Atmospheric Observatory (THAAO, 76.5°N, 68.8°W, www.thuleatmos-it.it) by a suite of instruments managed by ENEA, INGV, Univ. of Florence, and NCAR. Ground-based observations of the radiation budget have allowed quantification of the surface radiative forcing at THAAO. </p><p>Excess biomass burning chemical tracers such as CO, HCN, H2CO, C2H6, and NH3 were  measured in the air column above Thule starting from August 19 until August 23. The aerosol optical depth (AOD) reached a peak value of about 0.9 on August 21, while an enhancement of wildfire compounds was  detected in PM10. The measured shortwave radiative forcing was -36.7 W/m2 at 78° solar zenith angle (SZA) for AOD=0.626.</p><p>MODTRAN6.0 radiative transfer model (Berk et al., 2014) was used to estimate the aerosol radiative effect and the heating rate profiles at 78° SZA. Measured temperature profiles, integrated water vapour, surface albedo, spectral AOD and aerosol extinction profiles from CALIOP onboard CALIPSO were used as model input. The peak  aerosol heating rate (+0.5 K/day) was  reached within the aerosol layer between 8 and 12 km, while the maximum radiative effect (-45.4 W/m2) is found at 3 km, below the largest aerosol layer.</p><p>The regional impact of the event that occurred on August 21 was investigated using a combination of atmospheric radiative transfer modelling with measurements of AOD and ground surface albedo from MODIS. The aerosol properties used in the radiative transfer model were constrained by in situ measurements from THAAO. Albedo data over the ocean have been obtained from Jin et al. (2004). Backward trajectories produced through HYSPLIT simulations (Stein et al., 2015) were also employed to trace biomass burning plumes.</p><p>The radiative forcing efficiency (RFE) over land and ocean was derived, finding values spanning from -3 W/m2 to -132 W/m2, depending on surface albedo and solar zenith angle. The fire plume covered a vast portion of the Arctic, with large values of the daily shortwave RF (< -50 W/m2) lasting for a few days. This large amount of aerosol is expected to influence cloud properties in the Arctic, producing significant indirect radiative effects.</p>

scholarly journals A simple model for cloud radiative forcing

2009 ◽  
Vol 9 (2) ◽  
pp. 8541-8560 ◽  
Author(s):  
T. Corti ◽  
T. Peter
Keyword(s):  
Energy Balance ◽  
Simple Model ◽  
Radiative Transfer ◽  
Environmental Conditions ◽  
Radiative Forcing ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Cloud Radiative Forcing ◽  
Model Equations ◽  
Better Than

Abstract. We present a simple model for the longwave and shortwave cloud radiative forcing based on the evaluation of extensive radiative transfer calculations. The simplicity of the model equations fosters the understanding on how clouds affect the Earth's energy balance. In comparison with results from a comprehensive radiative transfer model, the accuracy of our parameterization is typically better than 20%. We demonstrate the usefulness of our model using the example of tropical cirrus clouds. We conclude that possible applications for the model include the fast estimate of cloud radiative forcing, the evaluation of the sensitivity to changes in environmental conditions, and as a tool in education.

scholarly journals Assessment of Aerosol Radiative Forcing with 1-D Radiative Transfer Modeling in the U. S. South-East

Atmosphere ◽  
2018 ◽  
Vol 9 (7) ◽  
pp. 271 ◽  
Author(s):  
Erica Alston ◽  
Irina Sokolik
Keyword(s):  
Radiative Transfer ◽  
Radiative Forcing ◽  
Global Climate Model ◽  
Regional Scale ◽  
Climate Impacts ◽  
Radiative Properties ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Aerosol Layer ◽  
Potential Implication

Aerosols and their radiative properties play an integral part in understanding Earth’s climate. It is becoming increasingly common to examine aerosol’s radiative impacts on a regional scale. The primary goal of this research is to explore the impacts of regional aerosol’s forcing at the surface and top-of-atmosphere (TOA) in the south-eastern U.S. by using a 1-D radiative transfer model. By using test cases that are representative of conditions common to this region, an estimate of aerosol forcing can be compared to other results. Speciation data and aerosol layer analysis provide the basis for the modeling. Results indicate that the region experiences TOA cooling year-round, where the winter has TOA forcings between −2.8 and −5 W/m2, and the summer has forcings between −5 and −15 W/m2 for typical atmospheric conditions. Surface level forcing efficiencies are greater than those estimated for the TOA for all cases considered i.e., urban and non-urban background conditions. One potential implication of this research is that regional aerosol mixtures have effects that are not well captured in global climate model estimates, which has implications for a warming climate where all radiative inputs are not well characterized, thus increasing the ambiguity in determining regional climate impacts.

Greenhouse effects of aircraft emissions as calculated by a radiative transfer model

1995 ◽  
Vol 13 (4) ◽  
pp. 413-418 ◽  
Author(s):  
J. P. F. Fortuin ◽  
R. van Dorland ◽  
W. M. F. Wauben ◽  
H. Kelder
Keyword(s):  
Water Vapor ◽  
Radiative Transfer ◽  
Indirect Effect ◽  
Radiative Forcing ◽  
Combustion Products ◽  
Ozone Production ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Aircraft Emissions ◽  
The North

Abstract. With a radiative transfer model, assessments are made of the radiative forcing in northern mid-latitudes due to aircraft emissions up to 1990. Considered are the direct climate effects from the major combustion products carbon dioxide, nitrogen dioxide, water vapor and sulphur dioxide, as well as the indirect effect of ozone production from NOx emissions. Our study indicates a local radiative forcing at the tropopause which should be negative in summer (–0.5 to 0.0 W/m2) and either negative or positive in winter (–0.3 to 0.2 W/m2). To these values the indirect effect of contrails has to be added, which for the North Atlantic Flight Corridor covers the range –0.2 to 0.3 W/m2 in summer and 0.0 to 0.3 W/m2 in winter. Apart from optically dense non-aged contrails during summer, negative forcings are due to solar screening by sulphate aerosols. The major positive contributions come from contrails, stratospheric water vapor in winter and ozone in summer. The direct effect of NO2 is negligible and the contribution of CO2 is relatively small.

scholarly journals Accounting for the effect of horizontal gradients in limb measurements of scattered sunlight

2007 ◽  
Vol 7 (6) ◽  
pp. 16155-16183 ◽  
Author(s):  
J. Puķīte ◽  
S. Kühl ◽  
T. Deutschmann ◽  
U. Platt ◽  
T. Wagner
Keyword(s):  
Monte Carlo ◽  
Radiative Transfer ◽  
Scattered Light ◽  
Trace Gases ◽  
The Arctic ◽  
Radiative Transfer Model ◽  
Boreal Winter ◽  
Transfer Model ◽  
Measurement Sensitivity ◽  
Horizontal Gradients

Abstract. Limb measurements provided by the SCanning Imaging Absorption spectrometer for Atmospheric CHartographY (SCIAMACHY) on the ENVISAT satellite allow retrieving stratospheric profiles of various trace gases on a global scale, among them BrO for the first time. For limb observations in the UV/VIS spectral region the instrument measures scattered light with a complex distribution of light paths: the light is measured at different elevation angles and can be scattered or absorbed in the atmosphere or reflected by the ground. By means of spectroscopy and radiative transfer modelling the measurements can be inverted to retrieve the vertical distribution of stratospheric trace gases. A full spherical 3-D Monte Carlo radiative transfer model "Tracy-II" is applied in this study. The Monte Carlo method benefits from conceptual simplicity and allows realizing the concept of full spherical geometry of the atmosphere and also its 3-D properties, which is important for a realistic description of the limb geometry. Furthermore it allows accounting for horizontal gradients in the distribution of trace gases. In this study the effect ofhorizontal inhomogeneous distributions of trace gases on the retrieval of profiles from limb measurements of scattered UV/VIS light is investigated. We introduce a method to correct for this effect by combining consecutive limb scanning sequences and utilizing the overlap in their measurement sensitivity regions. It is found that if horizontal inhomogenity is not properly accounted for, typical errors of 20% for NO2 and up to 50% for OClO around the altitude of the profile peak can arise for measurements close to the Arctic polar vortex boundary in boreal winter.

scholarly journals Improved estimate of global dust radiative forcing using a coupled chemical transport-radiative transfer model

2013 ◽  
Vol 13 (1) ◽  
pp. 2415-2456 ◽  
Author(s):  
L. Zhang ◽  
Q. B. Li ◽  
Y. Gu ◽  
K. N. Liou ◽  
B. Meland
Keyword(s):  
Radiative Transfer ◽  
Vertical Profile ◽  
Radiative Forcing ◽  
Chemical Transport ◽  
Dust Particles ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Vertical Profiles ◽  
Dust Source ◽  
Source Regions

Abstract. Atmospheric mineral dust particles exert significant direct radiative forcings and are critical drivers of climate change. Here, we use the GEOS-Chem global three-dimensional chemical transport model (3-D CTM) coupled online with the Fu-Liou-Gu (FLG) radiative transfer model (RTM) to investigate the dust radiative forcing and heating rates based on different dust vertical profiles. The coupled calculations using a realistic dust vertical profile simulated by GEOS-Chem minimize the physical inconsistencies between 3-D CTM aerosol fields and the RTM. The use of GEOS-Chem simulated aerosol optical depth (AOD) vertical profiles as opposed to the FLG prescribed AOD vertical profiles leads to greater and more spatially heterogeneous changes in estimated radiative forcing and heating rate produced by dust. Both changes can be attributed to a different vertical structure between dust and non-dust source regions. Values of the dust AOD are much larger in the middle troposphere, though smaller at the surface when the GEOS-Chem simulated AOD vertical profile is used, which leads to a much stronger heating rate in the middle troposphere. Compared to FLG vertical profile, the use of GEOS-Chem vertical profile reduces the solar radiative forcing effect by about 0.2–0.25 W m−2 and the Infrared (IR) radiative forcing over the African and Asia dust source regions by about 0.1–0.2 W m−2. Differences in the solar radiative forcing at the surface between using the GEOS-Chem vertical profile and the FLG vertical profile are most significant over the Gobi desert with a value of about 1.1 W m−2. The radiative forcing effect of dust particles is more pronounced at the surface over the Sahara and Gobi deserts by using FLG vertical profile, while it is less significant over the downwind area of Eastern Asia.

Process-Based Decomposition of the Decadal Climate Difference between 2002–13 and 1984–95

2017 ◽  
Vol 30 (12) ◽  
pp. 4373-4393 ◽  
Author(s):  
Xiaoming Hu ◽  
Yana Li ◽  
Song Yang ◽  
Yi Deng ◽  
Ming Cai
Keyword(s):  
Radiative Transfer ◽  
Heat Storage ◽  
Decomposition Analysis ◽  
Arctic Region ◽  
The Arctic ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Model Calculations ◽  
Surface Warming ◽  
Decadal Climate

This study examines at the process level the climate difference between 2002–13 and 1984–95 in ERA-Interim. A linearized radiative transfer model is used to calculate the temperature change such that its thermal radiative cooling would balance the energy flux perturbation associated with the change of an individual process, without regard to what causes the change of the process in the first place. The global mean error of the offline radiative transfer model calculations is 0.09 K, which corresponds to the upper limit of the uncertainties from a single term in the decomposition analysis. The process-based decomposition indicates that the direct effect of the increase of CO2 (0.15 K) is the largest contributor to the global warming between the two periods (about 0.27 K). The second and third largest contributors are the cloud feedback (0.14 K) and the combined effect of the oceanic heat storage and evaporation terms (0.11 K), respectively. The largest warming associated with the oceanic heat storage term is found in the tropical Pacific and Indian Oceans, with relatively weaker warming over the tropical Atlantic Ocean. The increase in atmospheric moisture adds another 0.1 K to the global surface warming, but the enhancement in tropical convections acts to reduce the surface warming by 0.17 K. The ice-albedo and atmospheric dynamical feedbacks are the two leading factors responsible for the Arctic polar warming amplification (PWA). The increase of atmospheric water vapor over the Arctic region also contributes substantially to the Arctic PWA pattern.

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