Estimation of mineral dust direct radiative forcing at the European Aerosol Research Lidar NETwork site of Lecce, Italy, during the ChArMEx/ADRIMED summer 2013 campaign: Impact of radiative transfer model spectral resolutions

Abstract. Atmospheric aerosols play a crucial role in regional radiative budgets. Previous studies on clear-sky aerosol direct radiative forcing (ADRF) have mainly been limited to site-scale observations or model simulations for short-term cases, and long-term distributions of ADRF in China have not been portrayed yet. In this study, an accurate fine-resolution ADRF estimate at the surface was proposed. Multiplatform datasets, including satellite (MODIS aboard Terra and Aqua) and reanalysis datasets, served as inputs to the Santa Barbara Discrete Atmospheric Radiative Transfer (SBDART) model for ADRF simulation with consideration of the aerosol vertical profile over eastern China during 2000–2016. Specifically, single-scattering albedo (SSA) from the Modern-Era Retrospective Analysis for Research and Application, Version 2 (MERRA-2) was validated with sun photometers over eastern China. The gridded asymmetry parameter (ASY) was then simulated by matching the calculated top-of-atmosphere (TOA) radiative fluxes from the radiative transfer model with satellite observations (Clouds and the Earth's Radiant Energy System, CERES). The high correlation and small discrepancy (6–8 W m−2) between simulated and observed radiative fluxes at three sites (Baoshan, Fuzhou, and Yong'an) indicated that ADRF retrieval is feasible and has high accuracy over eastern China. Then this method was applied in each grid of eastern China, and the overall picture of ADRF distributions over eastern China during 2000–2016 was displayed. ADRF ranges from −220 to −20 W m−2, and annual mean ADRF is −100.21 W m−2, implying that aerosols have a strong cooling effect at the surface in eastern China. With the economic development and rapid urbanization, the spatiotemporal changes of ADRF during the past 17 years are mainly attributed to the changes of anthropogenic emissions in eastern China. Our method provides the long-term ADRF distribution over eastern China for the first time, highlighting the importance of aerosol radiative impact under climate change.

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Retrieval of Gridded Aerosol Direct Radiative Forcing Based on Multiplatform Datasets

10.5194/amt-2019-311 ◽

2019 ◽

Author(s):

Yanyu Wang ◽

Rui Lyu ◽

Xin Xie ◽

Meijin Huang ◽

Junshi Wu ◽

...

Keyword(s):

Radiative Transfer ◽

Radiative Forcing ◽

Radiant Energy ◽

Energy System ◽

East China ◽

Radiative Transfer Model ◽

Transfer Model ◽

Radiative Fluxes ◽

Direct Radiative Forcing

Abstract. Atmospheric aerosols play a crucial role in regional radiative budgets. Previous studies on clear-sky aerosol direct radiative forcing (ADRF) have mainly been limited to site-scale observations or model simulations for short-term cases, and long-term distributions of ADRF in China has not been portrayed yet. In this study, an accurate fine-resolution ADRF estimate at the surface was proposed. Multiplatform datasets, including satellite (Terra and Aqua) and reanalysis datasets, served as inputs to the Santa Barbara Discrete Atmospheric Radiative Transfer (SBDART) model for ADRF simulation with consideration of the aerosol vertical profile over East China during 2000–2016. Specifically, single scattering albedo (SSA) from the Modern-Era Retrospective Analysis for Research and Application, version 2 (MERRA-2) was validated with sunphotometers over East China. The gridded asymmetry parameter (ASY) was then simulated by matching the calculated top-of-atmosphere (TOA) radiative fluxes from the radiative transfer model with satellite observations (Clouds and the Earth's Radiant Energy System (CERES)). The high correlation and small discrepancy (6–8 W m-2) between simulated and observed radiative fluxes at three sites (Baoshan, Fuzhou, and Yong'an) indicated that ADRF retrieval is feasible and has high accuracy over East China. Then this method was applied in each grid of East China and the overall picture of ADRF distributions over East China during 2000–2016 was displayed. ADRF ranges from −220 to −20 W m-2, and annual mean ADRF is −100.21 W m-2, implying that aerosols have strong cooling effect at the surface during past 16 years. Finally, uncertainty analysis was also evaluated. Our method provides the long-term ADRF distribution over East China for the first time, with highlighting the importance of aerosol radiative impact under the climate change.

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

10.5194/egusphere-egu21-7405 ◽

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

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&#176;N, 68.8&#176;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.&#160;Excess biomass burning chemical tracers such as CO, HCN, H2CO, C2H6, and NH3 were&#160; 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&#160; detected in PM10. The measured shortwave radiative forcing was -36.7 W/m2 at 78&#176; solar zenith angle (SZA) for AOD=0.626.MODTRAN6.0 radiative transfer model (Berk et al., 2014) was used to estimate the aerosol radiative effect and the heating rate profiles at 78&#176; 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&#160; aerosol heating rate (+0.5 K/day) was&#160; 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.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.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.

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Sensitivity of dust radiative forcing to representation of aerosol size distribution in radiative transfer model

Journal of Quantitative Spectroscopy and Radiative Transfer ◽

10.1016/j.jqsrt.2018.04.037 ◽

2018 ◽

Vol 219 ◽

pp. 292-303 ◽

Cited By ~ 3

Author(s):

Yiran Peng ◽

Jian-Qi Zhao ◽

Zhian Sun ◽

Wenjie Zhao ◽

Xiaodong Wei ◽

...

Keyword(s):

Radiative Transfer ◽

Size Distribution ◽

Radiative Forcing ◽

Radiative Transfer Model ◽

Aerosol Size Distribution ◽

Transfer Model

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Contrasting the direct radiative effect and direct radiative forcing of aerosols

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-5513-2014 ◽

2014 ◽

Vol 14 (11) ◽

pp. 5513-5527 ◽

Cited By ~ 105

Author(s):

C. L. Heald ◽

D. A. Ridley ◽

J. H. Kroll ◽

S. R. H. Barrett ◽

K. E. Cady-Pereira ◽

...

Keyword(s):

Energy Balance ◽

Radiative Forcing ◽

Transport Model ◽

Radiative Transfer Model ◽

Transfer Model ◽

Radiative Effect ◽

Chemical Transport Model ◽

Anthropogenic Aerosols ◽

Anthropogenic Aerosol ◽

Direct Radiative Forcing

Abstract. The direct radiative effect (DRE) of aerosols, which is the instantaneous radiative impact of all atmospheric particles on the Earth's energy balance, is sometimes confused with the direct radiative forcing (DRF), which is the change in DRE from pre-industrial to present-day (not including climate feedbacks). In this study we couple a global chemical transport model (GEOS-Chem) with a radiative transfer model (RRTMG) to contrast these concepts. We estimate a global mean all-sky aerosol DRF of −0.36 Wm−2 and a DRE of −1.83 Wm−2 for 2010. Therefore, natural sources of aerosol (here including fire) affect the global energy balance over four times more than do present-day anthropogenic aerosols. If global anthropogenic emissions of aerosols and their precursors continue to decline as projected in recent scenarios due to effective pollution emission controls, the DRF will shrink (−0.22 Wm−2 for 2100). Secondary metrics, like DRE, that quantify temporal changes in both natural and anthropogenic aerosol burdens are therefore needed to quantify the total effect of aerosols on climate.

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

Annales Geophysicae ◽

10.1007/s00585-995-0413-4 ◽

1995 ◽

Vol 13 (4) ◽

pp. 413-418 ◽

Cited By ~ 29

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.

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Contrasting Mineral Dust Abundances from X-Ray Diffraction and Reflectance Spectroscopy

10.5194/amt-2021-431 ◽

2021 ◽

Author(s):

Mohammad R. Sadrian ◽

Wendy M. Calvin ◽

John McCormack

Keyword(s):

Radiative Forcing ◽

Mineral Dust ◽

Reflectance Spectroscopy ◽

Urban Setting ◽

Dust Particles ◽

Radiative Transfer Model ◽

Transfer Model ◽

X Ray Diffraction ◽

Atmospheric Dust ◽

X Ray

Abstract. Mineral dust particles dominate aerosol mass in the atmosphere and directly modify Earth’s radiative balance through absorption and scattering. This radiative forcing varies strongly with mineral composition, yet there is still limited knowledge on the mineralogy of atmospheric dust. In this study, we performed X-ray diffraction (XRD) and reflectance spectroscopy measurements on 37 different atmospheric dust samples collected as airfall in an urban setting to determine mineralogy and the relative proportions of minerals in the dust mixture. Most commonly, XRD has been used to characterize dust mineralogy; however, without prior special sample preparation, this technique is less effective for identifying poorly crystalline or amorphous phases. In addition to XRD measurements, we performed visible, near-infrared, and short-wave infrared (VNIR/SWIR) reflectance spectroscopy for these natural dust samples as a complementary technique to determine minerology and mineral abundances. Reflectance spectra of dust particles are a function of a nonlinear combination of mineral abundances in the mixture. Therefore, we used a Hapke radiative transfer model along with a linear spectral mixing approach to derive relative mineral abundances from reflectance spectroscopy. We compared spectrally derived abundances with those determined semi-quantitatively from XRD. Our results demonstrate that total clay mineral abundances from XRD are correlated with those from reflectance spectroscopy and follow similar trends; however, XRD underpredicts the total amount of clay for many of the samples. On the other hand, calcite abundances are significantly underpredicted by SWIR compared to XRD. This is caused by the weakening of absorption features associated with the fine particle size of the samples, as well as the presence of dark non-mineral materials (e.g., asphalt) in these samples. Another possible explanation for abundance discrepancies between XRD and SWIR is related to the differing sensitivity of the two techniques (crystal structure vs chemical bonds). Our results indicate that it is beneficial to use both XRD and reflectance spectroscopy to characterize airfall dust, because the former technique is good at identifying and quantifying the SWIR-transparent minerals (e.g., quartz, albite, and microcline), while the latter technique is superior for determining abundances for clays and non-mineral components.

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

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-2415-2013 ◽

2013 ◽

Vol 13 (1) ◽

pp. 2415-2456 ◽

Cited By ~ 3

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.

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A simple model for cloud radiative forcing

Atmospheric Chemistry and Physics ◽

10.5194/acp-9-5751-2009 ◽

2009 ◽

Vol 9 (15) ◽

pp. 5751-5758 ◽

Cited By ~ 37

Author(s):

T. Corti ◽

T. Peter

Keyword(s):

Energy Balance ◽

Simple Model ◽

Radiative Transfer ◽

Radiative Forcing ◽

Radiative Transfer Model ◽

Transfer Model ◽

Cloud Radiative Forcing ◽

Wide Range ◽

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, covering a global range of conditions. 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 convenient estimate of cloud radiative forcing for a wide range of conditions, the evaluation of the sensitivity to changes in environmental conditions, and as a tool in education. An online version of the model is available at http://www.iac.ethz.ch/url/crf.

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Interpreting the Ultraviolet Aerosol Index observed with the OMI satellite instrument to understand absorption by organic aerosols: implications for atmospheric oxidation and direct radiative effects

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-27405-2015 ◽

2015 ◽

Vol 15 (19) ◽

pp. 27405-27447

Author(s):

M. S. Hammer ◽

R. V. Martin ◽

A. van Donkelaar ◽

V. Buchard ◽

O. Torres ◽

...

Keyword(s):

Radiative Transfer ◽

South America ◽

Biomass Burning ◽

Southern Africa ◽

Radiative Forcing ◽

Transport Model ◽

Organic Aerosol ◽

Radiative Transfer Model ◽

Transfer Model ◽

Aerosol Index

Abstract. Satellite observations of the Ultraviolet Aerosol Index (UVAI) are sensitive to absorption of solar radiation by aerosols; this absorption affects photolysis frequencies and radiative forcing. We develop a global simulation of the UVAI using the 3-D chemical transport model GEOS-Chem coupled with the Vector Linearized Discrete Ordinate Radiative Transfer model (VLIDORT). The simulation is applied to interpret UVAI observations from the Ozone Monitoring Instrument (OMI) for the year 2007. Simulated and observed values are highly consistent in regions where mineral dust dominates the UVAI, but a large negative bias (−0.32 to −0.97) exists between simulated and observed values in biomass burning regions. We determine effective optical properties for absorbing organic aerosol, known as brown carbon (BrC), and implement them into GEOS-Chem to better represent observed UVAI values over biomass burning regions. The addition of absorbing BrC decreases the mean bias between simulated and OMI UVAI values from −0.57 to −0.09 over West Africa in January, from −0.32 to +0.0002 over South Asia in April, from −0.97 to −0.22 over southern Africa in July, and from −0.50 to +0.33 over South America in September. The spectral dependence of absorption after adding BrC to the model is broadly consistent with reported observations for biomass burning aerosol, with Absorbing Angstrom Exponent (AAE) values ranging from 2.9 in the ultraviolet (UV) to 1.3 across the UV-Near IR spectrum. We assess the effect of the additional UV absorption by BrC on atmospheric photochemistry by examining tropospheric hydroxyl radical (OH) concentrations in GEOS-Chem. The inclusion of BrC decreases OH by up to 35 % over South America in September, up to 25 % over southern Africa in July, and up to 20 % over other biomass burning regions. Global annual mean OH concentrations in GEOS-Chem decrease due to the presence of absorbing BrC, increasing the methyl chloroform lifetime from 5.62 to 5.68 years, thus reducing the bias against observed values. We calculate the direct radiative effect (DRE) of BrC using GEOS-Chem coupled with the radiative transfer model RRTMG (GC-RT). Treating organic aerosol as containing absorbing BrC rather than as primarily scattering changes global annual mean all-sky top of atmosphere (TOA) DRE by +0.05 W m-2 and all-sky surface DRE by −0.06 W m-2. Regional changes of up to +0.5 W m-2 at TOA and down to −1 W m-2 at the surface are found over major biomass burning regions.

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