Absorption of aerosols above clouds from POLDER/PARASOL measurements and estimation of their direct radiative effect

Peers, Fanny; Waquet, Fabien; Cornet, Céline; Dubuisson, P.; Ducos, Fabrice; Goloub, Philippe; Szczap, Frédéric; Tanré, D.; Thieuleux, F.

doi:10.5194/acp-15-4179-2015

Cited by 72 publications

(136 citation statements)

References 63 publications

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“…In addition, CALIOP underestimates aerosols at altitudes above 4 km (Watson‐Parris et al, ). Although the regional cloudy‐sky radiative effects of ari can be strongly positive (de Graaf et al, ; Keil & Haywood, ; Peers et al, ), a small globally averaged cloudy‐sky RFari is expected because most of anthropogenic aerosols are located in the planetary boundary layer, where their RFari is masked by dense water clouds or partially masked by ice clouds. Indeed, GCMs tend to put too much aerosol mass aloft compared to CALIOP vertical aerosol extinction profiles (Koffi et al, ), so even the small cloudy‐sky RFari reported by Schulz et al () may be an overestimate.…”

Section: Rf Of Aerosol‐radiation Interactionsmentioning

confidence: 99%

Bounding Global Aerosol Radiative Forcing of Climate Change

Bellouin

Quaas

Gryspeerdt

et al. 2020

Reviews of Geophysics

587

348

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Aerosols interact with radiation and clouds. Substantial progress made over the past 40 years in observing, understanding, and modeling these processes helped quantify the imbalance in the Earth's radiation budget caused by anthropogenic aerosols, called aerosol radiative forcing, but uncertainties remain large. This review provides a new range of aerosol radiative forcing over the industrial era based on multiple, traceable, and arguable lines of evidence, including modeling approaches, theoretical considerations, and observations. Improved understanding of aerosol absorption and the causes of trends in surface radiative fluxes constrain the forcing from aerosol‐radiation interactions. A robust theoretical foundation and convincing evidence constrain the forcing caused by aerosol‐driven increases in liquid cloud droplet number concentration. However, the influence of anthropogenic aerosols on cloud liquid water content and cloud fraction is less clear, and the influence on mixed‐phase and ice clouds remains poorly constrained. Observed changes in surface temperature and radiative fluxes provide additional constraints. These multiple lines of evidence lead to a 68% confidence interval for the total aerosol effective radiative forcing of ‐1.6 to ‐0.6 W m−2, or ‐2.0 to ‐0.4 W m−2 with a 90% likelihood. Those intervals are of similar width to the last Intergovernmental Panel on Climate Change assessment but shifted toward more negative values. The uncertainty will narrow in the future by continuing to critically combine multiple lines of evidence, especially those addressing industrial‐era changes in aerosol sources and aerosol effects on liquid cloud amount and on ice clouds.

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Section: Rf Of Aerosol‐radiation Interactionsmentioning

confidence: 99%

Bounding Global Aerosol Radiative Forcing of Climate Change

Bellouin

Quaas

Gryspeerdt

et al. 2020

Reviews of Geophysics

587

348

View full text Add to dashboard Cite

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“…Nair et al, 2013). Absorbing aerosols above clouds (AACs) also create a positive DRE at TOA since aerosols absorb cloud reflection Chand et al, 2009;Peters et al, 2011;Jethva et al, 2013;Meyer et al, 2013Meyer et al, , 2015Zhang et al, 2014Zhang et al, , 2016Feng and Christopher, 2015;Peers et al, 2015). Additionally, the presence of AACs can lead to an underestimation of cloud optical thickness (COT) retrieval at visible wavelengths compared to the retrieval of COT in a pristine cloudy scene (Haywood et al, 2004;Coddington et al, 2010;Meyer et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

The impact of seasonalities on direct radiative effects and radiative heating rates of absorbing aerosols above clouds

Chang

Christopher

2017

Quart J Royal Meteoro Soc

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The impact of seasonalities on direct radiative effects (DREs) and radiative heating rates (RHRs) of absorbing aerosols above clouds in the southeast Atlantic is examined using radiative transfer calculations. For an aerosol optical thickness of 0.6 located between 0 and 4 km, a cloud optical thickness of 9.0 and a cloud effective radius of 12.8 µm at 0.55 µm located between 1 and 2 km, the diurnally averaged RHR at noon in the aerosol layer increases from ∼6.6 K day−1 in June to ∼8.9 K day−1 in October. In June (October), the RHR in the cloud layer at noon is 1.3 (1.7) K day−1 higher than the case of pristine clouds. However, an elevated aerosol layer (2–4 km) reduces the RHR by ∼0.2 K day−1 in the cloud layer relative to a pristine cloudy case. The DRE at top‐of‐atmosphere (TOA) reaches its peak when the solar zenith angle (SZA) is 54°. The DRE increases (decreases) with SZA for SZA less (greater) than 54°. The primary peak DRE is ∼29.5 W m−2 at 5.0°S 5.0°E, occurring at 0800 UTC. At noon, the DRE at TOA is ∼18.9, ∼20.5 and ∼23.1 W m−2 at 5.0°S, 15.0°S and 25.0°S along 5.0°E, respectively. This study provides data and theoretical understanding to help positioning science flights that target measurements of above‐cloud aerosol radiative effects.

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“…Above highly reflective clouds, their Direct Radiative Effect (DRE) is usually positive because aerosol absorption reduces local planetary albedo. Recent studies based on remote sensing observations have shown that the DRE of Above‐Cloud Aerosols (ACA) is typically strong over the SEAO and can reach instantaneous values larger than +130 Wm −2 [ DeGraaf et al , ; Peers et al , ]. However, global aerosol models do not reproduce such high DRE [ DeGraaf et al , ].…”

Section: Introductionmentioning

confidence: 99%

Comparison of aerosol optical properties above clouds between POLDER and AeroCom models over the South East Atlantic Ocean during the fire season

Peers

Bellouin

Waquet

et al. 2016

Geophysical Research Letters

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Aerosol properties above clouds have been retrieved over the South East Atlantic Ocean during the fire season 2006 using satellite observations from POLDER (Polarization and Directionality of Earth Reflectances). From June to October, POLDER has observed a mean Above‐Cloud Aerosol Optical Thickness (ACAOT) of 0.28 and a mean Above‐Clouds Single Scattering Albedo (ACSSA) of 0.87 at 550 nm. These results have been used to evaluate the simulation of aerosols above clouds in five Aerosol Comparisons between Observations and Models (Goddard Chemistry Aerosol Radiation and Transport (GOCART), Hadley Centre Global Environmental Model 3 (HadGEM3), European Centre Hamburg Model 5‐Hamburg Aerosol Module 2 (ECHAM5‐HAM2), Oslo‐Chemical Transport Model 2 (OsloCTM2), and Spectral Radiation‐Transport Model for Aerosol Species (SPRINTARS)). Most models do not reproduce the observed large aerosol load episodes. The comparison highlights the importance of the injection height and the vertical transport parameterizations to simulate the large ACAOT observed by POLDER. Furthermore, POLDER ACSSA is best reproduced by models with a high imaginary part of black carbon refractive index, in accordance with recent recommendations.

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Absorption of aerosols above clouds from POLDER/PARASOL measurements and estimation of their direct radiative effect

Cited by 72 publications

References 63 publications

Bounding Global Aerosol Radiative Forcing of Climate Change

Bounding Global Aerosol Radiative Forcing of Climate Change

The impact of seasonalities on direct radiative effects and radiative heating rates of absorbing aerosols above clouds

Comparison of aerosol optical properties above clouds between POLDER and AeroCom models over the South East Atlantic Ocean during the fire season

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