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Abstract
Cloud droplet size distribution (CDSD) is a critical characteristic for a number of processes related to clouds, considering that cloud droplets are formed in different sizes above the cloud-base. This paper analyzes the in-situ aircraft measurements of CDSDs and aerosol concentration ( N a ) performed in stratiform clouds in Hebei, China, in 2015 to reveal the characteristics of cloud spectral width, commonly known as relative dispersion ( ε , ratio of standard deviation (σ) to mean radius (r) of the CDSD). A new algorithm is developed to calculate the contributions of droplets of different sizes to ε . It is found that small droplets with the size range of 1 to 5.5 μm and medium droplets with the size range of 5.5 to 10 μm are the major contributors to ε, and the medium droplets generally dominate the change of ε. The variation of ε with N a can be well explained by comparing the normalized changes of σ and r ( k σ / σ and k r / r ), rather than k σ and k r only ( k σ is Δσ/Δ N a and k r is Δr/Δ N a ). From the perspective of external factors affecting ε change, the effects of N a and condensation are examined. It is found that ε increases initially and decreases afterward as N a increases, and “condensational broadening” occurs up to 1 km above cloud-base, potentially providing observational evidence for recent numerical simulations in the literature.
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Challenges in constraining anthropogenic aerosol effects on cloud radiative forcing using present-day spatiotemporal variability. Proc Natl Acad Sci U S A 2016; 113:5804-11. [PMID: 26921324 DOI: 10.1073/pnas.1514036113] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A large number of processes are involved in the chain from emissions of aerosol precursor gases and primary particles to impacts on cloud radiative forcing. Those processes are manifest in a number of relationships that can be expressed as factors dlnX/dlnY driving aerosol effects on cloud radiative forcing. These factors include the relationships between cloud condensation nuclei (CCN) concentration and emissions, droplet number and CCN concentration, cloud fraction and droplet number, cloud optical depth and droplet number, and cloud radiative forcing and cloud optical depth. The relationship between cloud optical depth and droplet number can be further decomposed into the sum of two terms involving the relationship of droplet effective radius and cloud liquid water path with droplet number. These relationships can be constrained using observations of recent spatial and temporal variability of these quantities. However, we are most interested in the radiative forcing since the preindustrial era. Because few relevant measurements are available from that era, relationships from recent variability have been assumed to be applicable to the preindustrial to present-day change. Our analysis of Aerosol Comparisons between Observations and Models (AeroCom) model simulations suggests that estimates of relationships from recent variability are poor constraints on relationships from anthropogenic change for some terms, with even the sign of some relationships differing in many regions. Proxies connecting recent spatial/temporal variability to anthropogenic change, or sustained measurements in regions where emissions have changed, are needed to constrain estimates of anthropogenic aerosol impacts on cloud radiative forcing.
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Ching J, Riemer N, West M. Impacts of black carbon mixing state on black carbon nucleation scavenging: Insights from a particle-resolved model. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jd018269] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Koike M, Takegawa N, Moteki N, Kondo Y, Nakamura H, Kita K, Matsui H, Oshima N, Kajino M, Nakajima TY. Measurements of regional-scale aerosol impacts on cloud microphysics over the East China Sea: Possible influences of warm sea surface temperature over the Kuroshio ocean current. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jd017324] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Pandithurai G, Dipu S, Prabha TV, Maheskumar RS, Kulkarni JR, Goswami BN. Aerosol effect on droplet spectral dispersion in warm continental cumuli. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jd016532] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Konwar M, Maheskumar RS, Kulkarni JR, Freud E, Goswami BN, Rosenfeld D. Aerosol control on depth of warm rain in convective clouds. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jd017585] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Freud E, Rosenfeld D. Linear relation between convective cloud drop number concentration and depth for rain initiation. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jd016457] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Khain A, Lynn B. Simulation of a supercell storm in clean and dirty atmosphere using weather research and forecast model with spectral bin microphysics. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2009jd011827] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Hildebrandt A, Eltahir EAB. Using a horizontal precipitation model to investigate the role of turbulent cloud deposition in survival of a seasonal cloud forest in Dhofar. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2008jg000727] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Anke Hildebrandt
- Department of Computational Hydrosystems Leipzig; UFZ Helmholtz Centre for Environmental Research; Leipzig Germany
| | - Elfatih A. B. Eltahir
- Department of Civil and Environmental Engineering; Massachusetts Institute of Technology; Cambridge Massachusetts USA
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Rosenfeld D, Woodley WL, Axisa D, Freud E, Hudson JG, Givati A. Aircraft measurements of the impacts of pollution aerosols on clouds and precipitation over the Sierra Nevada. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd009544] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Lu ML, Feingold G, Jonsson HH, Chuang PY, Gates H, Flagan RC, Seinfeld JH. Aerosol-cloud relationships in continental shallow cumulus. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd009354] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Platnick S, Oreopoulos L. Radiative susceptibility of cloudy atmospheres to droplet number perturbations: 1. Theoretical analysis and examples from MODIS. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd009654] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Simultaneous observations of aerosol-cloud-albedo interactions with three stacked unmanned aerial vehicles. Proc Natl Acad Sci U S A 2008; 105:7370-5. [PMID: 18499803 DOI: 10.1073/pnas.0710308105] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Aerosol impacts on climate change are still poorly understood, in part, because the few observations and methods for detecting their effects are not well established. For the first time, the enhancement in cloud albedo is directly measured on a cloud-by-cloud basis and linked to increasing aerosol concentrations by using multiple autonomous unmanned aerial vehicles to simultaneously observe the cloud microphysics, vertical aerosol distribution, and associated solar radiative fluxes. In the presence of long-range transport of dust and anthropogenic pollution, the trade cumuli have higher droplet concentrations and are on average brighter. Our observations suggest a higher sensitivity of radiative forcing by trade cumuli to increases in cloud droplet concentrations than previously reported owing to a constrained droplet radius such that increases in droplet concentrations also increase cloud liquid water content. This aerosol-cloud forcing efficiency is as much as -60 W m(-2) per 100% percent cloud fraction for a doubling of droplet concentrations and associated increase of liquid water content. Finally, we develop a strategy for detecting aerosol-cloud interactions based on a nondimensional scaling analysis that relates the contribution of single clouds to albedo measurements and illustrates the significance of characterizing cloud morphology in resolving radiometric measurements. This study demonstrates that aerosol-cloud-albedo interactions can be directly observed by simultaneous observations below, in, and above the clouds.
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Lu ML, Seinfeld JH. Effect of aerosol number concentration on cloud droplet dispersion: A large-eddy simulation study and implications for aerosol indirect forcing. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005jd006419] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Hallar AG, Strawa AW, Schmid B, Andrews E, Ogren J, Sheridan P, Ferrare R, Covert D, Elleman R, Jonsson H, Bokarius K, Luu A. Atmospheric Radiation Measurements Aerosol Intensive Operating Period: Comparison of aerosol scattering during coordinated flights. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005jd006250] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Twohy CH. Evaluation of the aerosol indirect effect in marine stratocumulus clouds: Droplet number, size, liquid water path, and radiative impact. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004jd005116] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Conant WC, VanReken TM, Rissman TA, Varutbangkul V, Jonsson HH, Nenes A, Jimenez JL, Delia AE, Bahreini R, Roberts GC, Flagan RC, Seinfeld JH. Aerosol-cloud drop concentration closure in warm cumulus. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003jd004324] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- W. C. Conant
- Department of Environmental Science and Engineering; California Institute of Technology; Pasadena California USA
| | - T. M. VanReken
- Department of Chemical Engineering; California Institute of Technology; Pasadena California USA
| | - T. A. Rissman
- Department of Chemical Engineering; California Institute of Technology; Pasadena California USA
| | - V. Varutbangkul
- Department of Chemical Engineering; California Institute of Technology; Pasadena California USA
| | - H. H. Jonsson
- Center for Interdisciplinary Remotely-Piloted Aircraft Studies; Naval Postgraduate School; Monterey California USA
| | - A. Nenes
- Schools of Earth and Atmospheric Sciences and Chemical and Biomolecular Engineering; Georgia Institute of Technology; Atlanta Georgia USA
| | - J. L. Jimenez
- Department of Chemistry and Biochemistry, Cooperative Institute for Research in Environmental Sciences; University of Colorado; Boulder Colorado USA
| | - A. E. Delia
- Program in Atmospheric and Oceanic Sciences; University of Colorado; Boulder Colorado USA
| | - R. Bahreini
- Department of Environmental Science and Engineering; California Institute of Technology; Pasadena California USA
| | - G. C. Roberts
- Center for Atmospheric Sciences, Scripps Institution of Oceanography; University of California, San Diego; La Jolla California USA
| | - R. C. Flagan
- Department of Environmental Science and Engineering; California Institute of Technology; Pasadena California USA
- Department of Chemical Engineering; California Institute of Technology; Pasadena California USA
| | - J. H. Seinfeld
- Department of Environmental Science and Engineering; California Institute of Technology; Pasadena California USA
- Department of Chemical Engineering; California Institute of Technology; Pasadena California USA
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Liu Y, Daum PH. Anthropogenic aerosols. Indirect warming effect from dispersion forcing. Nature 2002; 419:580-1. [PMID: 12374969 DOI: 10.1038/419580a] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Yangang Liu
- Brookhaven National Laboratory, Upton, New York 11973, USA.
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Twohy CH, Hudson JG, Yum SS, Anderson JR, Durlak SK, Baumgardner D. Characteristics of cloud-nucleating aerosols in the Indian Ocean region. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2000jd900779] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ramanathan V, Crutzen PJ, Lelieveld J, Mitra AP, Althausen D, Anderson J, Andreae MO, Cantrell W, Cass GR, Chung CE, Clarke AD, Coakley JA, Collins WD, Conant WC, Dulac F, Heintzenberg J, Heymsfield AJ, Holben B, Howell S, Hudson J, Jayaraman A, Kiehl JT, Krishnamurti TN, Lubin D, McFarquhar G, Novakov T, Ogren JA, Podgorny IA, Prather K, Priestley K, Prospero JM, Quinn PK, Rajeev K, Rasch P, Rupert S, Sadourny R, Satheesh SK, Shaw GE, Sheridan P, Valero FPJ. Indian Ocean Experiment: An integrated analysis of the climate forcing and effects of the great Indo-Asian haze. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2001jd900133] [Citation(s) in RCA: 1054] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Heymsfield AJ, McFarquhar GM. Microphysics of INDOEX clean and polluted trade cumulus clouds. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2000jd900776] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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