Effect of aerosols on the macro- and micro-physical properties of warm clouds in the Beijing-Tianjin-Hebei region

Liu, Tongqiang; Liu, Qiong; Chen, Yonghang; Wang, Wencai; Zhang, Hua; Li, Dui; Sheng, Jun

doi:10.1016/j.scitotenv.2020.137618

Cited by 17 publications

(12 citation statements)

References 38 publications

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“…However, how aerosols modify cloud droplet size remains an open question at present. There exist enough studies showing not only the decrease of cloud droplet size with the increase of aerosols (hereafter referred to as negative relationship) 4 – 6 , but also the increase of cloud droplet size with the increase of aerosols (hereafter referred to as positive relationship) 13 – 15 . The mechanism for the negative relationship is reasonably well understood since long ago 4 , 16 ; however, there exist different arguments for the positive relationship.…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, it has been suggested that the excessive presence of hygroscopic aerosols and/or giant CCN can suppress super saturation and hinder the activation of smaller particles into cloud droplets, leading the positive relationship 20 – 22 . Some studies further showed that intense competition of water vapor due to increased aerosols can lead the evaporation of small cloud droplets, and thereby the positive relationship 14 , 15 . These studies provide a clue that the positive relationship can result from pathways different than the pathway of direct aerosol-cloud interaction, but these pathways are yet to be understood in detail.…”

Section: Introductionmentioning

confidence: 99%

“…To generate qualitative evidences, we have had enough attentions in both data quality and study method. First, unlike the general practice of using satellite observed aerosol data 13 – 15 , we have used high-quality aerosol data available from AERONET 23 , a surface-based aerosol observation network, on noting that (i) the complex 3-D radiative transfer effect in the vicinity of clouds challenges aerosol observations from the space 22 , 24 , (ii) over land areas, where the positive relationships are often noted, the complex surface reflection function further deteriorates the quality of satellite-based aerosol products 25 , and (iii) uncertainties can be large in both small and high values of satellite-based aerosol optical thickness (AOT) due to a difficulty in observing a very pristine atmosphere 26 and separating clouds from aerosols 27 , respectively. Furthermore, the meteorological factors are known to influence aerosol-cloud interaction process significantly 6 , 28 , urging it equally important to disentangle the effects of meteorological factors to understand aerosol-cloud interaction process more precisely.…”

Section: Introductionmentioning

confidence: 99%

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Increased aerosols can reverse Twomey effect in water clouds through radiative pathway

Khatri

Hayasaka

Holben

et al. 2022

Sci Rep

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Aerosols play important roles in modulations of cloud properties and hydrological cycle by decreasing the size of cloud droplets with the increase of aerosols under the condition of fixed liquid water path, which is known as the first aerosol indirect effect or Twomey-effect or microphysical effect. Using high-quality aerosol data from surface observations and statistically decoupling the influence of meteorological factors, we show that highly loaded aerosols can counter this microphysical effect through the radiative effect to result both the decrease and increase of cloud droplet size depending on liquid water path in water clouds. The radiative effect due to increased aerosols reduces the moisture content, but increases the atmospheric stability at higher altitudes, generating conditions favorable for cloud top entrainment and cloud droplet coalescence. Such radiatively driven cloud droplet coalescence process is relatively stronger in thicker clouds to counter relatively weaker microphysical effect, resulting the increase of cloud droplet size with the increase of aerosol loading; and vice-versa in thinner clouds. Overall, the study suggests the prevalence of both negative and positive relationships between cloud droplet size and aerosol loading in highly polluted regions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Increased aerosols can reverse Twomey effect in water clouds through radiative pathway

Khatri

Hayasaka

Holben

et al. 2022

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Satellites provide long-term global coverage that enables ACI studies with constrained meteorology and cloud regimes (Oreopoulos et al, 2017;Douglas and L'Ecuyer, 2019;Jia et al, 2021). Satellite-based ACI studies relate cloud parameters (cloud reflectivity or albedo, cloud optical depth, cloud fraction, cloud drop effective radius, liquid water path), aerosol properties (aerosol optical depth (AOD), Ångström exponent (AE), aerosol index (AI)), and the precipitation pattern to understand the underlying mechanisms (Quaas et al, 2008(Quaas et al, , 2020Gryspeerdt and Stier, 2012;McCoy et al, 2017;Kant et al, 2019;Liu et al, 2020;Choudhury et al, 2020). The use of AOD and (to a lesser extent) AI as CCN proxies results in a significant underestimation of the radiative forcing due to ACIs (Gryspeerdt et al, 2017;Hasekamp et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Estimating cloud condensation nuclei concentrations from CALIPSO lidar measurements

Choudhury

Tesche

2022

Atmos. Meas. Tech.

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Abstract. We present a novel methodology to estimate cloud condensation nuclei (CCN) concentrations from spaceborne CALIPSO (Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations) lidar measurements. The algorithm utilizes (i) the CALIPSO-derived backscatter and extinction coefficient, depolarization ratio, and aerosol subtype information; (ii) the normalized volume size distributions and refractive indices from the CALIPSO aerosol model; and (iii) the MOPSMAP (modelled optical properties of ensembles of aerosol particles) optical modelling package. For each CALIPSO height bin, we first select the aerosol-type specific size distribution and then adjust it to reproduce the extinction coefficient derived from the CALIPSO retrieval. The scaled size distribution is integrated to estimate the aerosol number concentration, which is then used in the CCN parameterizations to calculate CCN concentrations at different supersaturations. To account for the hygroscopicity of continental and marine aerosols, we use the kappa parameterization and correct the size distributions before the scaling step. The sensitivity of the derived CCN concentrations to variations in the initial size distributions is also examined. It is found that the uncertainty associated with the algorithm can range between a factor of 2 and 3. Our results are comparable to results obtained using the POLIPHON (Polarization Lidar Photometer Networking) method for extinction coefficients larger than 0.05 km−1. An initial application to a case with coincident airborne in situ measurements for independent validation shows promising results and illustrates the potential of CALIPSO for constructing a global height-resolved CCN climatology.

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“…Satellites provide long term global coverage that enables ACI studies with constrained meteorology and cloud regimes (Oreopoulos et al, 2017;Douglas and L'Ecuyer, 2019;Jia et al, 2021). Satellite-based ACI studies relate cloud parameters (cloud reflectivity or albedo, cloud optical depth, cloud fraction, cloud drop effective radius, liquid water path), aerosol properties (aerosol optical depth (AOD), angstrom exponent(AE), aerosol index (AI)), and the precipitation pattern, to understand the underlying mechanisms (Quaas et al, 2008;Gryspeerdt and Stier, 2012;McCoy et al, 2017;Kant et al, 2019;Liu et al, 2020;Choudhury et al, 2020;Quaas et al, 2020). Shinozuka et al (2015) suggest that the satellite-derived AOD or AI, being a column integrated product, may not be the appropriate proxies for cloud-relevant CCN particles that usually lie close to the cloud base.…”

Section: Introductionmentioning

confidence: 99%

Estimating cloud condensation nuclei concentrations from CALIPSO lidar measurements

Choudhury

Tesche

2021

Preprint

View full text Add to dashboard Cite

Abstract. We present a novel methodology to estimate cloud condensation nuclei (CCN) concentrations from spaceborne CALIPSO lidar measurements. The algorithm utilizes (i) the CALIPSO-derived backscatter and extinction coefficient, depolarization ratio, and aerosol subtype information, (ii) the normalized volume size distributions and refractive indices from the CALIPSO aerosol model, and (iii) the MOPSMAP optical modelling package. For each CALIPSO height bin, we first select the aerosol-type specific size distribution and then adjust it to reproduce the extinction coefficient derived from the CALIPSO retrieval. The scaled size distribution is integrated to estimate the aerosol number concentration which is then used in the CCN parameterizations to calculate CCN concentrations at different supersaturations. To account for the hygroscopicity of continental and marine aerosols, we use the kappa parameterization and correct the size distributions before the scaling step. We have studied the sensitivity of the thus derived CCN concentration to the effect of variations of the initial size distributions. It is found that the uncertainty associated with the algorithm can range between a factor of 2 and 3. We have also compared our results with the POLIPHON and found comparable results for extinction coefficients larger than 0.05 km−1. An initial application to a case with coincident airborne in-situ measurements for independent validation shows promising results and illustrates the potential of CALIPSO for constructing a global height-resolved CCN climatology.

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Effect of aerosols on the macro- and micro-physical properties of warm clouds in the Beijing-Tianjin-Hebei region

Cited by 17 publications

References 38 publications

Increased aerosols can reverse Twomey effect in water clouds through radiative pathway

Increased aerosols can reverse Twomey effect in water clouds through radiative pathway

Estimating cloud condensation nuclei concentrations from CALIPSO lidar measurements

Estimating cloud condensation nuclei concentrations from CALIPSO lidar measurements

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