Hygroscopic growth study in the framework of EARLINET during the  SLOPE I campaign: synergy of remote sensing and in-situ instrumentation

Bedoya-Velásquez, Andrés Esteban; Navas-Guzmán, Francisco; Granados-Muñoz, María José; Titos, Gloria; Román, Roberto; Casquero-Vera, Juan Andrés; Ortiz-Amezcua, Pablo; Benavent-Oltra, José Antonio; Moreira, Gregory de Arruda; Montilla-Rosero, Elena; Hoyos, Carlos D.; Artı́ñano, Begoña; Coz, Esther; Alados-Arboledas, L.; Guerrero-Rascado, Juan Luís

doi:10.5194/acp-2017-993

Cited by 5 publications

(5 citation statements)

References 29 publications

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“…The number of 10‐min lidar profiles passing layer selection was N = 874 (774 cloud‐free) out of 1,503 (58%) daytime profiles. The layer conditions (shown in Figure S1a–S1c) resemble other studies quantifying lidar retrieved ambient aerosol humidification (Bedoya‐Velásquez et al, 2018; Granados‐Muñoz et al, 2015; Lv et al, 2017).…”

Section: Methodssupporting

confidence: 77%

Ambient Aerosol Hygroscopic Growth From Combined Raman Lidar and HSRL

et al. 2020

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Lidar retrievals of aerosol extinction and collocated relative humidity (RH) were acquired during the Department of Energy Combined High Spectral Resolution Lidar (HSRL) and Raman Measurement Study campaign in the summer of 2015 at the Southern Great Plains site in northern Oklahoma. Measurements of the hygroscopic properties of aerosols are crucial for accurately representing their relationship with clouds, which can be a significant source of uncertainty in assessing direct and indirect radiative effects. The ability for lidar to retrieve measurements of the vertically resolved f (RH), that is, the aerosol extinction at some wet RH normalized by the aerosol extinction at a dry reference RH, is investigated here and compared with nephelometer-measured f (RH) at the surface. We introduce a modified approach to fitting the lidar measurements of aerosol extinction and our comparisons reveal that lidar and nephelometer measurements of f (RH) are consistent, both with each other and with reported values in the literature. The implications for this work present a path forward for global-scale retrievals of remotely sensed aerosol hygroscopic properties. Most importantly, the efforts in this study could lead to closing the gap on uncertainties associated with the aerosol indirect radiative effect when combined with inversion retrievals of aerosol microphysical properties.Plain Language Summary Atmospheric aerosols, or tiny particles suspended in the atmosphere, are an important component of the climate system. These particles can sometimes undergo humidification processes that allow them to grow in size and scatter more solar radiation. When certain conditions are met, aerosols can grow to become cloud droplets and modify cloud properties like brightness or reflectivity. Remote sensing systems can observe optical properties of aerosols on a large scale and in a timely fashion. However, some essential aspects of these aerosols, like their humidification properties, remain a challenge for remote sensing instruments to obtain. In this study, we demonstrate the capability of a unique lidar system to expand the current set of observations that are regularly retrieved by remote sensing instruments. Specifically, we make simultaneous retrievals of the atmospheric relative humidity and aerosol light extinction coefficients by combining Raman and High Spectral Resolution Lidar. We show that this system can accurately retrieve humidification properties of aerosols within the atmospheric mixed layer. These results reach a considerable milestone for the future advancement of remote sensing lidar and represent a path forward in reducing climate forcing uncertainty.

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Section: Methodssupporting

confidence: 77%

Ambient Aerosol Hygroscopic Growth From Combined Raman Lidar and HSRL

et al. 2020

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“…Experimental techniques for particles deposited on substrates, levitated single particles and aerosol particles are reviewed in Sections 3-5, respectively. Remote sensing techniques can also be employed to retrieve aerosol hygroscopicity (Ferrare et al, 1998;Feingold and Morley, 2003;Pahlow et al, 2006;Schuster et al, 2009;Li et al, 2013;Lv et al, 2017;Bedoya-Velasquez et al, 2018;Fernandez et al, 2018); however, they are not covered in this paper because we intend to focus on in-situ techniques and application of remote sensing to investigate aerosol hygroscopicity has been discussed very recently in a book chapter (Kreidenweis and Asa-Awuku, 2014). In addition, techniques for measuring CCN and IN activities of aerosol particles are not covered in the present paper, and interested readers are referred to relevant literature (Roberts and Nenes, 2005;Lance et al, 2006;Petters et al, 2007;Good et al, 2010a;DeMott et al, 2011;Lathem and Nenes, 2011;Hiranuma et al, 2015;Wex et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

A review of experimental techniques for aerosol hygroscopicity studies

Tang¹,

Chan²,

Li³

et al. 2019

Preprint

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<p><strong>Abstract.</strong> Hygroscopicity is one of the most important physicochemical properties of aerosol particles, and also plays indispensable roles in many other scientific and technical fields. A myriad of experimental techniques, which differ in principles, configurations and cost, are available for investigating aerosol hygroscopicity under subsaturated conditions (i.e., relative humidity below 100&#8201;%). A comprehensive review of these techniques is provided in this paper, in which experimental techniques are broadly classified into four categories, according to the way samples under investigation are prepared. For each technique, we describe its operation principle and typical configuration, use representative examples reported in previous work to illustrate how this technique can help better understand aerosol hygroscopicity, and discuss its advantages and disadvantages. In addition, future directions are outlined and discussed for further technical improvement and instrumental development.</p>

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“…A second in situ aerosol site was located on a nearby mountaintop (height difference 1.1 km, Mignani et al, 2021;Wieder et al, 2022b). The near collocation of the lidar beam and the mountaintop site (horizontal displacement 3.65 km) is ideally suited for aerosol and thus INP closure as also previously shown by Bedoya-Velásquez et al (2018), who studied the hygroscopicity of aerosol particles. Based on aerosol data collected over 8 weeks and seven observed cloud events, we address the following.…”

Section: Introductionmentioning

confidence: 93%

Retrieving ice-nucleating particle concentration and ice multiplication factors using active remote sensing validated by in situ observations

Wieder

Ihn²,

Mignani³

et al. 2022

Atmos. Chem. Phys.

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Abstract. Understanding the evolution of the ice phase within mixed-phase clouds (MPCs) is necessary to reduce uncertainties related to the cloud radiative feedback in climate projections and precipitation initiation. Both primary ice formation via ice-nucleating particles (INPs) and secondary ice production (SIP) within MPCs are unconstrained, not least because of the lack of atmospheric observations. In the past decades, advanced remote sensing methods have emerged which provide high-resolution data of aerosol and cloud properties and could be key in understanding microphysical processes on a global scale. In this study, we retrieved INP concentrations and ice multiplication factors (IMFs) in wintertime orographic clouds using active remote sensing and in situ observations obtained during the RACLETS campaign in the Swiss Alps. INP concentrations in air masses dominated by Saharan dust and continental aerosol were retrieved from a polarization Raman lidar and validated with aerosol and INP in situ observations on a mountaintop. A calibration factor of 0.0204 for the global INP parameterization by DeMott et al. (2010) is derived by comparing in situ aerosol and INP measurements, improving the INP concentration retrieval for continental aerosols. Based on combined lidar and radar measurements, the ice crystal number concentration and ice water content were retrieved and validated with balloon-borne in situ observations, which agreed with the balloon-borne in situ observations within an order of magnitude. For seven cloud cases the ice multiplication factors (IMFs), defined as the quotient of the ice crystal number concentration to the INP concentration, were calculated. The median IMF was around 80, and SIP was active (defined as IMFs > 1) nearly 85 % of the time. SIP was found to be active at all observed temperatures (−30 to −5 ∘C), with the highest IMFs between −20 and −5 ∘C. The introduced methodology could be extended to larger datasets to better understand the impact of SIP not only over the Alps but also at other locations and for other cloud types.

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Hygroscopic growth study in the framework of EARLINET during the SLOPE I campaign: synergy of remote sensing and in-situ instrumentation

Cited by 5 publications

References 29 publications

Ambient Aerosol Hygroscopic Growth From Combined Raman Lidar and HSRL

Ambient Aerosol Hygroscopic Growth From Combined Raman Lidar and HSRL

A review of experimental techniques for aerosol hygroscopicity studies

Retrieving ice-nucleating particle concentration and ice multiplication factors using active remote sensing validated by in situ observations

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