Investigation of the sulphate‐induced freezing inhibition effect from CloudSat and CALIPSO measurements

Grenier, Patrick; Blanchet, Jean‐Pierre

doi:10.1029/2010jd013905

Cited by 15 publications

(17 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because it can be difficult to accurately separate Arctic aerosol from diamond dust and thin ice clouds using backscatter data (M. Vaughan, personal communication;2016;Grenier and Blanchet, 2010), we focused on CALIPSO liquid-containing clouds. To gain greater confidence in the aerosol classification within the MOONLiT subset, ice clouds were not allowed in those profiles.…”

Section: Calipsomentioning

confidence: 99%

Aerosol indirect effects on the nighttime Arctic Ocean surface from thin, predominantly liquid clouds

et al. 2017

View full text Add to dashboard Cite

Abstract. Aerosol indirect effects have potentially large impacts on the Arctic Ocean surface energy budget, but model estimates of regional-scale aerosol indirect effects are highly uncertain and poorly validated by observations. Here we demonstrate a new way to quantitatively estimate aerosol indirect effects on a regional scale from remote sensing observations. In this study, we focus on nighttime, optically thin, predominantly liquid clouds. The method is based on differences in cloud physical and microphysical characteristics in carefully selected clean, average, and aerosol-impacted conditions. The cloud subset of focus covers just ∼ 5 % of cloudy Arctic Ocean regions, warming the Arctic Ocean surface by ∼ 1-1.4 W m −2 regionally during polar night. However, within this cloud subset, aerosol and cloud conditions can be determined with high confidence using CALIPSO and CloudSat data and model output. This cloud subset is generally susceptible to aerosols, with a polar nighttime estimated maximum regionally integrated indirect cooling effect of ∼ −0.11 W m −2 at the Arctic sea ice surface (∼ 8 % of the clean background cloud effect), excluding cloud fraction changes. Aerosol presence is related to reduced precipitation, cloud thickness, and radar reflectivity, and in some cases, an increased likelihood of cloud presence in the liquid phase. These observations are inconsistent with a glaciation indirect effect and are consistent with either a deactivation effect or less-efficient secondary ice formation related to smaller liquid cloud droplets. However, this cloud subset shows large differences in surface and meteorological forcing in shallow and higher-altitude clouds and between sea ice and openocean regions. For example, optically thin, predominantly liquid clouds are much more likely to overlay another cloud over the open ocean, which may reduce aerosol indirect effects on the surface. Also, shallow clouds over open ocean do not appear to respond to aerosols as strongly as clouds over stratified sea ice environments, indicating a larger influence of meteorological forcing over aerosol microphysics in these types of clouds over the rapidly changing Arctic Ocean.

show abstract

Section: Calipsomentioning

confidence: 99%

Aerosol indirect effects on the nighttime Arctic Ocean surface from thin, predominantly liquid clouds

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Answering this question would shed light on the role played by SVC in atmospheric processes. For instance, the inclusion of organic aerosols, sulfate or nitric acid within nucleating ice crystals would have serious implications for the ability of SVC to dehydrate the upper troposphere, as it has been shown to severely limit water vapor deposition (Krämer et al, 2006;Murray, 2008;Grenier and Blanchet, 2010), and could explain persisting supersaturation in clear air or around SVC (Krämer et al, 2009). …”

Section: Introductionmentioning

confidence: 99%

On the origin of subvisible cirrus clouds in the tropical upper troposphere

et al. 2012

View full text Add to dashboard Cite

Abstract. Spaceborne lidar observations have recently revealed a previously undetected significant population of Subvisible Cirrus (SVC). We show them to be colder than −74 • , with an optical depth below 0.0015 on average. The formation and persistence over time of this new cloud population could be related to several atmospheric phenomena. In this paper, we investigate if these clouds follow the same formation mechanisms as the general tropical cirrus population (including convection and in-situ ice nucleation), or if specific nucleation sites and trace species play a role in their formation. The importance of three scenarios in the formation of the global SVC population is investigated through different approaches that include comparisons with data imaging from several spaceborne instruments and back-trajectories that document the history and behavior of air masses leading to the point in time and space where subvisible cirrus were detected. In order to simplify the study of their formation, we singled out SVC with coherent temperature histories (mean variance lower than 4 K) according to back-trajectories along 5, 10 or 15 days (respectively 58, 25 and 11 % of SVC). Our results suggest that external processes, including local increases in liquid and hygroscopic aerosol concentration (either through biomass burning or volcanic injection forming sulfate-based aerosols in the troposphere or the stratosphere) have very limited short-term or mid-term impact on the SVC population. On the other hand, we find that ∼ 20 % of air masses leading to SVC formation interacted with convective activity 5 days before they led to cloud formation and detection, a number that climbs to 60 % over 15 days. SVC formation appears especially linked to convection over Africa and Central America, more so during JJA than DJF. These results support the view that the SVC population observed by CALIOP is an extension of the general upper tropospheric ice clouds population with its extreme thinness as its only differentiating factor.

show abstract

“…TIC-2A are topped by a substantial layer of very small (radar-unseen) ice crystals (TIC-1). In contrast, TIC-2B are not overlaided by TIC-1 (Grenier et al, 2009;Grenier and Blanchet, 2010). In this paper, TIC-1 and TIC-2A are not differentiated and therefore will be identified as TIC-1/2A.…”

Section: Introductionmentioning

confidence: 99%

“…Clouds play a fundamental role both in modulating atmospheric radiation and the hydrologic cycles. This is particularly critical in the Arctic, where interactions can be enhanced by the presence of aerosols (Grenier and Blanchet, 2010;Morrison et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…The joint detection characteristics of both CloudSat radar and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) lidar recently reveal the existence of two types of ice clouds (TICs) in the Arctic during the polar night and early spring (Grenier et al, 2009;Grenier and Blanchet, 2010). The type refers to the number of active instruments detecting the cloud; ice clouds of type 1 (TIC-1) are only seen by the lidar whereas ice clouds of type 2 (TIC-2) are seen by both the lidar and the radar.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

On the relationship between Arctic ice clouds and polluted air masses over the North Slope of Alaska in April 2008

et al. 2014

View full text Add to dashboard Cite

Abstract. Recently, two types of ice clouds (TICs) properties have been characterized using the Indirect and SemiDirect Aerosol Campaign (ISDAC) airborne measurements (Alaska, April 2008). TIC-2B were characterized by fewer (< 10 L −1 ) and larger (> 110 µm) ice crystals, and a larger ice supersaturation (> 15 %) compared to TIC-1/2A. It has been hypothesized that emissions of SO 2 may reduce the ice nucleating properties of ice nuclei (IN) through acidification, resulting in a smaller concentration of larger ice crystals and leading to precipitation (e.g., cloud regime TIC-2B). Here, the origin of air masses forming the ISDAC TIC-1/2A (1 April 2008) and TIC-2B (15 April 2008) is investigated using trajectory tools and satellite data. Results show that the synoptic conditions favor air masses transport from three potential SO 2 emission sources into Alaska: eastern China and Siberia where anthropogenic and biomass burning emissions, respectively, are produced, and the volcanic region of the Kamchatka/Aleutians. Weather conditions allow the accumulation of pollutants from eastern China and Siberia over Alaska, most probably with the contribution of acidic volcanic aerosol during the TIC-2B period. Observation Monitoring Instrument (OMI) satellite observations reveal that SO 2 concentrations in air masses forming the TIC-2B were larger than in air masses forming the TIC-1/2A. Airborne measurements show high acidity near the TIC-2B flight where humidity was low. These results support the hypothesis that acidic coating on IN could be at the origin of the formation of TIC-2B.

show abstract

Investigation of the sulphate‐induced freezing inhibition effect from CloudSat and CALIPSO measurements

Cited by 15 publications

References 68 publications

Aerosol indirect effects on the nighttime Arctic Ocean surface from thin, predominantly liquid clouds

Aerosol indirect effects on the nighttime Arctic Ocean surface from thin, predominantly liquid clouds

On the origin of subvisible cirrus clouds in the tropical upper troposphere

On the relationship between Arctic ice clouds and polluted air masses over the North Slope of Alaska in April 2008

Contact Info

Product

Resources

About