Interactive Worksheets for Teaching Atmospheric Aerosols and Cloud Physics

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-20-0072.1 ◽

2020 ◽

pp. 1-40

Author(s):

Markus Petters

Keyword(s):

Atmospheric Aerosols ◽

Cloud Physics ◽

Atmospheric Models ◽

Atmospheric Physics

Capsule summaryApplets allow students to playfully interact with physical relationships and atmospheric models in an inquiry-based course on Atmospheric Physics.

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Impact of Aerosol-Cloud Cycling on Aqueous Secondary Organic Aerosol Formation

Atmosphere ◽

10.3390/atmos10110666 ◽

2019 ◽

Vol 10 (11) ◽

pp. 666 ◽

Cited By ~ 3

Author(s):

William G. Tsui ◽

Joseph L. Woo ◽

V. Faye McNeill

Keyword(s):

Atmospheric Aerosols ◽

Organic Material ◽

Organic Aerosol ◽

Time Of Day ◽

Aerosol Formation ◽

Atmospheric Models ◽

Cloud Processing ◽

Aerosol Mass ◽

Phase Chemistry ◽

The Impact

Chemical processing of organic material in aqueous atmospheric aerosols and cloudwater is known to form secondary organic aerosols (SOA), although the extent to which each of these processes contributes to total aerosol mass is unclear. In this study, we use GAMMA 5.0, a photochemical box model with coupled gas and aqueous-phase chemistry, to consider the impact of aqueous organic reactions in both aqueous aerosols and clouds on isoprene epoxydiol (IEPOX) SOA over a range of pH for both aqueous phases, including cycling between cloud and aerosol within a single simulation. Low pH aqueous aerosol, in the absence of organic coatings or other morphology which may limit uptake of IEPOX, is found to be an efficient source of IEPOX SOA, consistent with previous work. Cloudwater at pH 4 or lower is also found to be a potentially significant source of IEPOX SOA. This phenomenon is primarily attributed to the relatively high uptake of IEPOX to clouds as a result of higher water content in clouds as compared with aerosol. For more acidic cloudwater, the aqueous organic material is comprised primarily of IEPOX SOA and lower-volatility organic acids. Both cloudwater pH and the time of day or sequence of aerosol-to-cloud or cloud-to-aerosol transitions impacted final aqueous SOA mass and composition in the simulations. The potential significance of cloud processing as a contributor to IEPOX SOA production could account for discrepancies between predicted IEPOX SOA mass from atmospheric models and measured ambient IEPOX SOA mass, or observations of IEPOX SOA in locations where mass transfer limitations are expected in aerosol particles.

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Impact of buildings on surface solar radiation over urban Beijing

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-5841-2016 ◽

2016 ◽

Vol 16 (9) ◽

pp. 5841-5852 ◽

Cited By ~ 10

Author(s):

Bin Zhao ◽

Kuo-Nan Liou ◽

Yu Gu ◽

Cenlin He ◽

Wee-Liang Lee ◽

...

Keyword(s):

Atmospheric Aerosols ◽

Early Morning ◽

Solar Flux ◽

Grid Resolution ◽

Building Structures ◽

Atmospheric Models ◽

Urban Dispersion ◽

Surface Solar Radiation ◽

Plane Parallel ◽

The Impact

Abstract. The rugged surface of an urban area due to varying buildings can interact with solar beams and affect both the magnitude and spatiotemporal distribution of surface solar fluxes. Here we systematically examine the impact of buildings on downward surface solar fluxes over urban Beijing by using a 3-D radiation parameterization that accounts for 3-D building structures vs. the conventional plane-parallel scheme. We find that the resulting downward surface solar flux deviations between the 3-D and the plane-parallel schemes are generally ±1–10 W m−2 at 800 m grid resolution and within ±1 W m−2 at 4 km resolution. Pairs of positive–negative flux deviations on different sides of buildings are resolved at 800 m resolution, while they offset each other at 4 km resolution. Flux deviations from the unobstructed horizontal surface at 4 km resolution are positive around noon but negative in the early morning and late afternoon. The corresponding deviations at 800 m resolution, in contrast, show diurnal variations that are strongly dependent on the location of the grids relative to the buildings. Both the magnitude and spatiotemporal variations of flux deviations are largely dominated by the direct flux. Furthermore, we find that flux deviations can potentially be an order of magnitude larger by using a finer grid resolution. Atmospheric aerosols can reduce the magnitude of downward surface solar flux deviations by 10–65 %, while the surface albedo generally has a rather moderate impact on flux deviations. The results imply that the effect of buildings on downward surface solar fluxes may not be critically significant in mesoscale atmospheric models with a grid resolution of 4 km or coarser. However, the effect can play a crucial role in meso-urban atmospheric models as well as microscale urban dispersion models with resolutions of 1 m to 1 km.

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2. Atmospheric physics

The Atmosphere: A Very Short Introduction ◽

10.1093/actrade/9780198722038.003.0002 ◽

2017 ◽

pp. 20-48

Author(s):

Paul I. Palmer

Keyword(s):

Greenhouse Gases ◽

Atmospheric Aerosols ◽

Electrical Energy ◽

Radiation Budget ◽

Radiative Energy ◽

The Sun ◽

Atmospheric Physics ◽

Emit Radiation ◽

Wide Range ◽

Earth’S Radiation Budget

Earth’s atmosphere is tied closely with the Sun. The Sun emits electromagnetic radiation at a wide range of wavelengths. Radiation is transported through the atmosphere by transmission, absorption, and scattering. ‘Atmospheric physics’ outlines the Earth’s radiation budget—the incoming and outgoing radiation, equilibrium between them, and departures from this equilibrium due to increasing levels of clouds, greenhouse gases, and atmospheric aerosols. It then describes the greenhouse gases that absorb and emit radiation and the thermodynamics of the atmosphere. The importance of water, the dominant atmospheric constituent responsible for the loss of radiative energy to space and hence atmospheric cooling, and the electrical energy stored in the atmosphere are also discussed.

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Impact of buildings on surface solar radiation over urban Beijing

10.5194/acp-2016-3 ◽

2016 ◽

Author(s):

B. Zhao ◽

K. N. Liou ◽

Y. Gu ◽

C. He ◽

W. L. Lee ◽

...

Keyword(s):

Atmospheric Aerosols ◽

Early Morning ◽

Solar Flux ◽

Grid Resolution ◽

Building Structures ◽

Atmospheric Models ◽

Urban Dispersion ◽

Surface Solar Radiation ◽

Plane Parallel ◽

The Impact

Abstract. The rugged surface of an urban area due to varying buildings can interact with solar beams and affect both the magnitude and spatiotemporal distribution of surface solar fluxes. Here we systematically examine the impact of buildings on downward surface solar fluxes over urban Beijing by using a 3-D radiation parameterization that accounts for 3-D building structures versus the conventional plane-parallel scheme. We find that the resulting downward surface solar flux deviations between the 3-D and the plane-parallel schemes are generally ±1–10 W m−2 at 800-m grid resolution and within ±1 W m−2 at 4-km resolution. Pairs of positive negative flux deviations on different sides of buildings are resolved at 800-m resolution, while they offset each other at 4-km resolution. Flux deviations from the unobstructed horizontal surface at 4-km resolution are positive around noon but negative in the early morning and late afternoon. The corresponding deviations at 800-m resolution, in contrast, show diurnal variations that are strongly dependent on the location of the grids relative to the buildings. Both the magnitude and spatiotemporal variations of flux deviations are largely dominated by the direct flux. Furthermore, we find that flux deviations can potentially be an order of magnitude larger by using a finer grid resolution. Atmospheric aerosols can reduce the magnitude of downward surface solar flux deviations by 10–65 %, while the surface albedo generally has a rather moderate impact on flux deviations. The results imply that the effect of buildings on downward surface solar fluxes may not be critically significant in mesoscale atmospheric models with a grid resolution of 4 km or coarser. However, the effect can play a crucial role in meso-urban atmospheric models as well as microscale urban dispersion models with resolutions of 1 m–1 km.

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Analysis of Near-Cloud Changes in Atmospheric Aerosols Using Satellite Observations and Global Model Simulations

Remote Sensing ◽

10.3390/rs13061151 ◽

2021 ◽

Vol 13 (6) ◽

pp. 1151

Author(s):

Tamás Várnai ◽

Alexander Marshak

Keyword(s):

Atmospheric Aerosols ◽

Large Scale ◽

Climate Models ◽

Orthogonal Polarization ◽

Atmospheric Models ◽

Moderate Resolution ◽

Resolution Imaging ◽

Moderate Resolution Imaging Spectroradiometer ◽

The Difference ◽

Modern Era

This paper examines cloud-related variations of atmospheric aerosols that occur in partly cloudy regions containing low-altitude clouds. The goal is to better understand aerosol behaviors and to help better represent the radiative effects of aerosols on climate. For this, the paper presents a statistical analysis of a multi-month global dataset that combines data from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) satellite instruments with data from the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) global reanalysis. Among other findings, the results reveal that near-cloud enhancements in lidar backscatter (closely related to aerosol optical depth) are larger (1) over land than ocean by 35%, (2) near optically thicker clouds by substantial amounts, (3) for sea salt than for other aerosol types, with the difference from dust reaching 50%. Finally, the study found that mean lidar backscatter is higher near clouds not because of large-scale variations in meteorological conditions, but because of local processes associated with individual clouds. The results help improve our understanding of aerosol-cloud-radiation interactions and our ability to represent them in climate models and other atmospheric models.

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Retrieving the atmospheric properties of directly imaged planets

10.5194/epsc2020-131 ◽

2020 ◽

Author(s):

Paul Mollière ◽

Keyword(s):

Formation Process ◽

Giant Planets ◽

Analysis Method ◽

Atmospheric Models ◽

Atmospheric Physics ◽

Atmospheric Structure ◽

Cloud Models ◽

Modeling Uncertainties ◽

Gas Giant ◽

Shed Light

<p>Young gas giant planets still glow hot from formation, sometimes even showing signs of active accretion. Studying the atmospheres of these directly imaged planets may help placing constraints on how they formed, which may also shed light on the formation process of the planetary systems they reside in. In general, this may be achieved by connecting atmospheric to planetary composition, and planetary composition to planet formation. In my talk I will present our work that investigates the first step of this process, namely constraining the atmospheric abundances of gas giant exoplanets via free retrievals of GRAVITY, SPHERE and GPI observations. Free retrievals work by parameterizing the atmospheric structure as much as possible when calculating spectra, thereby allowing the data to constrain the atmosphere&#8217;s state. This relaxes the need for a model to fulfill given assumptions which may not accurately describe the atmospheric physics, due to modeling uncertainties and oversimplifications. At the same time caution is required because unphysical atmospheric models can potentially lead to excellent fits to spectroscopic observations. I will show why including clouds and scattering is crucial for the analysis of directly imaged planets, what the effects of using inappropriate cloud models are, and outline the next steps to develop this analysis method further.</p>

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