Anna Possner

Anna Possner
Carnegie Institution for Science · Department of Global Ecology

Master of Mathematical Physics (University of Edinburgh)

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26
Publications
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503
Citations

Publications

Publications (26)
Article
Full-text available
Ship tracks provide an ideal test bed for studying aerosol–cloud interactions (ACIs) and for evaluating their representation in model parameterisations. Regional modelling can be of particular use for this task, as this approach provides sufficient resolution to resolve the structure of the produced track including their meteorological environment...
Article
Full-text available
Many regional forecasting models struggle to simulate low-lying strong temperature inversions. To understand this apparent deficit for forecast improvements, a case study of a strong inversion occurring in the Bay of Biscay on 27 January 2003 is conducted. The event was characterized by extensive stratocumulus cloud cover beneath an extensive high...
Article
Full-text available
Aerosol–cloud interactions (ACIs) are considered to be the most uncertain driver of present-day radiative forcing due to human activities. The nonlinearity of cloud-state changes to aerosol perturbations make it challenging to attribute causality in observed relationships of aerosol radiative forcing. Using correlations to infer causality can be ch...
Preprint
Full-text available
Marine stratocumuli are the most dominant cloud type by area coverage in the Southern Ocean (SO). They can be divided into different self-organized cellular morphological regimes known as open and closed mesoscale-cellular convec- tive (MCC) clouds. Open and closed cells are the two most frequent types of organizational regimes in the SO. Using the...
Preprint
Full-text available
Aerosol-cloud interactions (ACI) are considered to be the most uncertain driver of present-day radiative forcing due to human activities. The non-linearity of cloud-state changes to aerosol perturbations make it challenging to attribute causality in observed relationships of aerosol radiative forcing. Using correlations to infer causality can also...
Article
Full-text available
The Arctic is known to be particularly sensitive to climate change. This Arctic amplification has partially been attributed to poleward atmospheric heat transport in the form of air mass intrusions. Locally, such air mass intrusions can introduce moisture and temperature perturbations. The effect of air mass perturbations on boundary layer and clou...
Article
Full-text available
The liquid water path (LWP) adjustment due to aerosol–cloud interactions in marine stratocumulus remains a considerable source of uncertainty for climate sensitivity estimates. An unequivocal attribution of LWP adjustments to changes in aerosol concentration from climatology remains difficult due to the considerable covariance between meteorologica...
Article
Full-text available
Aerosols interact with radiation and clouds. Substantial progress made over the past 40 years in observing, understanding, and modeling these processes helped quantify the imbalance in the Earth's radiation budget caused by anthropogenic aerosols, called aerosol radiative forcing, but uncertainties remain large. This review provides a new range of...
Article
Full-text available
The influence of aerosol particles on cloud reflectivity remains one of the largest sources of uncertainty in our understanding of anthropogenic climate change. Commercial shipping constitutes a large and concentrated aerosol perturbation in a meteorological regime where clouds have a disproportionally large effect on climate. Yet, to date, studies...
Article
Full-text available
Plain Language Summary Low‐lying clouds have been found to organize into honeycomb‐like spatial patterns. This has been primarily studied for liquid clouds in the subtropical regions but has remained unexplored in the high latitudes. Previous studies focusing on precipitating open‐cell clouds have found that below cloud base a continuous cycle of e...
Preprint
Full-text available
The liquid water path (LWP) adjustment due to aerosol-cloud interactions in marine stratocumuli remains a considerable source of uncertainty for climate sensitivity estimates. An unequivocal attribution of LWP changes to changes in aerosol concentration from climatology remains difficult due to the considerable covariance between meteorological con...
Article
Full-text available
The formation and persistence of low-lying mixed-phase clouds (MPCs) in the Arctic depends on a multitude of processes, such as surface conditions, the environmental state, air mass advection, and the ambient aerosol concentration. In this study, we focus on the relative importance of different instantaneous aerosol perturbations (cloud condensatio...
Article
Human activities produce tiny airborne particles called aerosols. The discovery that the average impact of these aerosols on the water content of low-level clouds is minimal will lead to more-reliable models of future climate. A key constraint on the overall cooling effect of aerosol emissions.
Article
Full-text available
Aerosol–cloud radiative effects are determined and quantified in simulations of deep open-cell stratocumuli observed during the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) campaign off the west coast of Chile. The cloud deck forms in a boundary layer 1.5km deep, with cell sizes reaching 50km in diameter. Global database...
Article
Full-text available
The formation and persistence of low lying mixed-phase clouds (MPCs) in the Arctic depends on a multitude of processes, such as surface conditions, the environmental state, air mass advection and the ambient aerosol concentration. In this study, we focus on the relative importance of different aerosol perturbations (cloud condensation nuclei and ic...
Article
Full-text available
We perform a model intercomparison of summertime high Arctic ( > 80°N) clouds observed during the 2008 Arctic Summer Cloud Ocean Study (ASCOS) campaign, when observed cloud condensation nuclei (CCN) concentrations fell below 1cm⁻³. Previous analyses have suggested that at these low CCN concentrations the liquid water content (LWC) and radiative pro...
Article
Full-text available
Aerosol-cloud-radiative effects are determined and quantified in simulations of deep open-cell stratocumuli observed during the VOCALS-REx campaign off the West coast of Chile. The cloud deck forms in a 1.5km deep boundary layer with cell sizes reaching 50km in diameter. Global data bases of ship tracks suggest that these linear structures are seld...
Article
Full-text available
We perform a model intercomparison of summertime high Arctic (> 80 N) clouds observed during the 2008 Arctic Summer Cloud Ocean Study (ASCOS) campaign, when observed cloud condensation nuclei (CCN) concentrations fell below 1 cm−3. Previous analyses have suggested that at these low CCN concentrations the liquid water content (LWC) and radiative pro...
Article
Full-text available
Wind turbines continuously remove kinetic energy from the lower troposphere, thereby reducing the wind speed near hub height. The rate of electricity generation in large wind farms containing multiple wind arrays is, therefore, constrained by the rate of kinetic energy replenishment from the atmosphere above. In recent years, a growing body of rese...
Article
Full-text available
The complexity of atmospheric aerosol causes large uncertainties in its parameterization in atmospheric models. In a process-based comparison of two aerosol and chemistry schemes within the regional atmospheric modeling framework COSMO-ART (Consortium for Small-Scale Modelling, Aersosol and Reactive Trace gases extension), we identify key sensitivi...
Article
Full-text available
The complexity of the atmospheric aerosol causes large uncertainties in its parameterization in atmospheric models. In a process-based comparison of two aerosol and chemistry schemes within the regional atmospheric modeling framework COSMO-ART, we identify key sensitivities of aerosol parameterizations. We consider the aerosol module MADE in combin...
Article
Full-text available
Stratiform mixed-phase clouds (MPCs), which contain both supercooled liquid and ice, play a key role in the energy balance of the Arctic and are a major contributor to surface precipitation. As Arctic shipping is projected to increase with climate change, these clouds may frequently be exposed to local aerosol perturbations of up to 15âĂŹ000cm−3. Y...
Article
Full-text available
Measures of aerosol-cloud interactions in stratocumulus have been shown to depend on the resolution of the applied data set. In order to contrast resolution with emission dilution effects in models, a regional numerical weather prediction model is used to simulate ship tracks at a range of spatiotemporal resolutions ranging from the global climate...
Article
Full-text available
Ship tracks provide an ideal test bed for studying aerosol-cloud interactions (ACI) and for evaluating their representation in parameterisations. Regional modelling can be of particular use for this task, as this approach provides sufficient resolution to resolve the structure of the produced track including their meteorological environment whilst...

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