Topic
Anthropogenic cloud
About: Anthropogenic cloud is a research topic. Over the lifetime, 9 publications have been published within this topic receiving 328 citations. The topic is also known as: anthropocloud & homogenitus.
Papers
TL;DR: In this article, the authors used a global aerosol microphysics model to quantify the impact of these volcanic emissions on the cloud albedo radiative forcing under pre-industrial (PI) and present-day (PD) conditions.
Abstract: . Observations and models have shown that continuously degassing volcanoes have a potentially large effect on the natural background aerosol loading and the radiative state of the atmosphere. We use a global aerosol microphysics model to quantify the impact of these volcanic emissions on the cloud albedo radiative forcing under pre-industrial (PI) and present-day (PD) conditions. We find that volcanic degassing increases global annual mean cloud droplet number concentrations by 40% under PI conditions, but by only 10% under PD conditions. Consequently, volcanic degassing causes a global annual mean cloud albedo effect of −1.06 W m−2 in the PI era but only −0.56 W m−2 in the PD era. This non-equal effect is explained partly by the lower background aerosol concentrations in the PI era, but also because more aerosol particles are produced per unit of volcanic sulphur emission in the PI atmosphere. The higher sensitivity of the PI atmosphere to volcanic emissions has an important consequence for the anthropogenic cloud radiative forcing because the large uncertainty in volcanic emissions translates into an uncertainty in the PI baseline cloud radiative state. Assuming a −50/+100% uncertainty range in the volcanic sulphur flux, we estimate the annual mean anthropogenic cloud albedo forcing to lie between −1.16 W m−2 and −0.86 W m−2. Therefore, the volcanically induced uncertainty in the PI baseline cloud radiative state substantially adds to the already large uncertainty in the magnitude of the indirect radiative forcing of climate.
136 citations
1 Dec 2013
TL;DR: In this article, the authors used a global aerosol microphysics model to quantify the impact of these volcanic emissions on the cloud albedo radiative forcing under pre-industrial (PI) and present-day (PD) conditions.
Abstract: . Observations and models have shown that continuously degassing volcanoes have a potentially large effect on the natural background aerosol loading and the radiative state of the atmosphere. We use a global aerosol microphysics model to quantify the impact of these volcanic emissions on the cloud albedo radiative forcing under pre-industrial (PI) and present-day (PD) conditions. We find that volcanic degassing increases global annual mean cloud droplet number concentrations by 40% under PI conditions, but by only 10% under PD conditions. Consequently, volcanic degassing causes a global annual mean cloud albedo effect of −1.06 W m−2 in the PI era but only −0.56 W m−2 in the PD era. This non-equal effect is explained partly by the lower background aerosol concentrations in the PI era, but also because more aerosol particles are produced per unit of volcanic sulphur emission in the PI atmosphere. The higher sensitivity of the PI atmosphere to volcanic emissions has an important consequence for the anthropogenic cloud radiative forcing because the large uncertainty in volcanic emissions translates into an uncertainty in the PI baseline cloud radiative state. Assuming a −50/+100% uncertainty range in the volcanic sulphur flux, we estimate the annual mean anthropogenic cloud albedo forcing to lie between −1.16 W m−2 and −0.86 W m−2. Therefore, the volcanically induced uncertainty in the PI baseline cloud radiative state substantially adds to the already large uncertainty in the magnitude of the indirect radiative forcing of climate.
92 citations
TL;DR: In this article, the DRI instantaneous CCN spectrometer was used to detect anthropogenic CCN production mechanisms and natural CCN could not be detected, while the spectral properties of CCN were investigated.
40 citations
TL;DR: In this article, the evolution of contrail-cirrus and natural cirrus formed by homogeneous nucleation is studied over up to ten hours by means of a Large-Eddy Simulation (LES) model equipped with a Lagrangian ice microphysics module.
Abstract: The evolution of contrail-cirrus and natural cirrus formed by homogeneous nucleation is studied over up to
ten hours by means of a Large-Eddy Simulation (LES) model equipped with a Lagrangian ice microphysics
module. This is the first time that both cloud types are investigated in a single study. Characteristics of their
life cycles depend strongly on the synoptic scenario. Weak, but enduring updraughts allow for the longest life
times of contrail-cirrus. For cirrus clouds, the updraught speed during their formation is most crucial. Once
contrails lose their linear shape they are hardly distinguishable from natural cirrus which makes it difficult
to evaluate the extent and effect of the anthropogenic cloud modification. Despite their different formation
mechanisms (contrails are generated locally and have initially much higher ice crystal number concentrations
than natural cirrus) we could not single out microphysical criteria that could help to distinguish in general
between both cloud types in observations.
35 citations
TL;DR: In this article, a LES model with bin microphysics was used to investigate the aerosol indirect effects of marine stratocumulus clouds that develop under different thermodynamic conditions.
7 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2019 | 2 |
| 2017 | 1 |
| 2013 | 2 |
| 2012 | 2 |
| 2009 | 1 |
| 1991 | 1 |