Solar wind-atmospheric electricity-cloud microphysics connections to weather and climate

Lam, Mai Mai; Tinsley, Brian A.

doi:10.1016/j.jastp.2015.10.019

Cited by 63 publications

(73 citation statements)

References 82 publications

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“…Such microphysical changes in turn affect cloud albedo, cloud opacity, cloud cover, and storm invigoration for later stages of cloud development (Rosenfeld et al, , ; Tinsley, ; Twomey, ). The modulation of the scavenging of cloud condensation nuclei and ice‐forming nuclei by variation of the charges on aerosol particles and droplets may be the reason for observed links between small changes in the global electric circuit current density and small changes in high‐latitude clouds and atmospheric dynamics (Frederick, , ; Frederick & Tinsley, ; Lam et al, , , ; Lam & Tinsley, ; Zhou et al, ). Whether or not this is so, the continuous average electrical effects are a basic microphysical cloud process, the effects of which may prove relevant to general aerosol‐cloud interactions.…”

Section: Introductionmentioning

confidence: 99%

Parameterization of In‐Cloud Aerosol Scavenging Due to Atmospheric Ionization: Part 3. Effects of Varying Droplet Radius

2018

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A new set of simulations of collision rate coefficients for aerosol particles with droplets (in‐cloud scavenging) extends to a droplet radius of 15 μm, with short‐range effects on collisions treated as an increment of droplet effective collision radius (ECR). The simulations are made with our Monte Carlo trajectory model for midtropospheric (~5 km) conditions. The use of ECR allows the results to be expressed as a modified analytic solution (MAS) for the rate coefficients, incorporating both long‐range and short‐range effects. For smaller particles with radius less than 0.2 μm, the increment of ECR is only caused by the particle charge inducing a short‐range image electric force, and results of the MAS match quite well that of our trajectory model. For larger particles, the short‐range effects become complex, including particle size effects (weight, intercept, and flow around the particle), with image forces induced by both droplet and particle charges. An ECR based on these factors gives average errors between the MAS and the trajectory model of less than 10%, with smaller errors for larger droplets. We have now completed the parameterizations of rate coefficients for midtropospheric conditions that can be applied to cloud models. One application would be to test whether electrically induced changes in scavenging rates, which have been proposed to significantly affect cloud processes dependent on condensation nucleus concentration and contact ice nucleation, can explain observed cloud responses to changes in current flow in the global electric circuit.

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Section: Introductionmentioning

confidence: 99%

Parameterization of In‐Cloud Aerosol Scavenging Due to Atmospheric Ionization: Part 3. Effects of Varying Droplet Radius

2018

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“…An additional source of energy comes from the solar wind (SW). In particular, SW energy can be partially converted in magnetohydrodynamic ultralow frequency fluctuations (ULF, 1 mHz–5 Hz), which propagate inside the magnetosphere, and can lead to diffusion and precipitation of relativistic electrons (>100 keV) from the radiation belts [ Regi et al , ; Mann et al , ; Blum et al , ; Rodger et al , ], with potential effects on the atmospheric dynamics (see Mironova et al [] and Lam and Tinsley [] for a review).…”

Section: Introductionmentioning

confidence: 99%

“…In particular, during highly perturbed geomagnetic conditions, the energy transferred to the Earth system could be significant, playing a role in controlling the atmospheric parameter variations [ Francia et al , ; de Wit and Watermann , ] and cloud processes, during which there is a continuous conversion of energy between different forms (e.g., thermal energy to latent heat release). It is a matter of fact that water vapor converts into cloud via several mechanisms (see Tinsley and Yu [] and Lam and Tinsley [] for a review).…”

Section: Introductionmentioning

confidence: 99%

ULF geomagnetic activity effects on tropospheric temperature, specific humidity, and cloud cover in Antarctica, during 2003–2010

et al. 2017

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In the present study we investigated the possible relationship between the ULF geomagnetic activity and the variations of several atmospheric parameters. In particular, we compared the ULF activity in the Pc1‐2 frequency band (100 mHz–5 Hz), computed from geomagnetic field measurements at Terra Nova Bay in Antarctica, with the tropospheric temperature T, specific humidity Q, and cloud cover (high cloud cover, medium cloud cover, and low cloud cover) obtained from reanalysis data set. The statistical analysis was conducted during the years 2003–2010, using correlation and Superposed Epoch Analysis approaches. The results show that the atmospheric parameters significantly change following the increase of geomagnetic activity within 2 days. These changes are evident in particular when the interplanetary magnetic field Bz component is oriented southward (Bz<0) and the By component duskward (By>0). We suggest that both the precipitation of electrons induced by Pc1‐2 activity and the intensification of the polar cap potential difference, modulating the microphysical processes in the clouds, can affect the atmosphere conditions.

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“…This process results in ultrafine aerosol particles of a few nanometers radius which may grow large enough in the presence of low-volatility organic compounds in the atmosphere to act as CCN [Tröstl et al, 2016]. Whatever the source of CCN and IFN, the modulation of the scavenging of CCN and IFN and the ultrafines, by variations of the charges on the particles, may be the reason of observed links between the global electric circuit current density and changes in atmospheric dynamics [Lam and Tinsley, 2016].Simulated collision rates between charged aerosol particles and charged droplets have been parameterized by Tinsley and Zhou [2015], for particle radii in the range 0.004 to 2.0 μm and droplet radii of 3 μm, 6 μm, and 15 μm, and a wide range of droplet and particle charges, but only for 100% relative humidity and particle density of 500 kg m À3 . The present work extends the simulations and parameterization for 3 μm radius ZHANG AND TINSLEY PARAMETERIZATION OF AEROSOL SCAVENGING 5330Key Points:• Atmospheric electric charge affects particle scavenging rates in clouds • Extensive simulations are given of scavenging by 3 μm radius droplets with varying relative humidity • The results have been parameterized for incorporation into cloud models PARAMETERIZATION OF AEROSOL SCAVENGING R Q,0,RH from R 0,0,RH , which represents the effect of image charge induced by droplet's charges.…”

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confidence: 99%

Parameterization of aerosol scavenging due to atmospheric ionization under varying relative humidity

Zhang

Tinsley

2017

JGR Atmospheres

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Simulations and parameterizations of the modulation of aerosol scavenging by electric charges on particles and droplets for different relative humidities have been made for 3 μm radii droplets and a wide range of particle radii. For droplets and particles with opposite‐sign charges, the attractive Coulomb force increases the collision rate coefficients above values due to other forces. With same‐sign charges, the repulsive Coulomb force decreases the rate coefficients, and the short‐range attractive image forces become important. The phoretic forces are attractive for relative humidity less than 100% and repulsive for relative humidity greater than 100% and have increasing overall effect for particle radii up to about 1 μm. There is an analytic solution for rate coefficients if only inverse square forces are present, but due to the presence of image forces, and for larger particles the intercept, weight, and the flow around the particle affecting the droplet trajectory, the simulated results usually depart far from the analytic solution. We give simple empirical parameterization formulas for some cases and more complex parameterizations for more exact fits to the simulated results. The results can be used in cloud models with growing droplets, as in updrafts, as well as with evaporating droplets in downdrafts. There is considered to be little scavenging of uncharged ice‐forming nuclei in updrafts, but with charged ice‐forming nuclei it is possible for scavenging in updrafts in cold clouds to produce contact ice nucleation. Scavenging in updrafts below the freezing level produces immersion nuclei that promote enhanced freezing as droplets rise above it.

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Solar wind-atmospheric electricity-cloud microphysics connections to weather and climate

Cited by 63 publications

References 82 publications

Parameterization of In‐Cloud Aerosol Scavenging Due to Atmospheric Ionization: Part 3. Effects of Varying Droplet Radius

Parameterization of In‐Cloud Aerosol Scavenging Due to Atmospheric Ionization: Part 3. Effects of Varying Droplet Radius

ULF geomagnetic activity effects on tropospheric temperature, specific humidity, and cloud cover in Antarctica, during 2003–2010

Parameterization of aerosol scavenging due to atmospheric ionization under varying relative humidity

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