The following is a set of notes taken a fellow 0bserver, Gatherer314.
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[This is a somewhat extended version] 🙂
A quick note: this area of study is still in its ‘basic research’ stage. It is also worth noting that there are two main point of views; the majority view being weather and climate –> electrification and lightning, and the minority being electrification and lightning –> weather and climate.
While there is undoubtably work of others that deserve a mention, I’ve linked some from three who, imo, have greatly contributed to our understanding of solar activity/electric atmosphere/climate, enjoy…
RYCROFT –
‘A.C./D.C. atmospheric global electric circuit phenomena’
We review the global circuit driven by thunderstorms and electrified rain clouds. With the ionosphere at an equipotential of ~ +250kV with respect to the Earth, the load in the circuit is the fair weather atmosphere; its conductivity is mainly determined by the flux of galactic cosmic rays. The circuit exhibits variability in both space and time by more than fifteen orders of magnitude. We discuss results produced by a new electrical engineering analogue model of the circuit constructed using the PSpice software package. Finally, we consider several interesting new experimental observations relating to the topic.
~http://www.researchgate.net/profile/M_Rycroft/publication/229003754_ACDC_atmospheric_global_electric_circuit_phenomena/file/72e7e521dbfba0d1ea.pdf
‘The global atmospheric electric circuit, solar activity and climate change.’
Abstract:
The study of the global atmospheric electric circuit has advanced dramatically in the past 50 years. Large advances have been made in the areas of lightning and thunderstorm research, as related to the global circuit. We now have satellites looking down on the Earth continuously, supplying information on the temporal and spatial variability of lightning and thunderstorms. Thunderstorms are electric current generators, which drive electric currents up through the conducting atmosphere. They maintain the ionosphere at a potential of ∼+250 kV with respect to the Earth’s surface. The global electric circuit is completed by currents flowing through the fair weather atmosphere, remote from thunderstorms, and by transient currents due to negative cloud-to-ground lightning discharges. The time constant of the circuit, demonstrates that thunderstorms must occur continually to maintain the fair weather electric field. New discoveries have been made in the field of sprites, elves and blue jets, which may have a direct impact on the global circuit. Our knowledge of the global electric circuit modulated by solar effects has improved. Changes to the global circuit are associated with changes of conductivity linked with the time-varying presence of energetic charged particles, and the solar wind may influence the global electric circuit by inferred effects on cloud microphysics, temperature, and dynamics in the troposphere. We now have a better understanding of how the conductivity of the atmosphere is influenced by aerosols, and how this impacts our measurements of the fair-weather global circuit. The global atmospheric electric circuit is also beginning to be recognised by some climate researchers as a useful tool with which to study and monitor the Earth’s changing climate.
~ http://blogs.sch.gr/sachinidi/files/2010/09/The-global-atmospheric-electric-circuit-solar-activity-and-climate-change.pdf
‘Solar and geomagnetic activity, extremely low frequency magnetic and electric fields and human health at the Earth’s surface’
Abstract:
The possibility that conditions on the Sun and in the Earth’s magnetosphere can affect human health at the Earth’s surface has been debated for many decades. This work reviews the research undertaken in the field of heliobiology, focusing on the effect of variations of geomagnetic activity on human cardiovascular health. Data from previous research are analysed for their statistical significance, resulting in support for some studies and the undermining of others. Three conclusions are that geomagnetic effects are more pronounced at higher magnetic latitudes, that extremely high as well as extremely low values of geomagnetic activity seem to have adverse health effects and that a subset of the population (10–15%) is predisposed to adverse health due to geomagnetic variations. The reported health effects of anthropogenic sources of electric and magnetic fields are also briefly discussed, as research performed in this area could help to explain the results from studies into natural electric and magnetic field interactions with the human body. Possible mechanisms by which variations in solar and geophysical parameters could affect human health are discussed and the most likely candidates investigated further. Direct effects of natural ELF electric and magnetic fields appear implausible; a mechanism involving some form of resonant absorption is more likely. The idea that the Schumann resonance signals could be the global environmental signal absorbed by the human body, thereby linking geomagnetic activity and human health is investigated. Suppression of melatonin secreted by the pineal gland, possibly via desynchronised biological rhythms, appears to be a promising contender linking geomagnetic activity and human health. There are indications that calcium ions in cells could play a role in one or more mechanisms. It is found to be unlikely that a single mechanism can explain all of the reported phenomena.
~ http://www.optisan.eu/docs/referenz-umgebungsstrahlung/palmer-2006.pdf
‘An overview of Earth’s global electric circuit and atmospheric conductivity’
~ftp://157.105.11.211/sataraid1/disk1/data2/GC/paper/paper/Rycroft_et_al_2008_An_Overview_of_Earths_Global_Electric_Circuit_and_Atmospheric_Conductivity.pdf
‘Lower ionospheric modification by lightning-EMP: Simulation of the night ionosphere over the United States’
~http://onlinelibrary.wiley.com/store/10.1029/2000GL011951/asset/grl13986.pdf?v=1&t=hvsgo095&s=90d543e3e298045089980b751ceba9be2505e384
‘Electromagnetic Atmosphere-Plasma Coupling: The Global Atmospheric Electric Circuit’
~http://centaur.reading.ac.uk/24952/1/Rycroft%26Harrison_ElectromagneticPlasmaCoupling_SSR_preprint.pdf
‘New model simulations of the global atmospheric electric circuit driven by thunderstorms and electrified shower clouds: The roles of lightning and sprites’
~ftp://157.105.11.211/sataraid1/disk1/data2/GC/paper/paper/Rycroft_et_al_2007_New_model_simulations_of_the_global_atmospheric_electric_circuit_driven_by_thunderstorms_and_electrified_shower_clouds_JASTP.pdf
‘Effects of lightning and sprites on the ionospheric potential, and threshold effects on sprite initiation, obtained using an analog model of the global atmospheric electric circuit’
~http://onlinelibrary.wiley.com/store/10.1029/2009JA014758/asset/jgra20246.pdf?v=1&t=hvt35eap&s=e24ead5c3862f3891760aa9098d96e330056b347
‘Recent advances in global electric circuit coupling between the space environment and the troposphere’
Abstract:
The global atmospheric electric circuit is driven by thunderstorms and electrified rain/shower clouds and is also influenced by energetic charged particles from space. The global circuit maintains the ionosphere as an equipotential at∼+250 kV with respect to the good conducting Earth (both land and oceans). Its “load” is the fair weather atmosphere and semi-fair weather atmosphere at large distances from the disturbed weather “generator” regions. The main solar-terrestrial (or space weather) influence on the global circuit arises from spatially and temporally varying fluxes of galactic cosmic rays (GCRs) and energetic electrons precipitating from the magnetosphere. All components of the circuit exhibit much variability in both space and time. Global circuit variations between solar maximum and solar minimum are considered together with Forbush decrease and solar flare effects. The variability in ion concentration and vertical current flow are considered in terms of radiative effects in the troposphere, through infra-red absorption, and cloud effects, in particular possible cloud microphysical effects from charging at layer cloud edges. The paper identifies future research areas in relation to Task Group 4 of the Climate and Weather of the Sun-Earth System (CAWSES-II) programme.
~ http://www.tau.ac.il/~colin/courses/AtmosElec/Rycroft2012.pdf
HARRISON –
‘The global atmospheric electrical circuit and climate.’
Abstract:
Evidence is emerging for physical links among clouds, global temperatures, the global atmospheric electrical circuit and cosmic ray ionisation. The global circuit extends throughout the atmosphere from the planetary surface to the lower layers of the ionosphere. Cosmic rays are the principal source of atmospheric ions away from the continental boundary layer: the ions formed permit a vertical conduction current to flow in the fair weather part of the global circuit. Through the (inverse) solar modulation of cosmic rays, the resulting columnar ionisation changes may allow the global circuit to convey a solar influence to meteorological phenomena of the lower atmosphere. Electrical effects on non-thunderstorm clouds have been proposed to occur via the ion-assisted formation of ultra-fine aerosol, which can grow to sizes able to act as cloud condensation nuclei, or through the increased ice nucleation capability of charged aerosols. Even small atmospheric electrical modulations on the aerosol size distribution can affect cloud properties and modify the radiative balance of the atmosphere, through changes communicated globally by the atmospheric electrical circuit. Despite a long history of work in related areas of geophysics, the direct and inverse relationships between the global circuit and global climate remain largely quantitatively unexplored. From reviewing atmospheric electrical measurements made over two centuries and possible paleoclimate proxies, global atmospheric electrical circuit variability should be expected on many timescales.
~ http://arxiv.org/pdf/physics/0506077.pdf
‘Cosmic Rays, Clouds, and Climate’
~http://storage.globalcitizen.net/data/topic/knowledge/uploads/20120309132610705.pdf
‘Cosmic Ray Induced Ion Production in the Atmosphere’
~http://www.researchgate.net/profile/Yuri_Stozhkov/publication/225561401_Cosmic_Ray_Induced_Ion_Production_in_the_Atmosphere/file/32bfe511779a25638d.pdf
‘Solar modulation in surface atmospheric electricity’
~http://centaur.reading.ac.uk/5906/1/HarrisonUsoskin2010_postprint.pdf
‘Evidence for solar wind modulation of lightning’
Abstract:
The response of lightning rates over Europe to arrival of high speed solar wind streams at Earth is investigated using a superposed epoch analysis. Fast solar wind stream arrival is determined from modulation of the solar wind V y component, measured by the Advanced Composition Explorer spacecraft. Lightning rate changes around these event times are determined from the very low frequency arrival time difference (ATD) system of the UK Met Office. Arrival of high speed streams at Earth is found to be preceded by a decrease in total solar irradiance and an increase in sunspot number and Mg II emissions. These are consistent with the high speed stream’s source being co-located with an active region appearing on the Eastern solar limb and rotating at the 27 d period of the Sun. Arrival of the high speed stream at Earth also coincides with a small (~1%) but rapid decrease in galactic cosmic ray flux, a moderate (~6%) increase in lower energy solar energetic protons (SEPs), and a substantial, statistically significant increase in lightning rates. These changes persist for around 40 d in all three quantities. The lightning rate increase is corroborated by an increase in the total number of thunder days observed by UK Met stations, again persisting for around 40 d after the arrival of a high speed solar wind stream. This result appears to contradict earlier studies that found an anti-correlation between sunspot number and thunder days over solar cycle timescales. The increase in lightning rates and thunder days that we observe coincides with an increased flux of SEPs which, while not being detected at ground level, nevertheless penetrate the atmosphere to tropospheric altitudes. This effect could be further amplified by an increase in mean lightning stroke intensity that brings more strokes above the detection threshold of the ATD system. In order to remove any potential seasonal bias the analysis was repeated for daily solar wind triggers occurring during the summer months (June to August). Though this reduced the number of solar wind triggers to 32, the response in both lightning and thunder day data remained statistically significant. This modulation of lightning by regular and predictable solar wind events may be beneficial to medium range forecasting of hazardous weather.
~ http://iopscience.iop.org/1748-9326/9/5/055004/pdf/1748-9326_9_5_055004.pdf
‘Cloud base height and cosmic rays’
~http://rspa.royalsocietypublishing.org/content/467/2134/2777.full.pdf
‘Ions in the Terrestrial Atmosphere and Other Solar System Atmospheres’
~ http://link.springer.com/article/10.1007/s11214-008-9356-x
‘Energetic Charged Particles Above Thunderclouds’
Abstract:
The French government has committed to launch the satellite TARANIS to study transient coupling processes between the Earth’s atmosphere and near-Earth space. The prime objective of TARANIS is to detect energetic charged particles and hard radiation emanating from thunderclouds. The British Nobel prize winner C.T.R. Wilson predicted lightning discharges from the top of thunderclouds into space almost a century ago. However, new experiments have only recently confirmed energetic discharge processes which transfer energy from the top of thunderclouds into the upper atmosphere and near-Earth space; they are now denoted as transient luminous events, terrestrial gamma-ray flashes and relativistic electron beams. This meeting report builds on the current state of scientific knowledge on the physics of plasmas in the laboratory and naturally occurring plasmas in the Earth’s atmosphere to propose areas of future research. The report specifically reflects presentations delivered by the members of a novel Franco-British collaboration during a meeting at the French Embassy in London held in November 2011. The scientific subjects of the report tackle ionization processes leading to electrical discharge processes, observations of transient luminous events, electromagnetic emissions, energetic charged particles and their impact on the Earth’s atmosphere. The importance of future research in this area for science and society, and towards spacecraft protection, is emphasized.
~ http://link.springer.com/article/10.1007/s10712-012-9205-z
‘Meteorological effects of the eclipse of 11 August 1999 in cloudy and clear conditions’
~http://www.eumetcal.org/resources/eumetsat_special_images_1/3/Solar_Eclipse_11-Aug-1999/Reports/Paper_Aplin.pdf
‘Multi-station synthesis of early twentieth century surface atmospheric electricity measurements for upper tropospheric properties.’
~ http://www.adv-geosci.net/13/17/2007/adgeo-13-17-2007.pdf
‘Electrical signature in polar night cloud base variations’
~ http://iopscience.iop.org/1748-9326/8/1/015027/pdf/1748-9326_8_1_015027.pdf
~http://iopscience.iop.org/1748-9326/8/1/015027/video/abstract
‘Empirical evidence for a nonlinear effect of galactic cosmic rays on clouds’
Abstract:
Galactic cosmic ray (GCR) changes have been suggested to affect weather and climate, and new evidence is presented here directly linking GCRs with clouds. Clouds increase the diffuse solar radiation, measured continuously at UK surface meteorological sites since 1947. The ratio of diffuse to total solar radiation—the diffuse fraction (DF)—is used to infer cloud, and is compared with the daily mean neutron count rate measured at Climax, Colorado from 1951–2000, which provides a globally representative indicator of cosmic rays. Across the UK, on days of high cosmic ray flux (above 3600×102 neutron counts h−1, which occur 87% of the time on average) compared with low cosmic ray flux, (i) the chance of an overcast day increases by (19±4) %, and (ii) the diffuse fraction increases by (2±0.3) %. During sudden transient reductions in cosmic rays (e.g. Forbush events), simultaneous decreases occur in the diffuse fraction. The diffuse radiation changes are, therefore, unambiguously due to cosmic rays. Although the statistically significant nonlinear cosmic ray effect is small, it will have a considerably larger aggregate effect on longer timescale (e.g. centennial) climate variations when day-to-day variability averages out.
~ http://earthshine.dmi.dk/tellux/HarrisonStephensonGCRClouds.pdf
‘Space weather driven changes in lower atmosphere phenomena’
Abstract:
During a period of heliospheric disturbance in 2007–9 associated with a co-rotating interaction region (CIR), a characteristic periodic variation becomes apparent in neutron monitor data. This variation is phase-locked to periodic heliospheric current sheet crossings. Phase-locked electrical variations are also seen in the terrestrial lower atmosphere in the southern UK, including an increase in the vertical conduction current density of fair weather atmospheric electricity during increases in galactic cosmic ray-induced neutron monitor count rate at the surface and energetic proton count rates measured by geosynchronous spacecraft. At the same time as the conduction current increases, changes in the cloud microphysical properties lead to an increase in the detected height of the cloud base at Lerwick Observatory, Shetland, with associated changes in surface meteorological quantities. As electrification is expected at the base of layer clouds, which can influence droplet properties, these observations of phase-locked thermodynamic, cloud, atmospheric electricity and solar sector changes are not inconsistent with a heliospheric disturbance driving lower troposphere changes.
~ http://centaur.reading.ac.uk/32243/1/pre-print.pdf
‘Atmospheric electricity and cloud microphysics’
~ http://cds.cern.ch/record/557170/files/p75.pdf
‘Atmospheric electricity coupling between earthquake regions and the ionosphere’
~http://centaur.reading.ac.uk/5905/1/HAR_Earthquakes_MS_postprint_(2).pdf
‘Brief Communication: Earthquake–cloud coupling through the global atmospheric electric circuit’
Abstract:
We illustrate how coupling could occur between surface air and clouds via the global electric circuit – through Atmospheric Lithosphere–Ionosphere Charge Exchange (ALICE) processes – in an attempt to develop a physical understanding of the possible relationships between earthquakes and clouds.
~ http://www.nat-hazards-earth-syst-sci.net/14/773/2014/nhess-14-773-2014.pdf
TINSLEY –
‘Correlations of atmospheric dynamics with solar activity evidence for a connection via the solar wind, atmospheric electricity, and cloud microphysics’
Abstract:
We respond to several criticisms of the view that there is a physical linkage between solar activity and the dynamics of the troposphere and lower stratosphere, and we provide further evidence in support of a mechanism for such a linkage involving atmospheric electricity and cloud microphysics. The main criticisms are (1) that the decadal time scale variations in stratified data result from aliasing introduced by the sampling process and are not responses to a decadal time scale physical input; (2) that the observed correlations are due to chance coincidence or an atmospheric periodicity that is not uniquely related to solar variability; and (3) that there are no plausible mechanisms that can amplify one of the weak solar-varying inputs in the region where the correlations are found. We show that the aliasing criticism is inadequate because the real quasi-biennial oscillation departs from an ideal sine wave in a way that reduces aliasing effects to insignificant levels. The nonuniqueness of identification of the 11-year solar cycle as the period of the arctic forcing for the Arctic winter stratospheric temperatures is a problem only for the short 33-year record of polar temperatures; in much longer time series of unstratified climate data the periods of 11 and 22 years are prominent. Highly unique signatures of solar wind forcing of tropospheric dynamics exist on the day-to-day time scale via two independent inputs to atmospheric electricity. These are (1) through changes in tropospheric ion production as a result of solar wind modulation of galactic cosmic rays and (2) through changes in the potential difference between the polar ionospheres and the surface, forced by the solar wind By component. The product of the cosmic ray flux and the ionospheric potential determines the vertical air-earth electrical current. In the presence of clouds of large horizontal extent, this current determines the rate of polarization charging of the clouds via the accumulation of positive electrostatic charges on droplets near cloud tops. The observed correlations, and theoretical and laboratory results for the effects of electrostatic charges on droplets and aerosols on the rates of ice nucleation, are consistent with the postulate that for certain regions and seasons and atmospheric levels the large-scale atmospheric electrical parameters have significant effects on the rates of initial ice nucleation. In such cases the chain of consequences includes changes in the rates of precipitation, net latent heat release, vertical motions, atmospheric vorticity, and ultimately in the general circulation. Much more work is required before the mechanism can be considered to have a secure basis in laboratory experiment and quantitative atmospheric modeling.
~ http://gacc.nifc.gov/sacc/predictive/SOLAR_WEATHER-CLIMATE_STUDIES/GCR%20GEC-Solar%20Wind-Corres%20with%20Atmos%20Dynamics%20Electricity%20cloud%20microphysics%20Tinsley%201993Jun20.pdf
‘The global atmospheric electric circuit and its effects on cloud microphysics’
Abstract:
This review is an overview of progress in understanding the theory and observation of the global atmospheric electric circuit, with the focus on its dc aspects, and its short and long term variability. The effects of the downward ionosphere-earth current density, Jz, on cloud microphysics, with its variability as an explanation for small observed changes in weather and climate, will also be reviewed. The global circuit shows responses to external as well as internal forcing. External forcing arises from changes in the distribution of conductivity due to changes in the cosmic ray flux and other energetic space particle fluxes, and at high magnetic latitudes from solar wind electric fields. Internal forcing arises from changes in the generators and changes in volcanic and anthropogenic aerosols in the troposphere and stratosphere. All these result in spatial and temporal variation in Jz.
Variations in Jz affect the production of space charge in layer clouds, with the charges being transferred to droplets and aerosol particles. New observations and new analyses are consistent with non-negligible effects of the charges on the microphysics of such clouds. Observed effects are small, but of high statistical significance for cloud cover and precipitation changes, with resulting atmospheric temperature, pressure and dynamics changes. These effects are detectable on the day-to-day timescale for repeated Jz changes of order 10%, and are thus second order electrical effects. The implicit first order effects have not, as yet, been incorporated into basic cloud and aerosol physics. Long term (multidecadal through millennial) global circuit changes, due to solar activity modulating the galactic cosmic ray flux, are an order of magnitude greater at high latitudes and in the stratosphere, as can be inferred from geological cosmogenic isotope records. Proxies for climate change in the same stratified depositories show strong correlations of climate with the inferred global circuit variations.
The theory for electrical effects on scavenging of aerosols in clouds is reviewed, with several microphysical processes having consequences for contact ice nucleation; effects on droplet size distributions; precipitation and cloud lifetimes. There are several pathways for resulting macroscopic cloud changes that affect atmospheric circulation; including enhanced ice production and precipitation from clouds in cyclonic storms, with latent heat release affecting cyclone vorticity; and cloud cover changes in layer clouds that affect the atmospheric radiation balance. These macroscopic consequences of global circuit variability affecting aerosols–cloud interactions provide explanations for the many observations of short term and long term changes in clouds and climate that correlate with measured or inferred Jz and cosmic ray flux changes due to external or internal forcing, and lead to predictions of additional effects.
~ http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.322.6222&rep=rep1&type=pdf
‘Influence of Solar Wind on the Global Electric Circuit, and Inferred effects on Cloud Microphysics’
~ http://www.leif.org/EOS/Tin_rev.pdf
‘The Role of the Global Electric Circuit in Solar and Internal Forcing of Clouds and Climate’
~ http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.395.587&rep=rep1&type=pdf
‘Atmospheric Ionization and Clouds as Links Between Solar Activity and Climate’
~ http://www.agu.org/books/gm/v141/141GM22/141GM22.pdf
‘Scavenging in Weakly Electrified Saturated and Subsaturated Clouds, Treating Aerosol Particles and Droplets as Conducting Spheres’
~http://onlinelibrary.wiley.com/store/10.1029/2008JD011527/asset/jgrd15393.pdf?v=1&t=hvsdyyaj&s=8d0fff2e0dbb75826c6bcf9adcdff19369dc844e
‘Initial results of a Global Circuit Model with Variable Stratospheric and Tropospheric Aerosols’
~http://onlinelibrary.wiley.com/store/10.1029/2005JD006988/asset/jgrd12861.pdf?v=1&t=hvsfj2me&s=46614e48c7f1a57f73819d14913c5a6d688bff97
‘Electric Charge Modulation of Aerosol Scavenging in Clouds: Rate Coefficients with Monte-Carlo Simulations of Diffusion’
~http://onlinelibrary.wiley.com/store/10.1029/2010JD014580/asset/jgrd16674.pdf?v=1&t=hvsf0llp&s=ace4dac08da3fc586494577b058ea5e026dfd45f
‘Charge modulation of scavenging in clouds: Extension of Monte Carlo simulations and initial parameterization’
Abstract:
Parameterization has been applied to extended Monte Carlo simulations of the electric charge modulation of aerosol scavenging by droplets, both for particle charges of the same sign as droplets and of opposite sign. Separate parameterizations are given for electro-antiscavenging for small aerosol particles with same-sign charges; electroscavenging for larger particles with same-sign charges; and electroscavenging for opposite-sign particles. A wide range of sizes and charges is treated, together with altitude and humidity variations. The simulations of particle trajectories take Brownian diffusion into account by Monte Carlo perturbations and include the full conducting-sphere electrical force, and phoretic and gravitational forces. For larger particles with larger droplets, the image force causes increases in collision rate coefficients irrespective of the sign of the particle charge, or the amount and sign of the droplet charge, or the degree to which space charge in the cloud is unipolar. Thus, even with little space charge in a cloud, the atmospheric ion production increases the scavenging of larger aerosol particles. With the presence of space charge, the scavenging rate for small particles with high mobility decreases or increases depending on the unipolarity of the space charge. The results are applicable to a wide range of electrical environments associated with clouds and stratified aerosol layers, and are relevant to precipitation and ice-nucleation processes and cloud albedo effects.
~ http://onlinelibrary.wiley.com/doi/10.1002/jgrd.50618/abstract
‘A working hypothesis for connections between electrically-induced changes in cloud microphysics and storm vorticity, with possible effects on circulation’
Abstract:
This paper outlines, and explores the uncertainties in, hypothesized connections between a series of processes that could explain two long-standing puzzles; those of (1) the observed winter storm vorticity responses to atmospheric energy inputs that change the ionosphere–earth current density, Jz, that appear to involve storm invigoration, and (2) changes in anti-cyclonic blocking and circulation that include the observed colder winters in Great Britain and western Europe at solar minima, and especially at extended solar minima. A working hypothesis for the mechanism responsible for (1) is that the flow of Jz through conductivity gradients, as in stratified cloud layers and fog, especially with sea-salt aerosol haze over the high latitude winter oceans, deposits electric changes on droplets and aerosol particles; most importantly on cloud condensation nuclei (CCN). These electric charges modulate scavenging of the particles in clouds and haze layers, increasing the concentration of small CCN and decreasing the concentration of large CCN. When further cloud formation occurs there is increased concentration of small droplets and decreased concentration of large ones, reducing coalescence and the production of rain. Thus updrafts carry more liquid water above the freezing level, and there the increased production of ice releases more latent heat and invigorates the updraft (the Rosenfeld mechanism), leading to increased vorticity. Here we explore the major uncertainties for the reality of the above chain of physical processes. A consequence of cumulative cyclonic vorticity increases is increases in downstream anti-cyclonic blocking. A further working hypothesis for (2) is that the invigoration may be large enough to contribute to the observed increases in blocking in winters at solar minima (high Jz) in the North Atlantic, that result in colder winters in the UK and northern Europe.
~http://www.sciencedirect.com/science/article/pii/S0273117712002517
‘Global electric circuit modulation of winter cyclone vorticity in the northern high latitudes’
Abstract:
Small changes in extended winter (November–March) 500 hPa vorticity area index (VAI) values for the 60–80°N latitude band are shown to be positively correlated with changes in a proxy for the high latitude ionosphere-to-surface current density .
The proxy was obtained from low latitude values, measured at Mauna Loa Observatory (MLO) during the years 1960–1961 and 1977–1982, which were taken as proportional to the global ionospheric potential . Such MLO values may also serve as proxies for high latitude , provided that they are not used during Forbush decreases or during periods of high stratospheric aerosol loading. The MLO data were of sufficient quantity and quality to obtain high latitude proxies for five northern hemisphere winters. These proxies were used in linear regressions with lagged values of anomalies in the VAI (with lags extending from −150 to +150 days). For the regression analysis using VAI values from the four 1977–1982 winters, the largest value occurred for a lag of +2 days, and the corresponding regression coefficient was the second largest in magnitude for the 301 day interval. An ANOVA test showed this result to have a statistical significance of greater than 95%. For the regression analysis using data from only the 1960–1961 winter, both the maximum slope and value occurred for a lag of −3 days. However, the autocorrelation of the VAI has a width of ∼15 days, and the noise associated with the small number of data points for 1960–1961 suggests that the maxima were displaced to negative lags by noise. The overall results are consistent with Tinsley’s hypothesis that higher values enhance the vorticities of relatively intense winter cyclones when latent heat is important for their development. Electric charge deposited in clouds by modulates the scavenging rates for both cloud condensation nuclei and ice-forming nuclei. The hypothesis is that these modulate the updraft vigor by the Rosenfeld mechanism, thus increasing the cyclonic vorticity.
~http://www.sciencedirect.com/science/article/pii/S0273117712001688
‘Atmospheric Circuit Influences on Ground Level Pressure in the Antarctic and Arctic’
~ftp://157.105.11.211/sataraid1/disk1/data2/GC/paper/paper/Buns_et_al_Atmospheric_circuit_influences_on_ground-level_pressure_in_the_Antarctic_and_Arctic_JGR_2008.pdf
Abstract:
The goal of this article is to investigate the influence of solar activity on thunderstorm activity in Brazil. For this purpose, thunder day data from seven cities in Brazil from 1951 to 2009 are analyzed with the wavelet method for the first time. To identify the 11-year solar cycle in thunder day data, a new quantity is defined. It is named TD1 and represents the power in 1-year in a wavelet spectrum of monthly thunder day data. The wavelet analysis of TD1 values shows more clear the 11-year periodicity than when it is applied directly to annual thunder day data, as it has been normally investigated in the literature. The use of this new quantity is shown to enhance the capability to identify the 11-year periodicity in thunderstorm data. Wavelet analysis of TD1 indicates that six out seven cities investigated exhibit periodicities near 11 years, three of them significant at a 1% significance level (p<0.01). Furthermore, wavelet coherence analysis demonstrated that the 11-year periodicity of TD1 and solar activity are correlated with an anti-phase behavior, three of them (the same cities with periodicities with 1% significance level) significant at a 5% significance level (p<0.05). The results are compared with those obtained from the same data set but using annual thunder day data. Finally, the results are compared with previous results obtained for other regions and a discussion about possible mechanisms to explain them is done. The existence of periodicities around 11 years in six out of seven cities and their anti-phase behavior with respect to 11-year solar cycle suggest a global mechanism probably related to a solar magnetic shielding effect acting on galactic cosmic rays as an explanation for the relationship of thunderstorm and solar activity, although more studies are necessary to clarify its physical origin. ~http://www.sciencedirect.com/science/article/pii/S1364682613000862