Commutator (electric)

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Commutator_(electric) 

Commutator in a universal motor from a vacuum cleaner. Parts: (A) commutator, (B) brush, (C) rotor (armature) windings, (D) stator (field) windings, (E) brush guides, (F) electrical connections.

A commutator is a rotary electrical switch in certain types of electric motors and electrical generators that periodically reverses the current direction between the rotor and the external circuit. It consists of a cylinder composed of multiple metal contact segments on the rotating armature of the machine. Two or more electrical contacts called "brushes" made of a soft conductive material like carbon press against the commutator, making sliding contact with successive segments of the commutator as it rotates. The windings (coils of wire) on the armature are connected to the commutator segments.

Commutators are used in direct current (DC) machines: dynamos (DC generators) and many DC motors as well as universal motors. In a motor the commutator applies electric current to the windings. By reversing the current direction in the rotating windings each half turn, a steady rotating force (torque) is produced. In a generator the commutator picks off the current generated in the windings, reversing the direction of the current with each half turn, serving as a mechanical rectifier to convert the alternating current from the windings to unidirectional direct current in the external load circuit. The first direct current commutator-type machine, the dynamo, was built by Hippolyte Pixii in 1832, based on a suggestion by André-Marie Ampère.

Commutators are relatively inefficient, and also require periodic maintenance such as brush replacement. Therefore, commutated machines are declining in use, being replaced by alternating current (AC) machines, and in recent years by brushless DC motors which use semiconductor switches.

Principle of operation

A commutator consists of a set of contact bars fixed to the rotating shaft of a machine, and connected to the armature windings. As the shaft rotates, the commutator reverses the flow of current in a winding. For a single armature winding, when the shaft has made one-half complete turn, the winding is now connected so that current flows through it in the opposite of the initial direction. In a motor, the armature current causes the fixed magnetic field to exert a rotational force, or a torque, on the winding to make it turn. In a generator, the mechanical torque applied to the shaft maintains the motion of the armature winding through the stationary magnetic field, inducing a current in the winding. In both the motor and generator case, the commutator periodically reverses the direction of current flow through the winding so that current flow in the circuit external to the machine continues in only one direction.

Simplest practical commutator

Practical commutators have at least three contact segments, to prevent a "dead" spot where two brushes simultaneously bridge only two commutator segments. Brushes are made wider than the insulated gap, to ensure that brushes are always in contact with an armature coil. For commutators with at least three segments, although the rotor can potentially stop in a position where two commutator segments touch one brush, this only de-energizes one of the rotor arms while the others will still function correctly. With the remaining rotor arms, a motor can produce sufficient torque to begin spinning the rotor, and a generator can provide useful power to an external circuit.

Ring/segment construction

Cross-section of a commutator that can be disassembled for repair.

A commutator consists of a set of copper segments, fixed around the part of the circumference of the rotating machine, or the rotor, and a set of spring-loaded brushes fixed to the stationary frame of the machine. Two or more fixed brushes connect to the external circuit, either a source of current for a motor or a load for a generator.

Commutator segments are connected to the coils of the armature, with the number of coils (and commutator segments) depending on the speed and voltage of the machine. Large motors may have hundreds of segments. Each conducting segment of the commutator is insulated from adjacent segments. Mica was used on early machines and is still used on large machines. Many other insulating materials are used to insulate smaller machines; plastics allow quick manufacture of an insulator, for example. The segments are held onto the shaft using a dovetail shape on the edges or underside of each segment. Insulating wedges around the perimeter of each segment are pressed so that the commutator maintains its mechanical stability throughout its normal operating range.

In small appliance and tool motors the segments are typically crimped permanently in place and cannot be removed. When the motor fails it is discarded and replaced. On large industrial machines (say, from several kilowatts to thousands of kilowatts in rating) it is economical to replace individual damaged segments, and so the end-wedge can be unscrewed and individual segments removed and replaced.

Replacing the copper and mica segments is commonly referred to as "refilling". Refillable dovetailed commutators are the most common construction of larger industrial type commutators, but refillable commutators may also be constructed using external bands made of fiberglass (glass banded construction) or forged steel rings (external steel shrink ring type construction and internal steel shrink ring type construction).

Disposable, molded type commutators commonly found in smaller DC motors are becoming increasingly more common in larger electric motors. Molded type commutators are not repairable and must be replaced if damaged.

In addition to the commonly used heat, torque, and tonnage methods of seasoning commutators, some high performance commutator applications require a more expensive, specific "spin seasoning" process or over-speed spin-testing to guarantee stability of the individual segments and prevent premature wear of the carbon brushes. Such requirements are common with traction, military, aerospace, nuclear, mining, and high speed applications where clamping failure and segment or insulation protrusion can lead to serious negative consequences.

Friction between the segments and the brushes eventually causes wear to both surfaces. Carbon brushes, being made of a softer material, wear faster and may be designed to be replaced easily without dismantling the machine. Older copper brushes caused more wear to the commutator, causing deep grooving and notching of the surface over time.

The commutator on small motors (say, less than a kilowatt rating) is not designed to be repaired through the life of the device. On large industrial equipment, the commutator may be re-surfaced with abrasives, or the rotor may be removed from the frame, mounted in a large metal lathe, and the commutator resurfaced by cutting it down to a smaller diameter. The largest of equipment can include a lathe turning attachment directly over the commutator.

A tiny 5-segment commutator less than 2 mm in diameter, on a direct-current motor in a toy radio control ZipZaps car.

Brush construction

Various types of copper and carbon brushes.

Early machines used brushes made from strands of copper wire to contact the surface of the commutator. However, these hard metal brushes tended to scratch and groove the smooth commutator segments, eventually requiring resurfacing of the commutator. As the copper brushes wore away, the dust and pieces of the brush could wedge between commutator segments, shorting them and reducing the efficiency of the device. Fine copper wire mesh or gauze provided better surface contact with less segment wear, but gauze brushes were more expensive than strip or wire copper brushes.

Modern rotating machines with commutators almost exclusively use carbon brushes, which may have copper powder mixed in to improve conductivity. Metallic copper brushes can be found in toy or very small motors, such as the one illustrated above, and some motors which only operate very intermittently, such as automotive starter motors.

Motors and generators suffer from a phenomenon known as 'armature reaction', one of the effects of which is to change the position at which the current reversal through the windings should ideally take place as the loading varies. Early machines had the brushes mounted on a ring that was provided with a handle. During operation, it was necessary to adjust the position of the brush ring to adjust the commutation to minimise the sparking at the brushes. This process was known as 'rocking the brushes'.

Various developments took place to automate the process of adjusting the commutation and minimizing the sparking at the brushes. One of these was the development of 'high resistance brushes', or brushes made from a mixture of copper powder and carbon. Although described as high resistance brushes, the resistance of such a brush was of the order of milliohms, the exact value dependent on the size and function of the machine. Also, the high resistance brush was not constructed like a brush but in the form of a carbon block with a curved face to match the shape of the commutator.

The high resistance or carbon brush is made large enough that it is significantly wider than the insulating segment that it spans (and on large machines may often span two insulating segments). The result of this is that as the commutator segment passes from under the brush, the current passing to it ramps down more smoothly than had been the case with pure copper brushes where the contact broke suddenly. Similarly the segment coming into contact with the brush has a similar ramping up of the current. Thus, although the current passing through the brush was more or less constant, the instantaneous current passing to the two commutator segments was proportional to the relative area in contact with the brush.

The introduction of the carbon brush had convenient side effects. Carbon brushes tend to wear more evenly than copper brushes, and the soft carbon causes far less damage to the commutator segments. There is less sparking with carbon as compared to copper, and as the carbon wears away, the higher resistance of carbon results in fewer problems from the dust collecting on the commutator segments.

The ratio of copper to carbon can be changed for a particular purpose. Brushes with higher copper content perform better with very low voltages and high current, while brushes with a higher carbon content are better for high voltage and low current. High copper content brushes typically carry 150 to 200 amperes per square inch of contact surface, while higher carbon content only carries 40 to 70 amperes per square inch. The higher resistance of carbon also results in a greater voltage drop of 0.8 to 1.0 volts per contact, or 1.6 to 2.0 volts across the commutator.

Brush holders

Compound carbon brush holder, with individual clamps and tension adjustments for each block of carbon.

A spring is typically used with the brush, to maintain constant contact with the commutator. As the brush and commutator wear down, the spring steadily pushes the brush downwards towards the commutator. Eventually the brush wears small and thin enough that steady contact is no longer possible or it is no longer securely held in the brush holder, and so the brush must be replaced.

It is common for a flexible power cable to be directly attached to the brush, because current flowing through the support spring would cause heating, which may lead to a loss of metal temper and a loss of the spring tension.

When a commutated motor or generator uses more power than a single brush is capable of conducting, an assembly of several brush holders is mounted in parallel across the surface of the very large commutator. This parallel holder distributes current evenly across all the brushes, and permits a careful operator to remove a bad brush and replace it with a new one, even as the machine continues to spin fully powered and under load.

High power, high current commutated equipment is now uncommon, due to the less complex design of alternating current generators that permits a low current, high voltage spinning field coil to energize high current fixed-position stator coils. This permits the use of very small singular brushes in the alternator design. In this instance, the rotating contacts are continuous rings, called slip rings, and no switching happens.

Modern devices using carbon brushes usually have a maintenance-free design that requires no adjustment throughout the life of the device, using a fixed-position brush holder slot and a combined brush-spring-cable assembly that fits into the slot. The worn brush is pulled out and a new brush inserted.

Brush contact angle

Different types of brushes have different brush contact angles

 

Commutator and brush assembly of a traction motor; the copper bars can be seen with lighter insulation strips between the bars. Each dark grey carbon brush has a short flexible copper jumper lead attached. Parts of the motor field winding, in red, can be seen to the right of the commutator.

The different brush types make contact with the commutator in different ways. Because copper brushes have the same hardness as the commutator segments, the rotor cannot be spun backwards against the ends of copper brushes without the copper digging into the segments and causing severe damage. Consequently, strip/laminate copper brushes only make tangential contact with the commutator, while copper mesh and wire brushes use an inclined contact angle touching their edge across the segments of a commutator that can spin in only one direction.

The softness of carbon brushes permits direct radial end-contact with the commutator without damage to the segments, permitting easy reversal of rotor direction, without the need to reorient the brush holders for operation in the opposite direction. Although never reversed, common appliance motors that use wound rotors, commutators and brushes have radial-contact brushes. In the case of a reaction-type carbon brush holder, carbon brushes may be reversely inclined with the commutator so that the commutator tends to push against the carbon for firm contact.

The commutating plane

Commutating plane definitions.

The contact point where a brush touches the commutator is referred to as the commutating plane. To conduct sufficient current to or from the commutator, the brush contact area is not a thin line but instead a rectangular patch across the segments. Typically the brush is wide enough to span 2.5 commutator segments. This means that two adjacent segments are electrically connected by the brush when it contacts both.

Rotation of brushes for stator field distortion

Centered position of the commutating plane if there were no field distortion effects.

Most introductions to motor and generator design start with a simple two-pole device with the brushes arranged at a perfect 90-degree angle from the field. This ideal is useful as a starting point for understanding how the fields interact but it is not how a motor or generator functions in actual practice.

On the left is an exaggerated example of how the field is distorted by the rotor. On the right, iron filings show the distorted field across the rotor.

In a real motor or generator, the field around the rotor is never perfectly uniform. Instead, the rotation of the rotor induces field effects which drag and distort the magnetic lines of the outer non-rotating stator.

Actual position of the commutating plane to compensate for field distortion.

The faster the rotor spins, the further this degree of field distortion. Because a motor or generator operates most efficiently with the rotor field at right angles to the stator field, it is necessary to either retard or advance the brush position to put the rotor's field into the correct position to be at a right angle to the distorted field.

These field effects are reversed when the direction of spin is reversed. It is therefore difficult to build an efficient reversible commutated dynamo, since for highest field strength it is necessary to move the brushes to the opposite side of the normal neutral plane. These effects can be mitigated by a compensation winding in the face of the field pole that carries armature current.

The effect can be considered to be analogous to timing advance in an internal combustion engine. Generally a dynamo that has been designed to run at a certain fixed speed will have its brushes permanently fixed to align the field for highest efficiency at that speed.

Further compensation for self-induction

Brush advance for Self-Induction.

Self-induction – The magnetic fields in each coil of wire join and compound together to create a magnetic field that resists changes in the current, which can be likened to the current having inertia.

In the coils of the rotor, even after the brush has been reached, currents tend to continue to flow for a brief moment, resulting in a wasted energy as heat due to the brush spanning across several commutator segments and the current short-circuiting across the segments.

Spurious resistance is an apparent increase in the resistance in the armature winding, which is proportional to the speed of the armature, and is due to the lagging of the current.

To minimize sparking at the brushes due to this short-circuiting, the brushes are advanced a few degrees further yet, beyond the advance for field distortions. This moves the rotor winding undergoing commutation slightly forward into the stator field which has magnetic lines in the opposite direction and which oppose the field in the stator. This opposing field helps to reverse the lagging self-inducting current in the stator.

So even for a rotor which is at rest and initially requires no compensation for spinning field distortions, the brushes should still be advanced beyond the perfect 90-degree angle as taught in so many beginners textbooks, to compensate for self-induction.

Use of interpoles to correct field distortions

Modern motor and generator devices with commutators are able to counteract armature reaction through the use of interpoles, which are small field coils and pole pieces positioned approximately halfway between the primary poles of the stator.

By applying a dynamic varying field to the interpoles as the load, RPM, or direction of rotation of the device changes, it is possible to balance out field distortions from armature reaction so that the brush position can remain fixed and sparking across the segments is minimized.

Limitations and alternatives

Low voltage dynamo from late 1800s for electroplating. The resistance of the commutator contacts causes inefficiency in low voltage, high current machines like this, requiring a huge elaborate commutator. This machine generated 7 volts at 310 amps.

Although direct current motors and dynamos once dominated industry, the disadvantages of the commutator have caused a decline in the use of commutated machines in the last century. These disadvantages are:

• The sliding friction between the brushes and commutator consumes power, which can be significant in a low power machine.
• Due to friction, the brushes and copper commutator segments wear down, creating dust. In small consumer products such as power tools and appliances the brushes may last as long as the product, but larger machines require regular replacement of brushes and occasional resurfacing of the commutator. So commutated machines are not used in low particulate or sealed applications or in equipment that must operate for long periods without maintenance.
• The resistance of the sliding contact between brush and commutator causes a voltage drop called the "brush drop". This may be several volts, so it can cause large power losses in low voltage, high current machines. Alternating current motors, which do not use commutators, are much more efficient.
• There is a limit to the maximum current density and voltage which can be switched with a commutator. Very large direct current machines, say, more than several megawatts rating, cannot be built with commutators. The largest motors and generators are all alternating-current machines.
• The switching action of the commutator causes sparking at the contacts, posing a fire hazard in explosive atmospheres, and generating electromagnetic interference.

With the wide availability of alternating current, DC motors have been replaced by more efficient AC synchronous or induction motors. In recent years, with the widespread availability of power semiconductors, in many remaining applications commutated DC motors have been replaced with "brushless direct current motors". These don't have a commutator; instead the direction of the current is switched electronically. A sensor keeps track of the rotor position and semiconductor switches such as transistors reverse the current. Operating life of these machines is much longer, limited mainly by bearing wear.

Repulsion induction motors

See also: Repulsion motor

These are single-phase AC-only motors with higher starting torque than could be obtained with split-phase starting windings, before high-capacitance (non-polar, relatively high-current electrolytic) starting capacitors became practical. They have a conventional wound stator as with any induction motor, but the wire-wound rotor is much like that with a conventional commutator. Brushes opposite each other are connected to each other (not to an external circuit), and transformer action induces currents into the rotor that develop torque by repulsion.

One variety, notable for having an adjustable speed, runs continuously with brushes in contact, while another uses repulsion only for high starting torque and in some cases lifts the brushes once the motor is running fast enough. In the latter case, all commutator segments are connected together as well, before the motor attains running speed.

Once at speed, the rotor windings become functionally equivalent to the squirrel-cage structure of a conventional induction motor, and the motor runs as such.

Laboratory commutators

Commutators were used as simple forward-off-reverse switches for electrical experiments in physics laboratories. There are two well-known historical types:

Ruhmkorff commutator

This is similar in design to the commutators used in motors and dynamos. It was usually constructed of brass and ivory (later ebonite).

Pohl commutator

This consisted of a block of wood or ebonite with four wells, containing mercury, which were cross-connected by copper wires. The output was taken from a pair of curved copper wires which were moved to dip into one or other pair of mercury wells. Instead of mercury, ionic liquids or other liquid metals could be used.

Environmental politics

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Environmental_politics

Environmental politics designate both the politics about the environment (see also environmental policy) and an academic field of study focused on three core components:

• The study of political theories and ideas related to the environment;
• The examination of the environmental stances of both mainstream political parties and environmental social movements; and
• The analysis of public policymaking and implementation affecting the environment, at multiple geo-political levels.

Neil Carter, in his foundational text Politics of the Environment (2009), suggests that environmental politics is distinct in at least two ways: first, "it has a primary concern with the relationship between human society and the natural world" (page 3); and second, "unlike most other single issues, it comes replete with its own ideology and political movement" (page 5, drawing on Michael Jacobs, ed., Greening the Millenium?, 1997).

Further, he distinguishes between modern and earlier forms of environmental politics, in particular conservationism and preservationism. Contemporary environmental politics "was driven by the idea of a global ecological crisis that threatened the very existence of humanity." And "modern environmentalism was a political and activist mass movement which demanded a radical transformation in the values and structures of society."

Environmental concerns were rooted in the vast social changes that took place in the United States after World War II. Although environmentalism can be identified in earlier years, only after the war did it become widely shared social priority. This began with outdoor recreation in the 1950s, extended into the wider field of the protection of natural environments, and then became infused with attempts to cope with air and water pollution and still later with toxic chemical pollutants. After World War II, environmental politics became a major public concern. The development of environmentalism in the United Kingdom emerged in this period following the great London smog of 1952 and the Torrey Canyon oil spill of 1967. This is reflected by the emergence of Green politics in the Western world beginning in the 1970s.

Democratic challenges

The roles of democracy and democratic institutions in advancing environmental policy and, in particular, climate policy are mixed, as evidenced by the variation in the environmental progress of different democratic governments. From a theoretical perspective, democratic procedures can effect meaningful reform if public support for these reforms exists, especially when compared with autocratic regimes, as the set of incentives for policymakers to legislate toward these ends in a system deriving legitimacy from the consent of the governed is substantive; for instance, given political responsiveness as a result of electoral accountability, policymakers in democratic governments have reason to consider a wide view of the public interest that incorporates the varied positions of their constituents and work to efficiently create change. On such a view, democracies will likely consider the consequential impacts to most, if not all constituents, caused by climate change. Factors like regime stability and ruler or governing official interests, too, seem better aligned for progress in a democracy; civil unrest is less likely in a state perceived as legitimate, as is graft, both of which appear likely to inhibit climate action.

In contrast, empirical evidence does show inconsistencies in the ways in which democracies address environmental problems. Though the reason for this variation is largely unclear, a number of features of democratic state organization appear to contribute to observed failures to act on climate change, among other environmental issues. Leaders may, in practice, not be motivated by a theoretical public good, but instead expend resources on resolving those policy challenges which are most visible to their electorate. Given the largely intangible nature of climate change as a problem – one that is gradual, invisible, and global – the political opportunity cost of focusing on this challenge or other less visible environmental issues may be high for electorally accountable democratic leaders.

Economic interests and outside influences may also limit the ability of democratic actors to drive meaningful environmental change. In developed democracies, businesses and other groups with economic motivations often hold considerable lobbying power and, therefore, have the ability to forestall climate or environmental progress, which are often unaligned with these groups' financial interests. In developing democracies, environmental reforms are often seen as lesser priorities, given the need for addressing more proximate public concerns, including poverty, infrastructure, and general economic development. Financial incentive can also play a role in preventing the passage of environmental policy outside of the legal realm; some evidence suggests that corruption, present in some form in a number of democratic institutions globally, erodes regulatory ability and public trust in state institutions, reducing the ability of democracies to effectively mitigate carbon emissions and other sources of pollution.

In addition, the problem of popular disinterest in advancing environmental policy presents challenges for the prospects of democratic institutions' ability to drive environmental progress. Despite growing public understanding of the threat posed by climate change, the last decade has seen considerable opposition to pro-environmental policies across broad coalitions and around the globe. Populist movements in Western democracies over the last several years, in particular, have taken positions that actively oppose such policies, and analyses of deliberative modes of participatory democracy have shown results that mirror the interests of those participating and do not necessarily tend towards a more favorable view of environmental or climate action. As redress to these potential shortcomings, means of reforming democratic processes, both theoretical and pragmatic, to correct for what may be short-sighted political interests have been suggested, though these reforms may reduce democratic choice or participation.

Questions of environmental justice, too, may be unanswered by democratic decision-making processes. Not only are those minority groups without meaningful representation in either single-member districts or majority-rule electorates disadvantaged in the realm of political interests, but these same groups are often those most impacted by the effects of climate change and other environmental problems. In addition, recent literature around non-human representation has investigated the ways in which the interests of affected conscious agents, which are definitionally uninvolved in the political decisions of human society, are consistently underrepresented; solutions accounting for this disparity often appeal to reforms that would reduce democratic choice from a traditional perspective, including by giving biological experts greater say in policymaking, though even their ability to determine the interests of non-humans is uncertain. On a global scale, those most impacted by the effects of climate change may have little say in determining policies that would curb emissions or otherwise work to adapt to climate outcomes. Not only do individuals only have the ability to determine climate policy in their own state, but those states that emit the least atmospheric carbon are often most vulnerable to the impacts of climate change, while those that emit the most are often least vulnerable, a discrepancy unaccounted for by democratic processes.

Climate change is slow relative to political cycles of leadership in electoral democracies, which impedes responses by politicians who are elected and re-elected on much shorter timescales.

In the United States, although "environmentalism" was once considered a White phenomenon, scholars have identified "pro-environment positions among Latino, African-American, and non-Hispanic white respondents," with growing environmental concern especially among Latinos. Other scholars have similarly noted that Asian Americans are strongly pro-environmental, with some variation among ethnic subgroups.

Effectively responding to global warming necessitates some form of international environmental governance to achieve shared targets related to energy consumption and environmental usage. Climate change complicates political ideology and practice, affecting conceptions of responsibility for future societies as well as economic systems. Material inequality between nations make technological solutions insufficient for climate change mitigation. Rather, political solutions can navigate the particularities of various facets of environmental crisis. Climate change mitigation strategies can be at odds with democratic priorities of prosperity, progress, and state sovereignty, and instead underscore a collective relationship with the environment.

The international political community is presently based on liberal principles that prioritize individual freedoms and capitalist systems that make quick and ambitious climate responses difficult. Interest-group liberalism is guided by individual human priorities. Groups unable to voice their self-interest, such as minorities without suffrage, or non-humans, are not included in the political compromise. Addressing environmental crises can be impeded when citizens of liberal democracies do not see environmental problems as impacting their lives, or when they lack the education to evaluate the importance of the problem. The human benefits from environmental exploitation and protection compete. Considering the implications of ecological degradation for future human generations can give environmental concerns a basis in anthropocentric liberal democratic politics.

William Ophuls posits that liberal democracies are unfit to address environmental problems, and that the prioritization of these challenges would involve a transition to more authoritarian forms of government. Others counter this by pointing to the past successes of environmental reform movements to improve water and air quality in liberal societies. In practice, environmentalism can improve democracy rather than necessitate its end, by expanding democratic participation and promoting political innovations.

The tensions between liberal democracy and environmental goals raise questions about the possible limitations of democracy (or at least democracy as we know it): in its responsiveness to subtle but large-scale problems, its ability to work from a holistic societal perspective, its aptness in coping with environmental crisis relative to other forms of government. Democracies do not have the provisions to make environmental reforms that are not mandated by voters, and many voters lack incentives or desire to demand policies that could compromise immediate prosperity. The question arises as to whether the foundation of politics is morality or practicality. A scheme that conceives of and values the environment beyond its human utility, an environmental ethics, could be crucial for democracies to respond to climate change.

Alternative forms of democracy for environmental policy

In political theory, deliberative democracy has been discussed as a political model more compatible with environmental goals. Deliberative democracy is a system in which informed political equals weigh values, information, and expertise, and debate priorities to make decisions, as opposed to a democracy based on interest aggregation. This definition of democracy emphasizes informed discussion among citizens in the decision making process, and encourages decisions to benefit the common good rather than individual interests. Amy Gutmann and Dennis Thompson claimed that reason prevails over self-interest in deliberative democracy, making it a more just system. The broad perspective that this discursive model encourages could lead to a stronger engagement with environmental concerns. When compared to non-democracies, democracies are in fact more cooperative in climate change policy creation, but not necessarily on the outcome and effects of these policies.

This can be explained more exhaustively with the concept of grass-roots democracy. Grass-roots democracy is an approach in which ordinary citizens are in charge of politics, in opposition to ‘larger organizations and wealthy individuals with concentrated vested interests in particular policies’. Green parties were once dedicated to offer a project valuing the ideology of grass-roots democracy. However, according to Ostrogorski and Michels, all parties follow inevitably a similar path towards concentration of power and oligarchy. Green parties thus follow different principles nowadays.

In political theory, the lottery system is a democratic design that allows governments to address problems with future, rather than immediate, impacts. Deliberative bodies composed of randomly selected representatives can draft environmental policies that have short-term costs without considering the political consequences for re-election.

New materialism and environmental justice

New materialism is a strain of thought in philosophy and the social sciences that conceives of all material as having life or agency. It criticizes frameworks of justice that center on human attributes like consciousness as insufficient for modern ethical problems that concern the natural environment. It is a post-humanist consideration of all matter that rejects arguments of utility that privilege humans. This politically relevant social theory combats inequality beyond the interpersonal plane. People are ethically responsible for one another, and for the physical spaces they navigate, including animal and plant life, and the inanimate matter that sustains it, like soil. New materialism encourages political action according to this world vision, even if it is incompatible with economic growth.

Jane Bennett uses the term "vital materialism" in her book Vibrant Matter: A Political Ecology of Things. She develops the concept of materialism with the aim of providing a stronger basis in political theory for environmental politics.

New materialists have invoked Derrida and other historical thinkers to trace the emergence of their philosophy and to justify their environmental claims:

"No justice ... seems possible or thinkable without the principle of some responsibility, beyond all living present, within that which disjoins the living present, before the ghosts of those who are not yet born or who are already dead [...]. Without this non-contemporaneity with itself of the living present ... without this responsibility and this respect for justice concerning those who are not there, of those who are no longer or who are not yet present and living, what sense would there be to ask the question 'where?' 'where tomorrow?' 'whither?'"

All material, living and dead, is interrelated in "the mesh" as described by Timothy Morton. As all matter is interdependent, humans have obligations to all parts of the material world, including those that are unfamiliar.

New materialism is related to a shift from the view of the environment as a form of capital to a form of labor (see Ecosystem services).

Emerging nations

Brazil, Russia, India, and China (known as the "BRIC" nations) are rapidly industrializing, and are increasingly responsible for global carbon emissions and the associated climate change. Other forms of environmental degradation have also accompanied the economic growth in these nations. Environmental degradation tends to motivate action more than the threat of global warming does, since air and water pollution cause immediate health problems, and because pollutants can damage natural resources, hampering economic potential.

The Kuznets curve is a hypothetical curve representing the trajectory of environmental degradation in developing nations as a function of per capita income.

With rising incomes, environmental degradation tends to decrease in industrializing nations, as depicted in the Environmental Kuznets Curve (described in a section of the Kuznets Curve article). Citizens demand better air and water quality, and technology becomes more efficient and clean when incomes increase. The level of income per capita needed to reverse the trend of environmental degradation in industrializing nations varies with the environmental impact indicator. More developed nations can facilitate eco-friendly transitions in emerging economies by investing in the development of clean technologies.

Laws implemented in response to environmental concerns vary by nation (see List of environmental laws by country).

China

China's environmental ills include acid rain, severe smog, and a reliance on coal-burning for energy. China has instated environmental policies since the 1970s, and has one of the most extensive environmental conservation programs on paper. However, regulation and enforcement by the central government in Beijing are weak, so solutions are decentralized. Wealthier provinces are far more effective in their preservation and sustainable development efforts than poorer regions. China therefore provides an example of the consequences of environmental damage falling disproportionately on the poor. NGOs, the media, and the international community have all contributed to China's response to environmental problems.

For history, laws, and policies, see Environmental policy in China.

India

In 1976, the Constitution of India was amended to reflect environmental priorities, motivated in part by the potential threat of natural resource depletion to economic growth:

"The State shall endeavour to protect and improve the environment and to safeguard the forests and wildlife." (Art. 48A)

"It shall be the duty of every citizen of India [...] to protect and improve the natural environment including forests, lakes, rivers and wildlife, and to have compassion for living creatures." (Art. 51A)

However, in India, as in China, the implementation of written environmental policies, laws, and amendments has proven challenging. Official legislation by the central government (see a partial list at Environmental policy of the Government of India) is often more symbolic than practical. The Ministry of Environment and Forests was established in 1985, but corruption within bureaucratic agencies, namely the influence of wealthy industry leaders, limited any attempts at enforcement of the policies put in place.

Journals

Scholarly journals representing this field of study include:

• Environmental Politics
• Global Environmental Politics
• International Environmental Agreements

Storm chasing

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Storm_chasing 

Photos from National Severe Storms Laboratory (NSSL) in Norman, Oklahoma show staff and instrument chasing tornadoes during the first VORTEX project from 1994 to 1995. The first photo was in Graham, Texas, and the second southeast of Shamrock, Texas.

 

NSSL vehicles on the first VORTEX project (which operated in the seasons of 1994 – 1995), equipped with surface measurement equipment.

Storm chasing is broadly defined as the deliberate pursuit of any severe weather phenomenon, regardless of motive, but most commonly for curiosity, adventure, scientific investigation, or for news or media coverage. A person who chases storms is known as a storm chaser or simply a chaser.

While witnessing a tornado is the single biggest objective for most chasers, many chase thunderstorms and delight in viewing cumulonimbus and related cloud structures, watching a barrage of hail and lightning, and seeing what skyscapes unfold. A smaller number of storm chasers attempt to intercept tropical cyclones and waterspouts.

Nature of and motivations for chasing

Storm chasing is chiefly a recreational endeavor, with chasers usually giving their motives as photographing or video recording a storm, or for various personal reasons. These can include the beauty of the views afforded by the sky and land, the mystery of not knowing precisely what will unfold, the journey to an undetermined destination on the open road, intangible experiences such as feeling one with a much larger and more powerful natural world, the challenge of correctly forecasting and intercepting storms with optimal vantage points, and pure thrill seeking. Pecuniary interests and competition may also be components; in contrast, camaraderie is common.

Although scientific work is sometimes cited as a goal, direct participation in such work is almost always impractical during the actual chase except for chasers collaborating in an organized university or government project. Many chasers also act as storm spotters, reporting their observations of hazardous weather to relevant authorities. These reports greatly benefit real-time warnings with ground truth information, as well as science as a whole by increasing the reliability of severe storm databases used in climatology and other research (which ultimately boosts forecast and warning skill). Additionally, many recreational chasers submit photos and videos to researchers as well as to the U.S. National Weather Service (NWS) for spotter training.

Storm chasers are not generally paid to chase, with the exception of television media crews in certain television market areas, video stringers and photographers (freelancers mostly, but some staff), and researchers such as graduate meteorologists and professors. An increasing number sell storm videos and pictures and manage to make a profit. A few operate "chase tour" services, making storm chasing a recently developed form of niche tourism. Financial returns usually are relatively meager given the expenses of chasing, with most chasers spending more than they take in and very few making a living solely from chasing. Chasers are also generally limited by the duration of the season in which severe storms are most likely to develop, usually the local spring and/or summer.

No degree or certification is required to be a storm chaser, and many chases are mounted independently by amateurs and enthusiasts without formal training. Local National Weather Service offices do hold storm spotter training classes, usually early in the spring. Some offices collaborate to produce severe weather workshops oriented toward operational meteorologists.

Storm chasers come from a wide variety of occupational and socioeconomic backgrounds. Though a fair number are professional meteorologists, most storm chasers are from other occupational fields, which may include any number of professions that have little or nothing to do with meteorology. A relatively high proportion possess college degrees and a large number live in the central and southern United States. Many are lovers of nature with interests that also include flora, fauna, geology, volcanoes, aurora, meteors, eclipses, and astronomy.

History

The first person to gain public recognition as a storm chaser was David Hoadley (born 1938), who began chasing North Dakota storms in 1956, systematically using data from area weather offices and airports. He is widely considered the pioneer storm chaser and was the founder and first editor of Storm Track magazine.

Neil B. Ward (1914–1972) subsequently brought research chasing to the forefront in the 1950s and 1960s, enlisting the help of the Oklahoma Highway Patrol to study storms. His work pioneered modern storm spotting and made institutional chasing a reality.

The first coordinated storm chasing activity sponsored by institutions was undertaken as part of the Alberta Hail Studies project beginning in 1969. Vehicles were outfitted with various meteorological instrumentation and hail-catching apparatus and were directed into suspected hail regions of thunderstorms by a controller at a radar site. The controller communicated with the vehicles by radio.

In 1972, the University of Oklahoma (OU) in cooperation with the National Severe Storms Laboratory (NSSL) began the Tornado Intercept Project, with the first outing taking place on 19 April of that year. This was the first large-scale tornado chasing activity sponsored by an institution. It culminated in a brilliant success in 1973 with the Union City, Oklahoma tornado providing a foundation for tornado and supercell morphology that proved the efficacy of storm chasing field research. The project produced the first legion of veteran storm chasers, with Hoadley's Storm Track magazine bringing the community together in 1977.

Storm chasing then reached popular culture in three major spurts: in 1978 with the broadcast of an episode of the television program In Search of...; in 1985 with a documentary on the PBS series Nova; and in May 1996 with the theatrical release of Twister, a Hollywood blockbuster which provided an action-packed but heavily fictionalized glimpse of the hobby. Further early exposure to storm chasing resulted from notable magazine articles, beginning in the late 1970s in Weatherwise magazine.

Various television programs and increased coverage of severe weather by the news media, especially since the initial video revolution in which VHS ownership became widespread by the early 1990s, substantially elevated awareness of and interest in storms and storm chasing. The Internet in particular has contributed to a significant increase in the number of storm chasers since the mid-to-late 1990s. A sharp increase in the general public impulsively wandering about their local area in search of tornadoes similarly is largely attributable to these factors. The 2007–2011 Discovery Channel reality series Storm Chasers produced another surge in activity. Over the years the nature of chasing and the characteristics of chasers shifted.

From their advent in the 1970s until the mid-1990s, scientific field projects were occasionally conducted in the Great Plains during the spring. The first of the seminal VORTEX projects occurred in 1994–1995 and was soon followed by various field experiments each spring, with another large project, VORTEX2, in 2009–2010. Since the mid-1990s, most storm chasing science, with the notable exception of large field projects, consists of mobile Doppler weather radar intercepts.

Typical storm chase

Chasing often involves driving thousands of miles in order to witness the relatively short window of time of active severe thunderstorms. It is not uncommon for a chaser to end up empty handed on any particular day. Storm chasers' degrees of involvement, competencies, philosophies, and techniques vary widely, but many chasers spend a significant amount of time forecasting, both before going on the road as well as during the chase, utilizing various sources for weather data. Most storm chasers are not meteorologists, and many chasers expend significant time and effort in learning meteorology and the intricacies of severe convective storm prediction through both study and experience.

Besides the copious driving to, from, and during chases, storm chasing is punctuated with contrasting periods of long waiting and ceaseless action. Downtime can consist of sitting under sun-baked skies for hours, playing pickup sports, evaluating data, or visiting landmarks while awaiting convective initiation. During an inactive pattern, this down time can persist for days. When storms are occurring, there is often little or no time to eat or relieve oneself and finding fuel can cause frustrating delays and detours. Navigating obstacles such as rivers and areas with inadequate road networks is a paramount concern. Only a handful of chasers decide to chase in Dixie Alley, an area of the Southern United States in which trees and road networks heavily obscure the storms and often large tornadoes. The combination of driving and waiting has been likened to "extreme sitting". A "bust" occurs when storms do not fire, sometimes referred to as "severe clear", when storms fire but are missed, when storms fire but are meager, or when storms fire after dusk.

Most chasing is accomplished by driving a motor vehicle of any make or model, whether it be a sedan, van, pickup truck, or SUV, however, a few individuals occasionally fly planes and television stations in some markets use helicopters. Research projects sometimes employ aircraft, as well.

Geographical, seasonal, and diurnal activity

Storm chasers are most active in the spring and early summer, particularly May and June, across the Great Plains of the United States (extending into Canada) in an area colloquially known as Tornado Alley, with many hundred individuals active on some days during this period. This coincides with the most consistent tornado days in the most desirable topography of the Great Plains. Not only are the most intense supercells common here, but due to the moisture profile of the atmosphere the storms tend to be more visible than locations farther east where there are also frequent severe thunderstorms. There is a tendency for chases earlier in the year to be farther south, shifting farther north with the jet stream as the season progresses. Storms occurring later in the year tend to be more isolated and slower moving, both of which are also desirable to chasers.

Chasers may operate whenever significant thunderstorm activity is occurring, whatever the date. This most commonly includes more sporadic activity occurring in warmer months of the year bounding the spring maximum, such as the active month of April and to a lesser extent March. The focus in the summer months is the Central or Northern Plains states and the Prairie Provinces, the Upper Midwest, or on to just east of the Colorado Front Range. An annually inconsistent and substantially smaller peak of severe thunderstorm and tornado activity also arises in the transitional months of autumn, particularly October and November. This follows a pattern somewhat the reverse of the spring pattern with the focus beginning in the north then dropping south and with an overall eastward shift. In the area with the most consistent significant tornado activity, the Southern Plains, the tornado season is intense but is relatively brief whereas central to northern and eastern areas experience less intense and consistent activity that is diffused over a longer span of the year.

Advancing technology since the mid-2000s led to chasers more commonly targeting less amenable areas (i.e. hilly or forested) that were previously eschewed when continuous wide visibility was critical. These advancements, particularly in-vehicle weather data such as radar, also led to an increase in chasing after nightfall. Most chasing remains during daylight hours with active storm intercepting peaking from mid-late afternoon through early-to-mid evening. This is dictated by a chaser's schedule (availability to chase) and by when storms form, which usually is around peak heating during the mid-to-late afternoon but on some days occurs in early afternoon or even in the morning. An additional advantage of later season storms is that days are considerably longer than in early spring. Morning or early afternoon storms tend to be associated with stronger wind shear and thus most often happen earlier in the spring season or later during the fall season.

Some organized chasing efforts have also begun in the Top End of the Northern Territory and in southeastern Australia, with the biggest successes in November and December. A handful of individuals are also known to be chasing in other countries, including the United Kingdom, Israel, Italy, Spain, France, Belgium, the Netherlands, Finland, Germany, Austria, Switzerland, Poland, Bulgaria, Slovenia, Hungary, the Czech Republic, Slovakia, Estonia, Argentina, South Africa, Bangladesh, and New Zealand; although many people trek to the Great Plains of North America from these and other countries around the world (especially from the UK). The number of chasers and number countries where chasers are active expanded at an accelerating pace in Europe from the 1990s–2010s.

Dangers

There are inherent dangers involved in pursuing hazardous weather. These range from lightning, tornadoes, large hail, flooding, hazardous road conditions (rain or hail-covered roadways), animals on the roadway, downed power lines (and occasionally other debris), reduced visibility from heavy rain (often wind blown), blowing dust, and hail fog. Most directly weather-related hazards such as from a tornado are minimized if the storm chaser is knowledgeable and cautious. In some situations severe downburst winds may push automobiles around, especially high-profile vehicles. Tornadoes affect a relatively small area and are predictable enough to be avoided if sustaining situational awareness and following strategies including always having an open escape route, maintaining a safe distance, and avoiding placement in the direction of travel of a tornado (in most cases in the Northern Hemisphere this is to the north and to the east of a tornado). Lightning, however, is an unavoidable hazard. "Core punching", storm chaser slang for driving through a heavy precipitation core to intercept the area of interest within a storm, is recognized as hazardous due to reduced visibility and because many tornadoes are rain-wrapped. The "bear's cage" refers to the area under a rotating wall cloud (and any attendant tornadoes), which is the "bear", and to the blinding precipitation (which can include window-shatteringly large hail) surrounding some or all sides of a tornado, which is the "cage". Similarly, chasing at night heightens risk due to darkness.

In reality, the most significant hazard is driving, which is made more dangerous by the severe weather. Adding still more to this hazard are the multiple distractions which can compete for a chaser's attention, such as driving, communicating with chase partners and others with a phone and/or radio, navigating, watching the sky, checking weather data, and shooting photos or video. Again here, prudence is key to minimizing the risk. Chasers ideally work to prevent the driver from multitasking either by chase partners covering the other aspects or by the driver pulling over to do these other things if he or she is chasing alone. Falling asleep while driving is a chase hazard, especially on long trips back. This also is exacerbated by nocturnal darkness and by the defatigating demands of driving through precipitation and on slick roads.

Incidents

For nearly 60 years, the only known chaser deaths were driving-related. The first was Christopher Phillips, an OU undergraduate student, killed in a hydroplaning accident when swerving to miss a rabbit in 1984. Other incidents included Jeff Wear driving home from a hurricane chase in 2005, when Fabian Guerra swerved to miss a deer while driving to a chase in 2009, and when a wrong-way driver resulted in a head-on collision that killed Andy Gabrielson who was returning from a chase in 2012. On May 31, 2013, an extreme event led to the first known chaser deaths inflicted directly by weather when the widest tornado ever recorded struck near El Reno, Oklahoma. Engineer Tim Samaras, his photographer son Paul, and meteorologist Carl Young were killed by the tornado while doing in situ probe and infrasonic field research. In an exceptional combination of events, the already large and rain-obscured tornado swelled to 2.6 miles (4.2 km) wide in under a minute as it simultaneously changed direction and accelerated. Several other chasers were also struck and some injured by this tornado and its parent supercell's rear flank downdraft (RFD). Three chasers were killed, two in one vehicle and one in another, when their vehicles collided in West Texas in 2017. Another fatality occurred on the morning of June 20, 2019. Dale Sharpe, an Australian, struck a deer and subsequently became disabled. As he stepped out of the vehicle, an oncoming vehicle struck him and he later died at the hospital. The most recent chasing-related fatalities were on April 29, 2022, when three OU meteorology students were killed after hydroplaning on Interstate 35 near Tonkawa while returning from a storm chase.

There are other incidents in which chasers were injured by automobile accidents, lightning strikes, and tornado impacts. While chasing a tornado outbreak on 13 March 1990, KWTV television photographer Bill Merickel was shot and injured near Lindsay, Oklahoma.

Equipment

Storm chasers vary with regards to the amount of equipment used, some prefer a minimalist approach; for example, where only basic photographic equipment is taken on a chase, while others use everything from satellite-based tracking systems and live data feeds to vehicle-mounted weather stations and hail guards.

Historic

Top of a NSSL chase vehicle showing air conditioning unit, compass, and Global Positioning System.

Historically, storm chasing relied on either in-field analysis or in some cases nowcasts from trained observers and forecasters. The first in-field technology consisted of radio gear for communication. Much of this equipment could also be adapted to receive radiofax data which was useful for receiving basic observational and analysis data. The primary users of such technology were university or government research groups who often had larger budgets than individual chasers.

Radio scanners were also heavily used to listen in on emergency services and storm spotters so as to determine where the most active or dangerous weather was located. A number of chasers were also radio amateurs, and used mobile (or portable) amateur radio to communicate directly with spotters and other chasers, allowing them to keep abreast of what they could not themselves see.

It was not until the mid- to late 1980s that the evolution of the laptop computer would begin to revolutionize storm chasing. Early on, some chasers carried acoustic couplers to download batches of raw surface and upper air data from payphones. The technology was too slow for graphical imagery such as radar and satellite data; and during the first years this wasn't available on any connection over telephone lines, anyway. Some raw data could be downloaded and plotted by software, such as surface weather observations using WeatherGraphix (predecessor to Digital Atmosphere) and similar software or for upper air soundings using SHARP, RAOB, and similar software.

Most meteorological data was acquired all at once early in the morning, and the rest of day's chasing was based on analysis and forecast gleaned from this; as well as on visual clues that presented themselves in the field throughout the day. Plotted weather maps were often analyzed by hand for manual diagnosis of meteorological patterns. Occasionally chasers would make stops at rural airstrips or NWS offices for an update on weather conditions. NOAA Weather Radio (NWR) could provide information in the vehicle, without stopping, such as weather watches and warnings, surface weather conditions, convective outlooks, and NWS radar summaries. Nowadays, storm chasers may use high-speed Internet access available in any library, even in small towns in the US. This data is available throughout the day, but one must find and stop at a location offering Internet access.

With the development of the mobile computers, the first computer mapping software became feasible, at about the same time as the popular adoption of the VHS camcorder began a rapid growth phase. Prior to the mid to late 1980s most motion picture equipment consisted of 8 mm film cameras. While the quality of the first VHS consumer cameras was quite poor (and the size somewhat cumbersome) when compared to traditional film formats, the amount of video which could be shot with a minimal amount of resources was much greater than any film format at the time.

In the 1980s and 1990s The Weather Channel (TWC) and A.M. Weather were popular with chasers, in the morning preceding a chase for the latter and both before and during a chase for the former. Commercial radio sometimes also provides weather and damage information. The 1990s brought technological leaps and bounds. With the swift development of solid state technology, television sets for example could be installed with ease in most vehicles allowing storm chasers to actively view local TV stations. Mobile phones became popular making group coordination easier when traditional radio communications methods were not ideal or for those possessing radios. The development of the World Wide Web (WWW) in 1993 hastened adoption of the Internet and led to FTP access to some of the first university weather sites.

The mid-1990s marked the development of smaller more efficient marine radars. While such marine radars are illegal if used in land-mobile situations, a number of chasers were quick to adopt them in an effort to have mobile radar. These radars have been found to interfere with research radars, such as the Doppler on Wheels (DOW) utilized in field projects. The first personal lightning detection and mapping devices also became available and the first online radar data was offered by private corporations or, at first with delays, with free services. A popular data vendor by the end of the 1990s was WeatherTAP.

Current

A heavily armored Tornado Intercept Vehicle used to film inside a tornado with an IMAX camera, and featured in the Discovery Channel series, Storm Chasers.

 

An SRV, a.k.a. "The Dominator", featured in the Discovery Channel series, Storm Chasers.

Chasers used paper maps for navigation and some of those now using GPS still use these as a backup or for strategizing with other chasers. Foldable state maps can be used but are cumbersome due to the multitude of states needed and only show major roads. National atlases allow more detail and all states are contained in a single book, with AAA favored and Rand McNally followed by Michelin also used. The preferred atlases due to great detail in rural areas are the "Roads of..." series originally by Shearer Publishing, which first included Texas but expanded to other states such as Oklahoma and Colorado. Covering every state of the union are the DeLorme "Atlas and Gazetteer" series. DeLorme also produced early GPS receivers that connected to laptops and for years was one of two major mapping software creators. DeLorme Street Atlas USA or Microsoft Streets & Trips were used by most chasers until their discontinuations in 2013. Chasers now use Google Maps or other web mapping as no suitable alternative mapping software emerged. GPS receivers may still be used with other software, such as for displaying radar data.

A major turning point was the advent of civilian GPS in 1996. At first, GPS units were very costly and only offered basic functions, but that would soon change. Towards the late 1990s the Internet was awash in weather data and free weather software, the first true cellular Internet modems for consumer use also emerged providing chasers access to data in the field without having to rely on a nowcaster. The NWS also released the first free, up-to-date NEXRAD Level 3 radar data. In conjunction with all of this, GPS units now had the ability to connect with computers, granting greater ease when navigating.

2001 marked the next great technological leap for storm chasers as the first Wi-Fi units began to emerge offering wireless broadband service in many cases for free. Some places (restaurants, motels, libraries, etc.) were known to reliably offer wireless access and wardriving located other availabilities. In 2002 the first Windows-based package to combine GPS positioning and Doppler radar appeared called SWIFT WX. SWIFT WX allowed storm chasers to seamlessly position themselves accurately relative to tornadic storms.

In 2004 two more storm chaser tools emerged. The first, WxWorx, was a new XM Satellite Radio based system utilizing a special receiver and Baron Services weather software. Unlike preexisting cellular based services there was no risk of dead spots, and that meant that even in the most remote areas storm chasers still had a live data feed. The second tool was a new piece of software called GRLevel3. GRLevel3 utilized both free and subscription based raw radar files, displaying the data in a true vector format with GIS layering abilities. Since 2006 a growing number of chasers are using Spotter Network (SN), which uses GPS data to plot real time position of participating spotters and chasers, and allows observers to report significant weather as well as GIS layering for navigation maps, weather products, and the like.

The most common chaser communications device is the cellular phone. These are used for both voice and data connections. External antennas and amplifiers may be used to boost signal transception. It is not uncommon that chasers travel in small groups of cars, and they may use CB radio (declining in use) or inexpensive GMRS / FRS hand-held transceivers for inter-vehicle communication. More commonly, many chasers are also ham radio operators and use the 2 meters VHF and, less often, 70 cm UHF bands to communicate between vehicles or with Skywarn / Canwarn spotter networks. Scanners are often used to monitor spotter, sometimes public safety communications, and can double as weather radios. Since the mid-2000s social networking services may also be used, with Twitter most used for ongoing events, Facebook for sharing images and discussing chase reports, and Instagram trailing in adoption. Social networking services largely (but not completely) replace forums and email lists, which complemented and eventually supplanted Stormtrack magazine, for conversing about storms.

In-field environmental data is still popular among some storm chasers, especially temperature, moisture, and wind speed and direction data. Many have chosen to mount weather stations atop their vehicles. Others use handheld anemometers. Rulers or baseballs may be brought along for measuring hail and for showing as a comparison object. Vehicle mounted cameras, such as on the roof or more commonly on the dash, provide continuous visual recording capability.

Chasers heavily utilized still photography since the beginning. Videography gained prominence by the 1990s into the early 2000s but a resurgence of photography occurred with the advent of affordable and versatile digital SLR (DSLR) cameras. Prior to this, 35 mm SLR print and slide film formats were mostly used, along with some medium format cameras. In the late 2000s, mobile phone 3G data networks became fast enough to allow live streaming video from chasers using webcams. This live imagery is frequently used by the media, as well as NWS meteorologists, emergency managers, and the general public for direct ground truth information, and it promotes video sales opportunities for chasers. Also by this time, camcorders using memory cards to record video began to be adopted. Digital video had been around for years but was recorded on tape, whereas solid-state is random access rather than sequential access (linear) and has no moving parts. Late in the 2000s HD video began to overtake SD (which had been NTSC in North America) in usage as prices came down and performance increased (initially there were low-light and sporadic aliasing problems due to chip and sensor limitations). By the mid-2010s 4K cameras were increasingly in use. Tripods are used by those seeking crisp professional photo and video imagery and also enable chasers to tend to other activities. Other accessories include cable/remote shutter releases, lightning triggers, and lens filters. Windshield mounted cameras or dome enclosed cameras atop vehicle roofs may also be used, and a few chasers use UAVs ("drones").

Late in the 2000s smartphones increased in usage, with radar viewing applications frequently used. Particularly, RadarScope on the iOS and Android platforms is favored. Pkyl3 was a dominant early choice on Android devices which discontinued development in August 2018. Other apps may be used as are browsers for viewing meteorological data and accessing social networking services. Some handsets can be used as WiFi hotspots and wireless cards may also be used to avoid committing a handset to tethering or operating as a hotspot. Some hotspots operate as mobile broadband MNVO devices using any radio spectrum that is both available and is in contract with a service provider. Such devices may expand mobile data range beyond a single carrier's service area and typically can work on month-to-month contracts. Adoption of tablet computers expanded by the early 2010s. 4G LTE has been adopted when available and can be especially useful for uploading HD video. A gradual uptick of those selecting mirrorless interchangeable-lens cameras (MILCs) began in the mid-2010s. Usage of DSLR for video capture, called HDSLR, is common, although HD camcorders remain popular due to their greater functionality (many chasers still shoot both).

Chasers also carry common travel articles and vehicle maintenance items, and sometimes first aid kits. Full sized spare tires are strongly preferable to "donut" emergency replacement tires. Power inverters (often with surged protected power strips) power devices that require AC (indoor/wall outlet) power, although some devices may be powered directly with DC (battery power) from the vehicle electric system. Water repellent products, such as Rain-X or Aquapel, are frequently applied to windshields to dispel water when driving as well as mud and small detritus, which boosts visibility and image clarity on photographs and videos shot through glass (which is particularly problematic if autofocus is on). Binoculars and sunglasses are commonly employed.

Ethics

A growing number of experienced storm chasers advocate the adoption of a code of ethics in storm chasing featuring safety, courtesy, and objectivity as the backbone. Storm chasing is a highly visible recreational activity (which is also associated with science) that is vulnerable to sensationalist media promotion. Veteran storm chasers Chuck Doswell and Roger Edwards deemed reckless storm chasers as "yahoos". Doswell and Edwards believe poor chasing ethics at TV news stations add to the growth of "yahoo" storm chasing. A large lawsuit was filed against the parent company of The Weather Channel in March 2019 for allegedly keeping on contract storm chaser drivers with a demonstrated pattern of reckless driving which ultimately led in a fatal collision (killing themselves and a storm spotter in the other vehicle) when running a stop sign in Texas in 2017. Edwards and Rich Thompson, among others, also expressed concern about pernicious effects of media profiteering with Matt Crowther, among others, agreeing in principle but viewing sales as not inherently corrupting. Self-policing is seen as the means to mold the hobby. There is occasional discussion among chasers that at some point government regulation may be imposed due to increasing numbers of chasers and because of poor behavior by some individuals; however, many chasers do not expect this eventuality and almost all oppose regulations -—as do some formal studies of dangerous leisure activities which advocate deliberative self-policing.

As there is for storm chaser conduct, there is concern about chaser responsibility. Since some chasers are trained in first aid and even first responder procedures, it is not uncommon for tornado chasers to be first on a scene and tending to storm victims or treating injuries at the site of a disaster in advance of emergency personnel and other outside aid.

Aside from questions concerning their ethical values and conduct, many have been accredited for giving back to the community in several ways. Just before the Joplin tornado, Storm Chaser Jeff Piotrowski provided advanced warning to Officer Brewer of Joplin local law enforcement, prompting them to activate the emergency sirens. Though lives were lost, many who survived accredited their survival to the siren. After a storm has passed storm chasers are often the first to arrive on the scene to help assist in the aftermath. An unexpected and yet increasingly more common result of storm chasers is the data they provide to storm research from their videos, social video posts and documentation of storms they encounter. After the El Reno tornado in 2013, portals were created for chasers to submit their information to help in the research of the deadly storm. The El Reno Tornado Environment Display (TED) was created to show a synchronized view of the submitted video footage overlaying radar images of the storm with various chasers' positions.

In popular culture

• Twister, a 1996 film starring Helen Hunt and Bill Paxton
• Into the Storm, a 2014 film
• Heavy Weather, a novel