What is stepped leader stroke?
In thunderstorm: Initial stroke. …to thousands of amperes, the stepped leader propagates toward the ground at an average velocity of 1.5 × 105 metres per second, or about one two-thousandth the speed of light. It is called a stepped leader because of its downward-moving “stepped” pulses of luminosity.
What is the stepped ladder?
A stepladder is a portable, self-supporting, A-frame ladder. It has two front side rails and two rear side rails. Generally, there are steps mounted between the front side rails and bracing between the rear side rails.
What is a stepped leader an upward streamer and a return stroke?
The connection between the stepped leader and the upward discharge creates a “short circuit” between the charge in the cloud and the charge in the ground. A powerful current travels back up the channel from the ground toward the cloud. This is the 1st return stroke.
What is a leader lightning?
initiation of lightning In lightning. Next, a stepped leader (initial lightning stroke) forms and propagates downward, following channels created by the preliminary breakdown process. The leader is highly branched in the direction of its propagation. Most leader channels are negatively charged.
What is a stepped leader simple definition?
[′stept ′lēd·ər] (geophysics) The initial streamer of a lightning discharge; an intermittently advancing column of high ion density which established the channel for subsequent return streamers and dart leaders.
What is DART leader?
(Also called continuous leader.) The leader which, after the first stroke, typically initiates each succeeding stroke of a multiple-stroke flash lightning. (The first stroke is initiated by a stepped leader.) The dart leader derives its name from its appearance on photographs taken with streak cameras.
What is a dart leader?
What happens when a stepped leader meets an upward leader?
Stepped leaders tend to branch out as they seek a connection with the positive charge on the ground. When a branch of the stepped leader reaches within about 50 meters of the ground or some object on the ground, it connects with an upward-developing positive charge, often referred to as an upward streamer.
What is an upward leader?
Upward Leadership: Guiding the Whole Team Towards Success. The theory of upward leadership revolves around a set of skills that together, allow a person to effectively influence his or her leader in order to bring success to the entire team.
What is a upward leader?
An effective upward leader thinks critically and respectfully lets their leader know when they disagree on an issue. This point is different in every situation, but the astute upward leader knows how far they can push a disagreement without being disrespectful or being disloyal.
What is return stroke?
The return stroke is the very bright visible flash that we see as lightning, caused by the rapid discharge of electricity. Once the step leader makes contact with a streamer, the negative charge that has accumulated along the leader channel flows rapidly to ground.
How fast is lightning return stroke?
around 100,000 km/s
The rate at which the return stroke current travels has been found to be around 100,000 km/s (one-third of the speed of light).
What is sheet lightning?
Sheet lightning, also known as intra-cloud lightning, refers to lightning within a cloud that lights up as a ‘sheet’ of luminosity during the flash. The lightning itself can’t be seen by a spectator, so it appears as a flash, or sheet of light.
What is a return stroke?
What are lightning streamers?
Simply put, during a storm a charge builds in the cloud, eventually generating a step leader which descends from the cloud. In reaction, streamers are launched from ground-based objects. The two connect and a strike is formed.
What is reverse lightning?
A flash of light in the sky caused by an electrical discharge from the Earth’s surface to a cloud. Reverse lightning is so called because lightning typically occurs between clouds or travels from a cloud to the Earth’s surface. Also called return stroke See note at lightning.
What is upward lightning?
The most important finding about upward lightning, is that it primarily occurs when there is a nearby positive cloud-to-ground flash. The electric field change caused by the preceding flash causes an upward positive leader to initiate from a tall object such as a building, tower or wind turbine.
What is an example of a stepped leader?
Stepped Leader. Stepped leader An initial discharge of electrons that proceeds intermittently toward the ground in a series of steps in a cloud-to-ground lightning stroke. Storm surge An abnormal rise of the sea along a shore; primarily due to the winds of a storm, especially a hurricane.
What is a stepped leader in Lightning?
Stepped leader s are the initial electrical discharge s in a lightning, consisting of negative electrical charge that travel from the cloud base to within 100 m of the ground. It is usually invisible to the human eye. [>>>]
Which way does a stepped leader branch?
In addition, the stepped leader generally branches outward as it seeks a connection to the ground. Depending on the electric field surrounding the step leader, individual branches of the leader may become more or less prominent, Figure 5.