foryevg alfredas sherrey

[Carlito Austin]

Sprites or red sprites are large-scale electric discharges that occur in the mesosphere, high above thunderstorm clouds, or cumulonimbus, giving rise to a varied range of visual shapes flickering in the night sky. They are usually triggered by the discharges of positive lightning between an underlying thundercloud and the ground.

Sprites are sometimes inaccurately called upper-atmospheric lightning. However, they are cold plasma phenomena that lack the hot channel temperatures of tropospheric lightning, so they are more akin to fluorescent tube discharges than to lightning discharges. Sprites are associated with various other upper-atmospheric optical phenomena including blue jets and ELVES.[1]

The earliest known report is by Toynbee and Mackenzie in 1886.[3] Nobel laureate C. T. R. Wilson had suggested in 1925, on theoretical grounds, that electrical breakdown could occur in the upper atmosphere, and in 1956 he witnessed what possibly could have been a sprite. They were first documented photographically on July 6, 1989, when scientists from the University of Minnesota, using a low-light video camera, accidentally captured the first image of what would subsequently become known as a sprite.[4]

Several years after their discovery they were named sprites (air spirits) after their elusive nature.[5] Since the 1989 video capture, sprites have been imaged from the ground, from aircraft and from space, and have become the subject of intensive investigations. A featured high speed video that was captured by Thomas Ashcraft, Jacob L Harley, Matthew G McHarg, and Hans Nielsen in 2019 at about 100,000 frames per second is fast enough to provide better detailing of how sprites develop. However, according to NASA's APOD blog, despite being recorded in photographs and videos for the more than 30 years, the "root cause" of sprite lightning remains unknown, "apart from a general association with positive cloud-to-ground lightning." NASA also notes that not all storms exhibit sprite lightning.[6]

Sprites have been observed over North America,[9] Central America, South America,[10] Europe,[11] Central Africa (Zaire), Australia, the Sea of Japan and Asia and are believed to occur during most large thunderstorm systems.

Sprites are colored reddish-orange[5] in their upper regions, with bluish hanging tendrils below, and can be preceded by a reddish halo. They last longer than normal lower stratospheric discharges, which last typically a few milliseconds, and are usually triggered by the discharges of positive lightning between the thundercloud and the ground,[12] although sprites generated by negative ground flashes have also been observed.[13] They often occur in clusters of two or more, and typically span the altitude range 50 to 90 kilometres (31 to 56 mi), with what appear to be tendrils hanging below, and branches reaching above.[5]

Sprites occur near the top of the mesosphere at about 80 km altitude in response to the electric field generated by lightning flashes in underlying thunderstorms. When a sufficiently large positive lightning strike carries charges to the ground, the cloud top is left with a strongly negative net charge. This can be modeled as a quasi-static electric dipole and for less than 10 milliseconds a strong electric field is generated in the region above the thunderstorm. In the low pressure of the upper mesosphere the breakdown voltage is drastically reduced, allowing for an electron avalanche to occur.[16][17] Sprites get their characteristic red color from excitation of nitrogen in the low pressure environment of the upper mesosphere. At such low pressures quenching by atomic oxygen is much faster than that of nitrogen, allowing for nitrogen emissions to dominate despite no difference in composition.[18][19]

Sprites are sometimes preceded, by about 1 millisecond, by a sprite halo, a pancake-shaped region of weak, transient optical emissions approximately 50 kilometres (31 mi) across and 10 kilometres (6.2 mi) thick. The halo is centered at about 70 kilometres (43 mi) altitude above the initiating lightning strike. These halos are thought to be produced by the same physical process that produces sprites, but for which the ionization is too weak to cross the threshold required for streamer formation. They are sometimes mistaken for ELVES, due to their visual similarity and short duration.[20][21][22]

Research carried out at Stanford University in 2000 indicates that, unlike sprites with bright vertical columnar structure, occurrence of sprite halos is not unusual in association with normal (negative) lightning discharges.[22]Research in 2004 by scientists from Tohoku University found that very low frequency emissions occur at the same time as the sprite, indicating that a discharge within the cloud may generate the sprites.[23]

Sprites have been blamed for otherwise unexplained accidents involving high altitude vehicular operations above thunderstorms. One example of this is the malfunction of a NASA stratospheric balloon launched on June 6, 1989, from Palestine, Texas. The balloon suffered an uncommanded payload release while flying at 120,000 feet (37,000 m) over a thunderstorm near Graham, Texas. Months after the accident, an investigation concluded that a "bolt of lightning" traveling upward from the clouds provoked the incident.[24] The attribution of the accident to a sprite was made retroactively, since this term was not coined until late 1993.

Keep in mind that with JavaScript and GameLab, the order of the functions called matters. If you want the text to be in the foreground, call it after the drawSprites function. If you want a layered effect, just takes some logic to figure out what is called/drawn first.

The technique mentioned above should work- here is an example. You still need to draw the other sprites using drawSprites() and then use the drawSprite(pump) to layer the pumpkin on top. It is beyond the scope of the curriculum but does solve your problem of layering drawn sprites with text.

I'm trying to write a code that upon user input changes the ghost effect of several different banks of sprites based on the number. For example if the user types in "1" sprites 9, 11, 17, and 20 appear. Is there any way to do this using a list?

(I know I'm mentioning I'm a js dev)
As a js game dev, I always advise to store your sprites (or at least clones) in lists, when non-block programming.
This is an concept that has been used for almost every game, so it should be possible

I deleted my post why did you reply to it
besides you also reinitialized the variable in your code
Edit: ohh wait, i see how you could use that. but personally I just prefer to use an if statement in the js

Sir even I know that these boards are for everyone to see but the fact is that the project which I am speaking about is a part of my submission at the HACKATHON 2020 that is why... after this week ends, i will make my aia file public, but please consider taking a look at it once, I shall be highly obliged,
Thanks

The only problem is that the if statement needs to check if all sprites are not visible, but it starts displaying that message only when one sprite has been made invisible...
That is the whole point of my question...

Paul picks me and another chaser up from Oklahoma City. We drive south into Texas. Paul uses radar images to identify the storms with potential for sprites. The storms need to meet some conditions: they need to be intense, capable of producing strong positive cloud-to-ground lightning; must be stationary or slow moving; must continue into the night when sprites can be photographed. Storms created or supported by a low level jet may meet these conditions.

Once he decides on a target, he looks at positioning. The ideal distance to the storm is between 100 and 300 miles. At that distance, you can see the sprites above clouds. There must be minimal light pollution where you are and all the way to the storm.

The first night turns out to have been the best. On the second night the sky between us and some more distant storms is rather light polluted and no sprites can be photographed. On the third night we are in Big Bend National Park to aim at some storms in Mexico. No success here either, although we have an opportunity to photograph lightning produced by a smaller storm not too far, and have a superb view of the Milky Way.

Looking back, this was an exceptional experience. Of course, I was able to get the sprite photographs (one of which was among the finalists in the Weather Band 2022 Photo contest), but I also greatly enjoyed the company of people with the same interests as well as seeing new places, watching storms in an open field by day and being under clear dark skies at night.

Hi! I'm new to App Inventor. I came from Scratch, so I'm used to having the ability to clone sprites. I'm currently making a coding program on App Inventor, but I need the clone block in order to show the blocks. Could someone help me?

? Dynamic Components Extension that supports every component in your AI2 distribution, instead of having pre-defined components. I thought about making a full method to create all dynamic components without creating different blocks for every...

We will take this under consideration. App Inventor was developed at a time when smartphone resources were very restrictive (app were allowed 8 MB of RAM, max, and loading a couple images could exhaust that) and so memory usage was a big consideration for design decisions. Now that apps can have hundreds of megabytes available, it's more feasible to let apps dynamically create components. The Map component already allows this either through the CreateMarker method or via loading feature collections. Extending the logic to other components seems reasonable.

You never actually told us the context of your requirement. If the number of Sprite copies is huge, then the extension is the way to go - but if there will only be a few copies, then making pre-copies and hiding them is a good method.

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