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  • Irish Chronicles Document Links Between Volcanoes and Weather
    A study of over 40,000 written entries in Irish Annals and ice core measurements shows a strong corr...Read more

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    Irish Chronicles Document Links Between Volcanoes and Weather

    A study of over 40,000 written entries in Irish Annals and ice core measurements shows a strong correlation between the occurrence of volcanic eruptions and extreme cold weather in Ireland over a 1200 year period. Data analyzed in this study cover the period from 431 to 1649, during which time up to 48 volcanic eruptions are identified in Greenland ice core records through deposition of volcanic sulfate in annual layers of ice. You can find the study (open access), published on 6 June 2013 in IOP Publishing's journal Environmental Research Letters, at http://iopscience.iop.org/1748-9326/8/2/024035/article. Find out more about how volcanoes can influence climate.
  • EF-5 Tornado in El Reno, Oklahoma Widest Ever Recorded in US
    The EF-5 tornado that hit El Reno, Oklahoma on May 31st was the widest ever recorded in the US, acco...Read more

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    EF-5 Tornado in El Reno, Oklahoma Widest Ever Recorded in US

    The EF-5 tornado that hit El Reno, Oklahoma on May 31st was the widest ever recorded in the US, according to the National Weather Service in Norman Oklahoma. The tornado, which remained on the ground for 40 minutes and reached 2.6 miles across (4.2 km), took the lives of 18 people including storm chasers Tim Samaras, Paul Samaras and Carl Young. For more information on the tornado, visit http://ow.ly/i/2hfDG.
  • Atmospheric CO2 Level Tops 400 ppm
    During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm rep...Read more

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    Atmospheric CO2 Level Tops 400 ppm

    During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm repeatedly. Daily levels of CO2 can vary due to weather, and there are seasonal trends as well. The level of atmospheric greenhouse gases continues to increase, now over 120 ppm since the Industrial Revolution began. For more on the Keeling Curve, see http://keelingcurve.ucsd.edu/. Find out more about greenhouse gases and warming.

Mature Stage

When the cumulus cloud becomes very large, the water molecules in it become large and heavy. They start to fall through the cloud when the rising air can no longer hold them up. Meanwhile, cool dry air starts to enter the cloud. This is known as entrainment. Because cool air is heavier than warm air, it starts to descend in the cloud (known as a downdraft). The downdraft pulls the heavy water molecules downward, making rain.

This cloud has become a cumulonimbus cloud because it has an updraft, a downdraft, and precipitation. Lightning and thunder start to occur, as well as heavy rain. The cumulonimbus is now a thunderstorm cell.

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Traveling Nitrogen Classroom Activity Kit

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Rain

Rain is precipitation that falls to the Earth in drops of 5mm or greater in diameter according to the US National Weather Service. Virga is rain that evaporates before reaching the ground. Raindrops form...more

Cumulonimbus

Cumulonimbus (weather symbol - Cb) clouds belong to the Clouds with Vertical Growth group. They are generally known as thunderstorm clouds. A cumulonimbus cloud can grow to such heights that it actually...more

Thunder and Lightning

Lightning is the most spectacular element of a thunderstorm. In fact it is how thunderstorms got their name. Wait a minute, what does thunder have to do with lightning? Well, lightning causes thunder....more

Types of Thunderstorms

There are two main types of thunderstorms: ordinary and severe. Ordinary thunderstorms are the common summer storm. They are usually multicell. Multicell storms consist of a line of thunderstorms in different...more

Supercell Thunderstorms and Squall Lines

A supercell thunderstorm is a huge rotating thunderstorm. It can last for several hours as a single entity. These storms are the most likely to produce long-lasting tornadoes and baseball-sized hail. Tornadoes...more

Types of Lightning

Lightning can take place in several different areas of a thunderstorm. Most lightning (about 80%) occurs within a single cloud and is called cloud-to-cloud lightning. Most of the other 20% of lightning...more

Altocumulus

Altocumulus clouds (weather symbol - Ac), are made primarily of liquid water and have a thickness of 1 km. They are part of the Middle Cloud group (2000-7000m up). They are grayish-white with one part...more

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