Category Archives: Climate

What causes urban flooding?

Urban flooding occurs when water flows into an urban region faster than it can be absorbed into the soil or moved to and stored in a lake or reservoir. It can be caused by flash flooding, coastal flooding, river floods or rapid snow melt.

On Tuesday, the Madison area experienced urban flooding caused by an intense rainfall. On that day, a daily record rainfall of 1.46 inches fell at Dane County Regional Airport, breaking the city’s previous May 27 record of 1.27 inches. The city sewage system and draining canals did not have the necessary capacity to drain away the large amounts of rain that fell in a short period of time. Continue reading

Category: Climate, Meteorology, Phenomena

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Do wind farms modify climate?

The turbines on wind farms convert the kinetic energy of the wind into electricity. So, we might expect to see some changes in the region due to this energy conversion. The impact will be a function of how big the wind farm is and how long the turbines operate.

One way to estimate changes is through observations. The best method is to compare the observation of a region before and after wind farms are installed. Unfortunately, there are rarely enough observations before the wind farm installation to make strong conclusions about any observed relationships. Continue reading

Category: Climate, Meteorology

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When is the last frost?

The growing season is often defined as the number of days between the last time the temperature was 32 degrees in spring and the first time the temperature falls to 32 in fall.

The latest frost in spring is important to gardeners as they seek to plant after a long winter, and for most plants it is wise to do so when the temperatures are likely to remain warmer than 32 degrees.
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Category: Climate, Seasons

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How does carbon dioxide affect global warming?

Since 1958, a continuous measurement of the carbon dioxide content of the atmosphere has been made at Mauna Loa Observatory in Hawaii. These observations were initiated by Charles Keeling, who died in 2005, and have been maintained by his son Ralph ever since.

Sunshine is a manifestation of solar radiation and when it is absorbed by the surface of the Earth, the surface heats up and emits a different kind of radiation, known as infrared radiation. Carbon dioxide is a special chemical in that it is transparent to solar radiation and yet it absorbs infrared radiation. Thus, the presence of carbon dioxode in our atmosphere allows sunshine to penetrate to the surface but inhibits the emission of infrared radiation to space.
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Category: Climate, Meteorology

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How long were Madison lakes frozen this year?

Lakes Mendota, Monona and Wingra opened during the second week of April.

Lake Mendota officially froze Dec. 16 and opened April 12, for an ice season of 117 days, which is 12 days longer than the median duration. Continue reading

Category: Climate, Seasons

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