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Is the Sun Playing a Role in the Earth’s Global Warming?
The sun helps maintain Earth’s climate to be warm enough for us to survive. Even subtle changes in Earth’s orbit around the sun have led to and ended past ice ages. This relationship between Earth’s climate and its orbit around the Sun is well known.
The sun’s activity and appearance goes though cycles, with one solar cycle taking 11 years to complete. The current cycle began at the end of 2019 and will reach peak levels of activity in 2025. During a solar cycle, the amount of solar radiation reaching Earth varies. These changes have a variety of effects on Earth’s atmosphere, including auroras. Continue reading
How can the Upper Midwest get such high dew points every year?
The dew point temperature is a measure of the amount of water vapor in the atmosphere and is also a good way to tell how uncomfortable you might feel on a hot day. Hot days and high water vapor contents are a serious health risk for some. Also, high water vapor content is a key fuel for severe thunderstorms.
There are three primary sources of water vapor that address this question: advection of water vapor largely from the Gulf of Mexico, evaporation over the Great Lakes, and transpiration from corn fields. The contribution from the Great Lakes in summer is minimal in comparison to the other factors, except maybe near the shorelines. Continue reading
Does the U.S. have a new weather satellite?
Weather satellites fly around Earth in two basic orbits: a geostationary Earth orbit (abbreviated as GEO) and a low Earth orbit (abbreviated as LEO). LEO satellites’ orbits often travel over the Earth’s polar regions, flying at an altitude of 530 miles. Geostationary satellites orbit Earth as fast as Earth spins and so hover over a single point above Earth at an altitude of about 22,300 miles. To maintain its position, a GEO satellite must be located over the equator. In contrast, polar satellites go around from pole to pole as the Earth rotates beneath the satellite; each orbit is slightly to the west of the previous one.
Satellite observations provide valuable information to meteorologists. The United States usually operates two geostationary satellites called GOES (Geostationary Operational Environment Satellite). One has a good view of the East Coast; the other is focused on the West Coast. They are a basic element of the U.S. weather monitoring and forecasting enterprise. The first GOES satellite, GOES-1, was launched in October 1975. Upgrades to the instruments are made as needed and the U.S. is currently in the fifth generation of GOES satellites. These are the GOES-R series, first launched in 2016. Continue reading
Is our rainy summer finally drying out a bit?
Readers may recall we reported on the unusually wet nature of our late spring/ early summer about a month ago. At that time, Madison had recorded the wettest May 1-July 15 period since at least 1939 while averaging more than 2.5 degrees Fahrenheit above normal for that same period.
Another month has ticked away in this summer, and it has been a bit different than the ones that came before it. Through Aug. 15, Madison has recorded 1.73 inches of precipitation, which is 0.35 below normal. Ten of the first 15 days of the month had no precipitation at all and, from Aug. 7 to Aug. 13 we had a streak of seven straight days with no rain at all. That is now the longest dry streak since May 1. Continue reading
What is Tornado Alley?
A tornado is a powerful column of winds that rotate around a center of low pressure. The winds inside a tornado spiral inward and upward, often exceeding speeds of 300 mph. Tornadoes form in atmospheres that have extremely unstable moist air, large amounts of vertical wind shear and weather systems, such as fronts or thunderstorms, that force air upward.
The continental United States provides these three ingredients in abundance. Continue reading
