Category Archives: Phenomena

Science-based policy is shrinking ozone hole

The Southern Hemispheric ozone hole usually begins to develop in mid- to late August, as the hemisphere emerges from its winter, and peaks in mid-October.

This year it first appeared closer to the end of August and by mid-September was 18.48 million square kilometers in size, smaller than in recent years, including both 2022 and 2023. Though this year’s slow start does not necessarily reflect a recovery of the ozone layer, it does support the notion that expert guidance has made a positive contribution to this vexing problem. Continue reading

Category: History, Phenomena

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Do weather radars detect more than precipitation?

Yes. Radar, an acronym for RAdio Detection And Ranging, consists of a transmitter and a receiver. The transmitter emits radio wave pulses outward in a circular pattern. Objects scatter these radio waves, sending some energy back to the transmitting point where it is detected by the radar’s receiver. The intensity of this received signal indicates the size and density of the suspended objects, such as precipitation. The time it takes for the radio wave to leave the radar and return indicates the distance.

Radar is designed to detect precipitation intensity and type, but it can detect living things as well. Flying insects in huge numbers can reflect enough energy back to a radar site to be detected. As an example, mayflies emerge in summer in enormous numbers around the Mississippi River between Wisconsin and Minnesota and are often detected by the weather radar in La Crosse, WI. Continue reading

Category: Phenomena, Seasons

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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

Category: Climate, Phenomena, Seasons

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Do tornadoes occur over all parts of Earth?

The only continent that has not recorded a tornado is Antarctica. Otherwise, tornadoes can happen in just about any location.

North America, and specifically the United States, accounts for more than 75% of the world’s reported tornadoes. Other tornado-prone areas around the globe include western Canada, Argentina, the western Mediterranean, Japan, Bangladesh, Australia, New Zealand and South Africa. Continue reading

Category: Meteorology, Phenomena, Severe Weather

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Are ‘chem trails’ a real thing?

For years we have fielded questions on our monthly radio show on WHA regarding the nature of condensation trails left in the wake of jet airliners. These contrails are composed of ice crystals that develop from the exhaust of jet … Continue reading

Category: Phenomena

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