Where does wind come from? September 24, 2007

Without the wind, there would be little change in the weather. And, when used appropriately, it can aid in the production of energy.

After spending time at the beach on Labor Day, Tatiana Williams asked her parents: “Where does wind come from?”

The simple answer: Differences in air pressure — but it’s more complex than that.

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As the atmosphere tries to achieve tranquility, the air gets mixed up. You see it on Channel 3’s Early Warning Weather maps all the time with high and low pressures. An area of high pressure represents sinking air and a clockwise flow. A low pressure is rising air and the flow is counterclockwise.

Between the two, a force is created: The greater the difference in pressure, the stronger the wind. Also, the closer they are together, the greater the intensity. So, if you’re standing with your back to the wind, low pressure will be on your left and high pressure on your right.

But what causes the difference in air pressure? That has to do with the sun and the unequal heating of the Earth, which is a sphere and is approximately 70 percent water, leading to differences in temperature and therefore density with the expansion and contraction of air. The rotation of the earth also plays a role as air masses shift around the globe.

How Leaves Change Color September 16, 2007

New England is well-known for a vibrant show of color during the fall season. Leaf peepers are anxiously await the transition while most of Connecticut remains green in September with only a few splashes of color here and there.

Mark’s Video: How Leaves Change Color

Speaking of color, it is always present in the leaf. As autumn sets in, chlorophyll begins to break down and the green color fades away. This happens as water is cut off from entering the leaf, allowing all of the other colors to come out — from yellow to orange to red.

Typically, shorter days and cool nights will signal trees that autumn has arrived leading to this change in leaf color before those leaves fall from the trees.

If you’re planning travel to catch the sights of the season, be sure to catch our foliage reports with a map showing Northeast’s foliage progress every week. So far, there is little or no change.

“With a rainfall deficit of over 2.5 inches for the year, the third driest August and a recent dry spell of 17 consecutive days without rain, the Home and Garden Education Center at the Connecticut Cooperative Extension System is expecting a lackluster show of color this year since many trees are stressed. For instance, given the conditions, maples will turn color earlier and then faster to brown; therefore limiting the time span of viewing.

Fall Equinox Signals Change September 10, 2007

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For you summer lovers out there, the warm weather has held out for the past few weeks. But we’re nearing a big transition period when the effect of the sun will begin changing. Coming up in just 15 days from now, we enter the autumn season.

This year, the equinox falls on Sunday, Sept. 23, at 5:51 a.m. On that day, the sun is above the equator — night and day are of approximately equal length.

This is the opposite of what happens at a solstice. As we head through fall and toward winter, the northern hemisphere tilts away from the sun and we lose daylight.

The southern hemisphere gains daylight heading toward summer and this process is under way. In fact, each day, we lose two to three minutes of light as the sun rises later and sets earlier.

So, even though we’re enjoying some warmer weather as of late, it’s starting to feel like a change is under way with the transition from one season to the next.