Updraft: September 23, 2009 Archive

Is the sun finally waking up?

Posted at 8:46 AM on September 23, 2009 by Paul Huttner (1 Comments)

Sunspots 1026 and 1027 appeared on the sun's earth side surface today. This is the first time in more than a year that two large sunspots have appeared on the same day. (Image courtesy NASA SOHO.)

It looks like the long deep solar minimum may be over.

Sunspots 1026 and 1027 have solar astronomers buzzing this week. These two sunspots mark the highest level of sunspot activity in more than a year.

So called Solar Cycle 24 is expected to kick into high gear within the next few months. These dual sunspots could mark the beginning of that increase.

Sunspots and solar activity tend to run in 11 year cycles. The current solar minimum is one of the deepest in nearly a century. The sun was "spotless" on 266 of 366 days in 2008. That's 73% of the time. You have to go back to 1913 to find a year with fewer sunspots. So far in 2009, the sun has been spotless 212 days, or about 80% of the time.

Just how much of a role natural solar variability plays in our short term weather and our climate is an area of ongoing investigation. Most climate scientists believe that greenhouse gasses play a much larger role in forcing climate changes.

Climate forcing graph courtesy of Dr. Kerry Emanuel, MIT

It is interesting to note that though 2008 was the deepest solar minimum in nearly a century, it was the 8th warmest year on record globally. It would seem logical that if solar cycles were the primary driver of weather and climate, 2008 would have been a cooler than average year. Even with a deep solar minimum continuing this year, NOAA reports that the world's oceans were the warmest on record for summer 2009.

Space weather forecasters are predicting a rapid increase in sunspot numbers in the next few months.

It will be interesting to watch the sun the next few weeks to see if sunspot activity continues to increase. And it will be interesting to see where global temperatures rank in 2010.

PH

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Nice Virga photo

Posted at 4:00 PM on September 23, 2009 by Paul Huttner

Virga streaks fall from cumulus clouds Sunday. (Photo by Ken Paulman)

Here's something you don't see everyday.

Check out this photo by MPR web editor guru Ken Paulman. He took this from his back deck Sunday around 5pm in West St. Paul looking northeast.

The wispy streaks falling from the cumulus clouds are called Virga. Virga is rainfall that leaves the cloud base but evaporates before it reaches the ground. The clouds were deep enough to produce a few rain shafts, but too shallow to get much of that rain to the surface. There is also a layer of drier air underneath the cloud base that is causing the rain droplets to evaporate.

Virga is quite common in the desert southwest. Pilots know to steer clear of areas like this. Evaporational cooling in the air column underneath these areas can cause severe downdrafts. Dry microbursts can occur near these types of cloud formations.

It's good to know that what's a potential danger to pilots can be so picturesque on the ground.

PH