Summer Storms and Rainbows

Summer thunderstorms are always the highlight of this time of year. We have had a lot of moisture this last week. Even though the season is turning into fall the sun is still strong enough to kick-start some afternoon thunderstorms. Yesterday's storm was exciting. I was sitting inside when all of a sudden the winds picked up around 7:00 PM (19:00). This was a gust front associated with a thunderstorm that had just passed through Payson. (Maybe someday I'll write about gust fronts). The winds settled down a little bit and we had a brief downpour of rain--about a quarter of an inch. There was some lightning and thunder, too. While this was a fun to watch, it got rather chilly very quick. You can see in the charts below that the temperature following the gust front decreased quickly--about 20 degrees in 20 minutes.

Here is a link to my weather station during this time: Link. (For current conditions click "current conditions" on the right side panel.)

Today's storm was a little calmer. There was even a beautiful rainbow in the backyard. Looking a little closer, I saw two rainbows!

(c) BKB

(b) BKB

The brightest rainbow is the "primary bow." Rainbows are caused by light being refracted and reflected in raindrops. Sunlight looks white, but it actually consists of all the wavelengths of light. When that light travels through a water droplet, the different wavelengths of light are separated. When thousands of water droplets refract the light, we see a rainbow. The inside of the primary bow is always violet. As you move outward the colors go as followed: indigo, blue, green, yellow, orange, and red on the outside.

(c) BKB

The second bow is called, (you guessed it) the "secondary bow." The colors in the secondary bow are reversed, with red on the inside and violet on the outside. This is because this bow is caused by a double reflection inside the drop. You may have notice that the colors are more faint. This is because not all the light is reflected off the water droplet. For each reflection, some light passes through and never reaches your eye. The double reflection for the secondary bow thus looses more light than a single reflection.

Rest In Peace GOES-12

The GOES-12 weather satellite was decommissioned August 16th after 10 years of service (Article).  GOES stands for Geostationary Operational Environmental Satellite. Geostationary satellites stay in a fixed position above the earth as is depicted in the video below. The video shows a time lapse of 10 years of weather. 

From youtube.com

"Here on Gunnison Island!"

The University of Utah maintains about ten different weather stations in northern Utah. I had the opportunity to visit the most remote stations: Gunnison Island. Gunnison Island is located in the north arm of the Great Salt Lake. That lake has to be the most unique lake in the world. The north side is at least ten times saltier than the ocean. It is salt saturated, meaning you can't dissolve any more salt in the water. Even more interesting is that the north side of the lake is red. When the boat rudders are on, it looks like it is stirring a big batch of pink lemonade. It looked like a sweet summer drink.

About once a year meteorologist go to the island to change the battery and check the instruments to make sure everything is working properly. We have had trouble with getting consistent weather data from this station for a while. To get to Gunnision Island we hitched a ride from Utah's Department of Natural Resources. They were taking water samples at different places in the lake and they were kind enough to maroon me and another from the University on the small island. The boat is made of aluminum. Salt would corrode any other material. It doesn't show up as well in the picture, but the north side of the Great Salt Lake is very red. It looked like we were boating in a giant lake of pink lemonade.

The railroad divides the north and south side of the lake. Someone was ambitious enough to move the dirt for it. Because of the divide, the north and south arms are very different. The north side is about 10 times saltier than the ocean. It is salt saturated, meaning you can't dissolve any more salt into it. There is a lot of salt extraction that they use for roads in the winter, table salt, and minerals for fertilizers. The south side of the lake is less salty (about 6 times saltier than the ocean) because there are several fresh water rivers that flow into it. There is a lot of brine shrimp that can survive in it. Unlike the north side, the water in the south side isn't red and the shrimp can't survive.

And we were marooned on the island. Our only supplies were a water bottle, a sandwich, sunscreen, and weather instruments.
Instead of carrying all the tools to the top, we only took what we thought we needed. I ended up walking back down and up to the top three times during the trip.
A view from the top of Gunnison Island. You can see the boat trail in the water. I have a lot of bragging rights right now: I'm one of only a few people to even step foot on this island.

The weather station has had troubles sending weather data to the school, but we couldn't find any immediate problem with any of the instruments. We did change the battery and cleaned the equipment.
While people in Salt Lake were experiencing the 100 degree temperatures, we enjoyed 84 degrees. It was still hot and there wasn't any shade on the island.
Here is a link to weather data from this station:http://mesowest.utah.edu/cgi-bin/droman/meso_base.cgi?stn=GNI 

Instead of a sandy beach, this is a salty beach. All the rocks and dead birds have a thick deposit of salt.






Usual brine shrimp don't live in the north side of the lake. It is too salty. There must have been a big breach from the north side because there was a lot of these little animals. Most of them were dead.





The water was very calm on the way back. It would have been perfect for water skiing, but I wouldn't want to do that here. The salt water is super dense, so crashing on the water would feel like falling on cement! 



On the way home we saw a lot of smoke from the Patch Springs fire. Above the smoke you can see the large pyrocumulus cloud. These only form above wildfires. In order to make a cloud you need two things: water vapor and rising air. Wild fires provide both of these. The hot flames heat the air, and we all know that hot air rises. And water vapor is a product of combustion and also evaporates out of the plants being burned. These clouds are often super white. This is because they are more reflective than typical clouds. Smoke is made up of a lot of tiny particles that water vapor will condense on to form cloud droplets. Since there are so many cloud droplets compared to a typical cloud they reflect more sunlight, thus appearing more white.

Earth Phase

I recently found an interesting website that lets you look at the earth or moon in it's different phases. The below figure shows the phase of the earth in real time.

http://www.fourmilab.ch/earthview/custom.html

NASA Student Airborne Research Program Final Presentation

I've mentioned in previous posts that I participated in NASA's Student Airborne Research Program this summer. Below is my final presentation. More information about SARP can be found here. Enjoy!

Meteorological effects on surface ozone in the Los Angeles Basin