Tuesday, September 29, 2015

Great Salt Lake Time Lapse 1984-2012

This image from Google's Earth Engine shows the size of the Great Salt Lake between 1984 and 2012. I image in the strength of the lake breeze is affected by the size of the lake, especially in recent years when Farmington Bay is almost completely dry.

If you zoom into Utah Lake you'll see it hasn't changed much.
Try looking at other areas, like your neighborhood, and see how it's changed!

Monday, September 28, 2015

Lunar Eclipse

Supermoon lunar eclipse on September 27, 2015. Photo taken from the University of Utah.
Did you see the lunar eclipse last night? A lunar eclipse occurs when the earth is positioned between the sun and the moon so that earth's shadow completely blocks the moon.

The moon has a reddish tint to it. This red color is caused by light scattered by earth's atmosphere, essentially the same phenomenon that causes red sunsets.

Left image illustrates light being scattered and refracted by earth's atmosphere. Blue light is scattered most efficiently (that is why the sky is blue). With enough scattering (by a long path through the atmosphere) only red light makes reaches the moon shown on the right.
Read more about the red moon at EarthSky

Friday, September 25, 2015

Adventure on Fremont "Island"

The newest addition to the University of Utah's Mesonet is a weather station on Fremont Island. Fremont Island is located in the Great Salt Lake between Antelope Island and Promontory Point. It is named after John C. Fremont who was a military officer and explorer of the western United States. He visited Fremont Island and surveyed the Wasatch Mountain Range a few years before the Mormon pioneers reached the Salt Lake Valley.

We drove out to the island yesterday morning to set up the weather station. Yes, you read that right, we drove to the island. The cartoon map image above is a little deceiving. The Great Salt Lake Level is actually really low and there is now a land bridge that makes driving to the island possible. Note: The island is privately owned. We had permission from the owner to set up the weather station and he escorted us to the island. You can see from satellite images the land bridge that exists between the Antelope Island causeway and Fremont Island. When the lake level is high it is best to take a boat.

The image on the left shows when the lake is high. The right image was taken on 10 September 2015, just over a week prior to our excursion. The drive on the lake bed is really flat and sandy, as you can see below. That hill in the distance if Fremont Island.
Castle Rock is the highest point of the Island. We didn't hike there, but there is a famous cross carved in the rocks by Kit Carson who explored the west with John Fremont.

Kit Carson's cross (photo from the internet)
The images above makes it look like the island is barren, but the island really has diverse a diverse blend of vegetation and geological formations. Our wet summer has kept the plants green. The sagebrush especially gives lots of color to the island.

The island owner pointed out some cool rocks. They are little cubes of iron. I'm no geologist, so I can't say anything more about them.

After some wild four-wheeling on the island, we reached Miller's Point or Miller's Hill which turned out to be a perfect place for a weather station.
Our escort had an ATV.
Climbing Miller's Hill
Millers Point Survey Marker
Installing weather station on Miller's Hill.

Had to get my "Station Selfie" before we left. No idea when or if I'll ever be back here.

Weather data from this station (and thousands of other stations) can be accessed via MesoWest

Here is the past 24 hour temperature:

Past 24 hour winds:

More information about the island at Deseret News and this blog.

Monday, September 21, 2015

Mountain Waves and Rotors

Mountain Waves and Rotors: September 21, 2015

A presentation given in my Mountain Meteorology class on mountain waves and rotors in the atmosphere. Click "full screen" to view notes and additional details on each slide.

Saturday, September 19, 2015

Why does an upside down jar in boiling water fill with water.

Today we harvested the grapes and made grape juice. Yum!

Before putting the grape juice in jars we sterilize them in boiling water. We put the jars in the water upside down. Over time the jars fill with water. Why???

Friday, September 18, 2015

Turbulent Flight--Caused by Gravity Waves?

I'm preparing a presentation on mountain waves and why they are concerning for pilots. Thinking back on my most turbulent flight I wonder if there were any mountain waves involved. That is a possibility.

Our approach was from the south and we flew over Utah Lake. The plane began to say, bump, and drop suddenly. There was one time that the stewardesses all fell to the floor and grabbed onto the seat around them.

This is the MODIS image for the day I flew into Salt Lake City on June 14, 2014. There is evidence of wave like structure in the clouds on that day...

The sounding appears to have the ingredients of a mountain wave--stable air at mountain peak and cross mountain winds with winds from the west.

Here is a view from the plane and from near the airport after landing. Kind of hard to determine if there were mountain waves.

Thursday, September 17, 2015

Monday, September 14, 2015

I'm leaving work late.

It's raining, and I really don't want to wait at the bus stop in the rain. Hopefully it will pass in an hour. I'm sure I'll hear from my Provo about the crazy rain they are getting right now.

Friday, September 11, 2015

El Nino: What does it mean for Utah?

You may have heard that this year is an El Nino year. What does that mean? El Nino referrers to warmer than normal ocean temperatures near the equator in the eastern Pacific Ocean.

The anomalous ocean temperatures influences the global weather is some very profound ways. In fact, I've heard from a climate professor that the impacts of El Nino on global climate are only trumped by the annual seasonality caused by earth's tilt rotation around the sun. More info here.

So, what how will weather be different this winter? That is hard to say. On average, the northwest United States tends to have dry and warm conditions during El Nino years and the Southwest tends to be me wet. Utah is stuck in the middle of these two trends. It we could have an average year. We could have a more wet year. Or, we could have a more dry year. But whatever crazy happens this winter I'm sure everyone will make sure to put the blame on El Nino.

Wednesday, September 9, 2015

Deer Creek Fire: Smoke and Ozone

A fire up Provo Canyon near Deer Creek Reservoir has burned over 600 acres and, as of this morning, is only 5% contained. Fires up canyons are dangerous to firefighters because canyon winds can change direction and spread the fire rapidly. Read the KSL story here.

Yesterday I drove up the canyon to measure ozone concentrations. Ozone at the bottom of the canyon was low, in the 40s ppb. Near the fire the ozone concentration was elevated with a max concentration of 64 ppb. Wildfires is one source of ground level ozone (review article here).

Smoke plume seen from MODIS Terra satellite
Smoke plume seen from MODIS Aqua satellite later that day.

Saturday, September 5, 2015

Anemometers measure wind

Yesterday I walked past the large fountain at Temple Square yesterday and saw an anemometer spinning on a post. "That's funny," I thought. "Why is the church interested in winds?" I sat on a bench and worked on some homework for an hour. Then the reason for the anemometer dawned on me! The fountain hadn't turned on because it was windy. When the wind is high they keep the fountain off so the water doesn't blow on people.

On a day that isn't windy the fountain looks like this...

This isn't the first one I've seen an anemometer on the church's property. I've seen anemometers at several temples, including the Provo temple. My brother confirmed my theory. He had read an article earlier about the new anemometer installed at the new Provo City Center temple for the new fountain.
Anemometer at the Provo Utah temple
Anemometer at the Provo City Center Temple

Here's the new fountain being installed...

Friday, September 4, 2015

Kelvin Hemholtz Wave

Last year one of the scouts in my weather merit badge class sent me this picture of a Kelvin-Helmholtz wave cloud. The photo was taken in Springville, Utah.

Thursday, September 3, 2015

Blowing Dust seen from Farnsworth Peak

This morning I went up to Farnsworth peak to retrieve an ozone monitor that has taken measurements all summer. Strong southerly winds kicked up dust from the dry lake bed of the Great Salt Lake.

Since the view was so nice, here are a bunch more pictures...