Evening clouds

As usual, we saw some nice cloud formations as we left the grocery store Friday night. This was from the parking lot.

crepuscular_wmlotThe crepuscular rays weren’t particularly noticeable as I looked at the clouds, but they showed up well in the photo. I like the way the cloud in the middle left is half illuminated and half in shadow.

When we drove home, there were more nice clouds. We managed to snap a few shots and got this one.

crepuscular_huffaker2Again, the crepuscular rays were not really noticeable as we drove, but they showed up in the photos. They aren’t extremely strong, but they’re definitely there.

Another interesting (at least to me) feature of the clouds Friday afternoon and evening was the way they changed. Late in the afternoon, but well before sunset, there were growing cumulus clouds everywhere. They had flat bottoms and billowing tops.

flat-bottom cloud

The bottoms of the clouds are all at about the same altitude, which is where the air from lower altitudes reaches saturation as it rises because of solar heating. At that point, water vapor starts to condense and form clouds. Condensation adds heat to the air, and it continues to rise. As it rises, more water vapor condenses and more latent heat is released. Under different conditions, these clouds could have eventually developed into thunderstorms. But, alas, none did, at least around us.

As the evening progressed and the solar heating decreased, the energy that drove these clouds’ development dissipated and the clouds began to change. There just wasn’t enough energy available to drive any more development once the sun went down. The flat bottoms became ragged and the tops stopped billowing. Some became closer to stratus clouds and others remained more like cumulus clouds. Eventually they turned into what we saw on our way home.

This is a panorama from our new house site made just as we reached home.

clouds_panoSome of these clouds still have billowy tops, but there was not much going on by this time.

 

Two thunderstorms, one night

Tuesday evening Leah and I noticed some dramatic clouds in the sky in two different places. I saw a yellow glow from the rear of the house and went outside on the deck to look. Off to the left, which is roughly east, I saw a cloud that was illuminated by the setting sun. It showed some fair vertical development.

clouds1

At the same time Leah was in the front. She called me out there and pointed to a cloud formation directly behind the house that I couldn’t see from the deck because of the trees. This was pretty much due south of us. It also showed some vertical development to the right in this image.

clouds2

Here is a panorama I shot with our little Nikon S9700, which has a built-in panorama function.

2thunderstorms

It looked like there was some rain beneath the cloud to the east, but it was late enough that it was hard to tell. A little later, after the sun had set completely, I went out onto the deck and saw this.

This was not a severe thunderstorm, so the lightning strokes were infrequent. I edited the video to get several strokes into a short period.

This was what my phone’s weather radar app showed at the same time. The red pushpin is our location.

radarimage

You can see that both cloud formations were producing rain, although not heavy rain.

You can see in the first two images that there was no anvil formation on either cloud, so they were not exceptionally high. I tried to do some rough calculations of the height of the cloud to the east, which was just south of downtown Rome. I had to estimate its distance and the elevation angle to the top of the cloud. I figure that the cloud top was somewhere between 14,000 and 19,000 feet. That sounds reasonable for the early development stages of a not-particularly severe thunderstorm.

A glory at Kwaj

In about 1987 I had a chance to travel to Kwajalein Atoll in the Pacific Ocean. Kwajalein Atoll is part of the Republic of the Marshall Islands. It’s about 10 degrees north of the equator and about 13 degrees on the other side of the International Dateline (the US government stretches the dateline west to include Kwajalein in the same date as the mainland US). It’s 2500 air miles from Hawaii, which is about 2400 air miles from Los Angeles, which is just under 2000 air miles from Atlanta. It is, in other words, remote.

The US has operated a base on Kwajalein Island since the end of World War II US Army Kwajalein Atoll, or USAKA). They also operate bases on other islands in the chain, including one called Roi-Namur.

I took this picture when I flew from Kwajalein to Roi-Namur (Roi and Namur were originally two separate islands, but they were joined by an artificial causeway by the Japanese during World War II.)

theatoll

Here is another I took on the same flight.

glory2

This is a glory. This is not an especially good example, but any example of a glory is a wonder. A glory is a bright ring that forms around the shadow of an observer when the sun is behind the observer and the observer looks towards his own shadow. Glories can often be seen from airliners flying over clouds, or in fog with bright lights behind the observer. I showed a glory in fog in a previous post, although I didn’t actually identify it as a glory. You might also see a glory in smoke.

The Wikipedia article on glories indicates that there is some scientific uncertainty about the source of the phenomenon, but other sources indicate a fairly simple explanation that I think is accurate. It is basically caused by scattering of light by cloud drops or other particles in the air. In the case of most particles or droplets, most of the light that interacts with them is scattered in the same general direction as it was originally traveling. That’s why, when clouds cover the sun or moon, you can see a bright area around where the sun or moon is, as long as the clouds aren’t thick enough to completely block the light. However, a large portion of the incident light is scattered back towards the source. That’s what causes the bright ring around the observer’s shadow. Back scattering, as it’s known, is what makes it hard to see in thick fog if you use your car’s high beams.

The (relatively) simple explanation is also consistent with the fact that you can see a similar phenomenon on a sunny day if you look at your shadow on the ground. There should be a brighter area on the ground surrounding your shadow. That bright area is light that is preferentially scatted back towards the light source.

The Wikipedia article about Kwajalein Atoll has at least one mistake. It says that the total area of the atoll islands is about 16 square miles, when it is, in fact, about six square miles. They may have been referring to the total area of the Marshal Islands, which includes other atolls.

The Marshall Islands are probably most famous as the site of a lot of the US atmospheric nuclear weapon testing.

Kwajalein Atoll is now used by the US Army as a missile and missile defense test site. The current name of the site is the Ronald Reagan Ballistic Missile Defense Test Site (usually called simply the Reagan Test Site, or RTS), named in honor of President Ronald Reagan because of his pursuit of the fantasy of a defense against a large-scale missile attack on the United States.

More than 70 years ago, in 1944, US forces invaded Kwajalein and Roi-Namur as part of the strategy of island-hopping across Pacific on the way to the Japanese homeland. Kwajalein was invaded a few months after Tarawa, which was the first really bloody lesson the US learned about what fighting the Japanese would be like. The planners for the Tarawa invasion thought they had bombed and shelled the island so much that there would be little resistance; that turned out not to be the case. So when they planned the amphibious invasion of Kwajalein, by one estimate, they poured about 6000 tons of bombs and shells onto the island. That’s equivalent to about 40 percent of the size of the atomic bomb dropped on Hiroshima. Another estimate was that it amounted to about 100 pounds of explosives per square foot of the island.

The battle for Kwajalein Island lasted four days. It’s pretty amazing to think about, especially if you have actually visited that island. At almost any point it’s possible to see the ocean on both sides at the same time. Back then I was still running; it was an easy run around the entire perimeter of the island.

The invasion of Roi-Namur occurred next. That island is tiny, even in comparison to Kwajalein Island. That battle took a day. As a result of that 24 hours of fighting, four Medals of Honor were awarded.

There are quite a few relics from the Japanese occupation and the US invasion. Here is a Japanese headquarters building.

japanesebuilding

This is what’s left of one of the Japanese defense positions.
gunmount

This is a wall of a building with graffiti left from that time.

graffitiwall

This is some of the debris left from US equipment lost on the beach. I found some old rifle cartridges in the water near Roi, but have long since lost them.

invasiondebris

Today, the islands are pretty.

islandpalms

windypalms

Base personnel cut the coconuts down from the trees to keep them from falling onto the heads of residents.

It’s not what you think of as a tropical paradise, but that image probably comes from volcanic island rather than coral atolls. Coral atolls have no mountains. The highest natural elevation on Kwajalein is probably less than six feet above mean sea level. Fortunately for Kwajalein, it is close enough to the equator that hurricanes almost never hit the island. However, when I was there, a strong storm had only recently hit the islands, resulting in a lot of losses for the Marshallese. Kwajalein’s and Roi’s facilities weren’t harmed, but those facilities are American and more sturdily built.

Kwajalein Island and Roi-Namur Island are reserved for US personnel. Any Marshallese working on the islands must return back to their home islands after each work day.

The reason US personnel are at USAKA is to take part in US missile testing. US intercontinental missiles are sometimes launched from the coast of California to reenter at Kwajalein as part of routine testing of US offensive weapons. Personnel at Kwaj also take part in missile defense testing. This is used for both purposes.

altair

This is ALTAIR (ARPA Long-Range Tracking and Instrumentation Radar), operated by MIT Lincoln Laboratory. ARPA is the Advanced Research Projects Agency, which is currently called the Defense Advanced Research Projects Agency, or DARPA. There are other radars located around the islands.

My visit was part of a small sounding rocket test associated with the old Ballistic Missile Defense program, the one that was going to protect the US from a massive Soviet missile attack. I flew into Kwaj one day and then flew with a few of my fellow contractors and some government workers to the island of Roi-Namur. I stayed at Roi for a few days before the missile test I was involved with. It was a nice vacation. I spent it walking around the island, reef walking and taking photographs (the slides from which the images here are scanned). The weather was warm and humid but reasonably pleasant. The facilities on the island are pretty primitive in some respects. It was at Roi that I learned that if you don’t keep Diet Coke cool, the Aspartame in it breaks down into something that doesn’t taste very good. At all.

Our test, which was a small one, failed. It involved what’s called a sounding rocket, which is a smallish missile that barely reaches outer space and then returns. Our missile had three stages. When the first stage separated, it “chuffed” (residual propellant ignited and puffed out). When it chuffed, the first stage bumped into the second stage and damaged it. The missile then went out of control and had to be destroyed.

So we packed up and went back home, and I never went back again.

Top o’ the mornin’

I took this picture Monday morning when I walked the dogs up to the top of the mountain. It was about 9:30, long after sunrise. Just right of center, where the steam plumes are, you can see the remains of the temperature inversion from the calm, clear atmosphere we had over Sunday night.

topothemornin

The foggy, linear stream on the left side of the plumes is the top of the inversion. If we had walked right after sunrise, the top of the inversion would probably have been more obvious, but it was already dissipating by this time. It would, however, have been at approximately the same level in the atmosphere.

An inversion serves as a cap on the atmosphere close to the surface. It traps moisture or pollutants that are beneath the top of the inversion. The temperature normally decreases as you go up higher in the troposphere. Air that is warmer than the air at the surface (like smoke from a brush fire) will tend to rise through the troposphere because it is lighter than its surroundings. In an inversion, the air actually gets warmer is you go up, so things like smoke will rise for a while, but will tend to stop at a low altitude. A very hot plume can push through the inversion and then continue to rise. The steam plumes are doing that.*

The steam plumes are coming from a paper mill. The two tall stacks to the right of the steam plumes are an old and a new stack at Plant Hammond, one of the two Georgia Power coal-fired power generating plants we can see from Lavender Mountain.

Plant Hammond’s active stack is 675 feet (205.8 m) tall. Although nowhere near the tallest stack in the world, it is tall enough to be on the Wikipedia list of the tallest stacks in the world.

It’s tall for a reason – the Clean Air Act, which goes back more than 50 years. That act has provisions that limit the concentration of pollutants at ground level. One might think that the logical way to do that would be to limit the emission of pollutants, but it happens that if you introduce the pollutants high enough in the air, they will have been diluted enough that by the time they can reach the ground, they will meet the standards. So the Georgia Power stacks are high enough to push emissions above the top of any reasonably probable inversion height. If the stacks were below the top of the inversion, their emissions might reach the ground because they might be trapped by a particularly strong inversion, or they might just reach the ground because of other atmospheric conditions. When the emissions are injected into the atmosphere high enough, they will be diluted enough to meet the letter of the law.

Rome happens to be in a nonattainment area for atmospheric particulate matter. That status somewhat limits the industrial development of this area. Our local newspaper, the Rome News-Tribune, does not like that. They have published editorials mocking the nonattainment status (like saying that our air seems clear enough to them).

To cast doubt on the legitimacy of the measurements that caused the nonattainment status, the editorial writer has pointed out that the air quality monitoring station is located near the base of the Plant Hammond stack. The implication seems to be that only an idiot would measure air quality that close to a pollution source, and thus the measurement must not be representative of Rome’s true air quality. I have written letters to them in the past pointing out that if you want to avoid measuring the emissions from a tall stack, the best place to put your instrumentation is at the very bottom of the stack. That is perhaps not intuitively obvious, but it is nevertheless true. However, the truth seems not to be a persuasive argument when it comes to commercial development and newspaper editorialists. (I might have mentioned this in an earlier post.)

You might be wondering why the top of the inversion is so much lower than the top of the mountain, where I have mentioned on several occasions that we are warmer than the surrounding lowlands because of a temperature inversion. The reason is that although the top of Lavender Mountain is above the actual inversion, the conditions that cause the inversion also work on the atmosphere up here. As the air on the mountaintop cools, it flows downhill into the lower areas, reinforcing the inversion down there. That air is replaced up here by the surrounding air, which is warmer than the air that flows down the mountain. I have mentioned before that we can be as much as 10 degrees F warmer than the air at the bottom of the mountain.

Oh, and Happy St. Patrick’s Day.

* The tropopause acts like the top of a temperature inversion. The air temperature gets lower as you go up in altitude until it reaches the tropopause. In the stratosphere, which is the layer above the troposphere, the air gets warmer as you go up. That’s why thunderstorms form anvil tops when they get to the tropopause. The clouds hit the warmer air and their buoyancy can’t get them any higher. At that point they tend to spread out sideways, forming the anvil top. Occasionally a very strong thunderstorm can push its clouds through the tropopause, but not very much higher.

Changing weather

Wednesday we had the warmest day so far this year, but there’s a cold front on the way. The front is moving from the west, but after a short shower, the eastern sky gave a hint of change to come.

rainbow_4mar15

There was a complete rainbow, but I couldn’t get the entire bow in the frame. The other side was behind some trees, so it was hard to see anyway. There was still a little of it left when I took the dogs out later.

sky_4mar15

Despite our high up here of around 67 on Wednesday, we are under a winter weather advisory for Thursday. We are at the southern edge of the advisory area, so I doubt that we will see much frozen precipitation.